BioPAX pathway converted from "Activation of ATR in response to replication stress" in the Reactome database. Activation of ATR in response to replication stress Genotoxic stress caused by DNA damage or stalled replication forks can lead to genomic instability. To guard against such instability, genotoxically-stressed cells activate checkpoint factors that halt or slow cell cycle progression. Among the pathways affected are DNA replication by reduction of replication origin firing, and mitosis by inhibiting activation of cyclin-dependent kinases (Cdks). A key factor involved in the response to stalled replication forks is the ATM- and rad3-related (ATR) kinase, a member of the phosphoinositide-3-kinase-related kinase (PIKK) family. Rather than responding to particular lesions in DNA, ATR and its binding partner ATRIP (ATR-interacting protein) sense replication fork stalling indirectly by associating with persistent ssDNA bound by RPA. These structures would be formed, for example, by dissociation of the replicative helicase from the leading or lagging strand DNA polymerase when the polymerase encounters a DNA lesion that blocks DNA synthesis. Along with phosphorylating the downstream transducer kinase Chk1 and the tumor suppressor p53, activated ATR modifies numerous factors that regulate cell cycle progression or the repair of DNA damage. The persistent ssDNA also stimulates recruitment of the RFC-like Rad17-Rfc2-5 alternative clamp-loading complex, which subsequently loads the Rad9-Hus1-Rad1 complex onto the DNA. The latter '9-1-1' complex serves to facilitate Chk1 binding to the stalled replication fork, where Chk1 is phosphorylated by ATR and thereby activated. Upon activation, Chk1 can phosphorylate additional substrates including the Cdc25 family of phosphatases (Cdc25A, Cdc25B, and Cdc25C). These enzymes catalyze the removal of inhibitory phosphate residues from cyclin-dependent kinases (Cdks), allowing their activation. In particular, Cdc25A primarily functions at the G1/S transition to dephosphorylate Cdk2 at Thr 14 and Tyr 15, thus positively regulating the Cdk2-cyclin E complex for S-phase entry. Cdc25A also has mitotic functions. Phosphorylation of Cdc25A at Ser125 by Chk1 leads to Cdc25A ubiquitination and degradation, thus inhibiting DNA replication origin firing. In contrast, Cdc25B and Cdc25C regulate the onset of mitosis through dephosphorylation and activation of Cdk1-cyclin B complexes. In response to replication stress, Chk1 phosphorylates Cdc25B and Cdc25C leading to Cdc25B/C complex formation with 14-3-3 proteins. As these complexes are sequestered in the cytoplasm, they are unable to activate the nuclear Cdk1-cyclin B complex for mitotic entry.<p>These events are outlined in the figure. Persistent single-stranded DNA associated with RPA binds claspin (A) and ATR:ATRIP (B), leading to claspin phosphorylation (C). In parallel, the same single-stranded DNA:RPA complex binds RAD17:RFC (D), enabling the loading of RAD9:HUS1:RAD1 (9-1-1) complex onto the DNA (E). The resulting complex of proteins can then repeatedly bind (F) and phosphorylate (G) CHK1, activating multiple copies of CHK1. Authored: Borowiec, JA, 2006-02-25 17:40:15 Edited: D'Eustachio, P, 2006-02-25 17:41:28 LEFT-TO-RIGHT Stalling of DNA replication fork and RPA binding When a DNA replication fork encounters DNA lesions (e.g., cyclobutane pyrimidine dimers or alkylated bases) stalling of the replicative DNA polymerase may occur. This can lead to dissociation or 'uncoupling' of the DNA polymerase from the DNA helicase and generation of long regions of persistent ssDNA. Uncoupling can also occur in response to other genotoxic stresses such as reduced dNTP pools caused by hydroxyurea treatment which inhibits cellular ribonucleotide diphosphate reductase. The exposed ssDNA is bound by the single-stranded DNA binding protein RPA. The persistent nature of this RPA-ssDNA complex (as opposed to a more-transient complex found at an active replication fork) allows it to serve as a signal for replication stress that can be recognized by the ATR-ATRIP and Rad17-Rfc2-5 complexes.<p>RPA associates with ssDNA in distinct complexes that can be distinguished by the length of ssDNA occluded by each RPA molecule. These complexes reflect the progressive association of distinct DNA-binding domains present in the RPA heterotrimeric structure. Binding is coupled to significant conformational changes within RPA that are observable at the microscopic level. Presumably, the different conformations of free and ssDNA-bound RPA allow the protein to selectively interact with factors such as ATR-ATRIP when bound to DNA. Authored: Borowiec, JA, 2006-02-25 17:40:15 Edited: D'Eustachio, P, 2006-02-25 17:41:28 Persistent single-stranded DNA Reactome DB_ID: 176104 nucleoplasm GENE ONTOLOGY GO:0005654 Reactome Database ID Release 83 176104 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176104 Reactome R-ALL-176104 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-ALL-176104.2 Reactome http://www.reactome.org ChEBI 61120 additional information MI MI:0361 RPA heterotrimer Reactome DB_ID: 68462 RPA1 DNA Replication factor A protein A1 (70kD) RPA70 Replication protein A 70 kDa DNA-binding subunit RP-A RF-A Replication factor-A protein 1 Single-stranded DNA-binding protein Reactome DB_ID: 68461 UniProt:P27694 RPA1 RPA1 REPA1 RPA70 FUNCTION As part of the heterotrimeric replication protein A complex (RPA/RP-A), binds and stabilizes single-stranded DNA intermediates, that form during DNA replication or upon DNA stress. It prevents their reannealing and in parallel, recruits and activates different proteins and complexes involved in DNA metabolism (PubMed:27723720, PubMed:27723717). Thereby, it plays an essential role both in DNA replication and the cellular response to DNA damage (PubMed:9430682). In the cellular response to DNA damage, the RPA complex controls DNA repair and DNA damage checkpoint activation. Through recruitment of ATRIP activates the ATR kinase a master regulator of the DNA damage response (PubMed:24332808). It is required for the recruitment of the DNA double-strand break repair factors RAD51 and RAD52 to chromatin in response to DNA damage (PubMed:17765923). Also recruits to sites of DNA damage proteins like XPA and XPG that are involved in nucleotide excision repair and is required for this mechanism of DNA repair (PubMed:7697716). Also plays a role in base excision repair (BER) probably through interaction with UNG (PubMed:9765279). Also recruits SMARCAL1/HARP, which is involved in replication fork restart, to sites of DNA damage. May also play a role in telomere maintenance (PubMed:17959650). As part of the alternative replication protein A complex, aRPA, binds single-stranded DNA and probably plays a role in DNA repair. Compared to the RPA2-containing, canonical RPA complex, may not support chromosomal DNA replication and cell cycle progression through S-phase. The aRPA may not promote efficient priming by DNA polymerase alpha but could support DNA synthesis by polymerase delta in presence of PCNA and replication factor C (RFC), the dual incision/excision reaction of nucleotide excision repair and RAD51-dependent strand exchange (PubMed:19996105).SUBUNIT Component of the canonical replication protein A complex (RPA), a heterotrimer composed of RPA1, RPA2 and RPA3 (PubMed:27723720, PubMed:27723717). Also a component of the aRPA, the alternative replication protein A complex, a trimeric complex similar to the replication protein A complex/RPA but where RPA1 and RPA3 are associated with RPA4 instead of RPA2 (PubMed:7760808, PubMed:19116208). The DNA-binding activity may reside exclusively on the RPA1 subunit. Interacts with PRPF19; the PRP19-CDC5L complex is recruited to the sites of DNA repair where it ubiquitinates the replication protein A complex (RPA) (PubMed:24332808). Interacts with RIPK1 (PubMed:16135809). Interacts with the polymerase alpha subunit POLA1/p180; this interaction stabilizes the replicative complex and reduces the misincorporation rate of DNA polymerase alpha by acting as a fidelity clamp (PubMed:9214288). Interacts with RAD51 and SENP6 to regulate DNA repair (PubMed:20705237). Interacts with HELB; this interaction promotes HELB recruitment to chromatin following DNA damage (PubMed:22194613, PubMed:26774285). Interacts with PRIMPOL; leading to recruit PRIMPOL on chromatin and stimulate its DNA primase activity (PubMed:24126761, PubMed:25550423, PubMed:28534480). Interacts with XPA; the interaction is direct and associates XPA with the RPA complex (PubMed:7700386, PubMed:9699634, PubMed:10563794). Interacts with ETAA1; the interaction is direct and promotes ETAA1 recruitment at stalled replication forks (PubMed:27601467, PubMed:27723720, PubMed:27723717). Interacts with RPA1; this interaction associates HROB with the RPA complex (By similarity).PTM DNA damage-induced 'Lys-63'-linked polyubiquitination by PRPF19 mediates ATRIP recruitment to the RPA complex at sites of DNA damage and activation of ATR (PubMed:24332808). Ubiquitinated by RFWD3 at stalled replication forks in response to DNA damage: ubiquitination by RFWD3 does not lead to degradation by the proteasome and promotes removal of the RPA complex from stalled replication forks, promoting homologous recombination (PubMed:26474068).PTM Sumoylated on lysine residues Lys-449 and Lys-577, with Lys-449 being the major site. Sumoylation promotes recruitment of RAD51 to the DNA damage foci to initiate DNA repair through homologous recombination. Desumoylated by SENP6.SIMILARITY Belongs to the replication factor A protein 1 family. Homo sapiens NCBI Taxonomy 9606 UniProt P27694 2 EQUAL 616 EQUAL Reactome Database ID Release 83 68461 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68461 Reactome R-HSA-68461 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68461.2 1 RPA2 DNA Replication factor A protein 2 (32kD) RPA32 Replication protein A 32 kDa subunit RP-A RF-A Replication factor-A protein 2 Reactome DB_ID: 68457 UniProt:P15927 RPA2 RPA2 REPA2 RPA32 RPA34 FUNCTION As part of the heterotrimeric replication protein A complex (RPA/RP-A), binds and stabilizes single-stranded DNA intermediates, that form during DNA replication or upon DNA stress. It prevents their reannealing and in parallel, recruits and activates different proteins and complexes involved in DNA metabolism. Thereby, it plays an essential role both in DNA replication and the cellular response to DNA damage. In the cellular response to DNA damage, the RPA complex controls DNA repair and DNA damage checkpoint activation. Through recruitment of ATRIP activates the ATR kinase a master regulator of the DNA damage response. It is required for the recruitment of the DNA double-strand break repair factors RAD51 and RAD52 to chromatin in response to DNA damage. Also recruits to sites of DNA damage proteins like XPA and XPG that are involved in nucleotide excision repair and is required for this mechanism of DNA repair. Also plays a role in base excision repair (BER) probably through interaction with UNG. Also recruits SMARCAL1/HARP, which is involved in replication fork restart, to sites of DNA damage. May also play a role in telomere maintenance.SUBUNIT Component of the replication protein A complex (RPA/RP-A), a heterotrimeric complex composed of RPA1, RPA2 and RPA3 (PubMed:2406247, PubMed:19116208, PubMed:10449415). Interacts with PRPF19; the PRP19-CDC5L complex is recruited to the sites of DNA repair where it ubiquitinates the replication protein A complex (RPA) (PubMed:24332808). Interacts with SERTAD3 (PubMed:10982866). Interacts with TIPIN (PubMed:17141802, PubMed:17296725). Interacts with TIMELESS (PubMed:17141802). Interacts with PPP4R2; the interaction is direct, DNA damage-dependent and mediates the recruitment of the PP4 catalytic subunit PPP4C (PubMed:20154705). Interacts (hyperphosphorylated) with RAD51 (PubMed:20154705). Interacts with SMARCAL1; the interaction is direct and mediates the recruitment to the RPA complex of SMARCAL1 (PubMed:19793861, PubMed:19793862, PubMed:19793863). Interacts with RAD52 and XPA; those interactions are direct and associate RAD52 and XPA to the RPA complex (PubMed:7700386, PubMed:8702565, PubMed:17765923, PubMed:11081631). Interacts with FBH1 (PubMed:23319600). Interacts with ETAA1; the interaction is direct and promotes ETAA1 recruitment at stalled replication forks (PubMed:27601467, PubMed:27723720, PubMed:27723717). Interacts with RFWD3 (PubMed:21504906, PubMed:21558276, PubMed:26474068, PubMed:28575657). Interacts with DDI2 (PubMed:29290612).INDUCTION Translationally up-regulated in response to DNA damage (at protein level).PTM Differentially phosphorylated throughout the cell cycle, becoming phosphorylated at the G1-S transition and dephosphorylated in late mitosis. Mainly phosphorylated at Ser-23 and Ser-29, by cyclin A-CDK2 and cyclin B-CDK1, respectively during DNA replication and mitosis. Dephosphorylation may require the serine/threonine-protein phosphatase 4. Phosphorylation at Ser-23 and Ser-29 is a prerequisite for further phosphorylation. Becomes hyperphosphorylated on additional residues including Ser-4, Ser-8, Thr-21 and Ser-33 in response to DNA damage. Hyperphosphorylation is mediated by ATM, ATR and PRKDC. Primarily recruited to DNA repair nuclear foci as a hypophosphorylated form it undergoes subsequent hyperphosphorylation, catalyzed by ATR. Hyperphosphorylation is required for RAD51 recruitment to chromatin and efficient DNA repair. Phosphorylation at Thr-21 depends upon RFWD3 presence.PTM DNA damage-induced 'Lys-63'-linked polyubiquitination by PRPF19 mediates ATRIP recruitment to the RPA complex at sites of DNA damage and activation of ATR (PubMed:24332808). Ubiquitinated by RFWD3 at stalled replication forks in response to DNA damage: ubiquitination by RFWD3 does not lead to degradation by the proteasome and promotes removal of the RPA complex from stalled replication forks, promoting homologous recombination (PubMed:26474068).SIMILARITY Belongs to the replication factor A protein 2 family. UniProt P15927 1 EQUAL 270 EQUAL Reactome Database ID Release 83 68457 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68457 Reactome R-HSA-68457 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68457.2 1 RPA3 DNA Replication factor A protein 3 (14kD) RPA14 Replication protein A 14 kDa subunit RP-A RF-A Replication factor-A protein 3 Reactome DB_ID: 68459 UniProt:P35244 RPA3 RPA3 REPA3 RPA14 FUNCTION As part of the heterotrimeric replication protein A complex (RPA/RP-A), binds and stabilizes single-stranded DNA intermediates that form during DNA replication or upon DNA stress. It prevents their reannealing and in parallel, recruits and activates different proteins and complexes involved in DNA metabolism. Thereby, it plays an essential role both in DNA replication and the cellular response to DNA damage (PubMed:9430682). In the cellular response to DNA damage, the RPA complex controls DNA repair and DNA damage checkpoint activation. Through recruitment of ATRIP activates the ATR kinase a master regulator of the DNA damage response (PubMed:24332808). It is required for the recruitment of the DNA double-strand break repair factors RAD51 and RAD52 to chromatin, in response to DNA damage. Also recruits to sites of DNA damage proteins like XPA and XPG that are involved in nucleotide excision repair and is required for this mechanism of DNA repair (PubMed:7697716). Also plays a role in base excision repair (BER), probably through interaction with UNG (PubMed:9765279). Also recruits SMARCAL1/HARP, which is involved in replication fork restart, to sites of DNA damage. May also play a role in telomere maintenance. RPA3 has its own single-stranded DNA-binding activity and may be responsible for polarity of the binding of the complex to DNA (PubMed:19010961). As part of the alternative replication protein A complex, aRPA, binds single-stranded DNA and probably plays a role in DNA repair. Compared to the RPA2-containing, canonical RPA complex, may not support chromosomal DNA replication and cell cycle progression through S-phase. The aRPA may not promote efficient priming by DNA polymerase alpha but could support DNA synthesis by polymerase delta in presence of PCNA and replication factor C (RFC), the dual incision/excision reaction of nucleotide excision repair and RAD51-dependent strand exchange (PubMed:19996105).SUBUNIT Component of the canonical replication protein A complex (RPA), a heterotrimer composed of RPA1, RPA2 and RPA3. Also a component of the aRPA, the alternative replication protein A complex, a trimeric complex similar to the replication protein A complex/RPA but where RPA1 and RPA3 are associated with RPA4 instead of RPA2.PTM Ubiquitinated by RFWD3 at stalled replication forks in response to DNA damage: ubiquitination by RFWD3 does not lead to degradation by the proteasome and promotes removal of the RPA complex from stalled replication forks, promoting homologous recombination (PubMed:26474068).SIMILARITY Belongs to the replication factor A protein 3 family. UniProt P35244 1 EQUAL 121 EQUAL Reactome Database ID Release 83 68459 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68459 Reactome R-HSA-68459 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68459.2 1 Reactome Database ID Release 83 68462 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68462 Reactome R-HSA-68462 11 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68462.11 RPA-ssDNA complex RPA complexed to ssDNA Reactome DB_ID: 176293 1 1 Reactome Database ID Release 83 176293 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176293 Reactome R-HSA-176293 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176293.1 Reactome Database ID Release 83 176175 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176175 Reactome R-HSA-176175 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176175.2 12142537 Pubmed 2002 Fork reversal and ssDNA accumulation at stalled replication forks owing to checkpoint defects Sogo, JM Lopes, M Foiani, M Science 297:599-602 10051570 Pubmed 1999 Nuclear foci of mammalian recombination proteins are located at single-stranded DNA regions formed after DNA damage Raderschall, E Golub, EI Haaf, T Proc Natl Acad Sci U S A 96:1921-6 15833913 Pubmed 2005 Functional uncoupling of MCM helicase and DNA polymerase activities activates the ATR-dependent checkpoint Byun, TS Pacek, M Yee, MC Walter, JC Cimprich, KA Genes Dev 19:1040-52 16387650 Pubmed 2006 Multiple mechanisms control chromosome integrity after replication fork uncoupling and restart at irreparable UV lesions Lopes, M Foiani, M Sogo, JM Mol Cell 21:15-27 12791985 Pubmed 2003 Sensing DNA damage through ATRIP recognition of RPA-ssDNA complexes Zou, L Elledge, SJ Science 300:1542-8 8196638 Pubmed 1994 Human replication protein A binds single-stranded DNA in two distinct complexes Blackwell, LJ Borowiec, James A Mol Cell Biol 14:3993-4001 10373362 Pubmed 1999 Analysis of DNA replication forks encountering a pyrimidine dimer in the template to the leading strand Cordeiro-Stone, M Makhov, AM Zaritskaya, LS Griffith, JD J Mol Biol 289:1207-18 9242902 Pubmed 1997 Replication protein A: a heterotrimeric, single-stranded DNA-binding protein required for eukaryotic DNA metabolism. Wold, MS Annu Rev Biochem 66:61-92 10473346 Pubmed 1999 Replication protein A (RPA): the eukaryotic SSB. Iftode, C Daniely, Y Borowiec, James A Crit Rev Biochem Mol Biol 34:141-80 GENE ONTOLOGY GO:0006260 gene ontology term for cellular process MI MI:0359 LEFT-TO-RIGHT Binding of ATR-ATRIP to the RPA-ssDNA complex ATR kinase activity is stimulated upon binding of the ATR-ATRIP complex to an RPA-ssDNA complex. ATR can subsequently phosphorylate and activate the checkpoint kinase Chk1, allowing further amplification of the checkpoint signal. The ATR and Chk1 kinases then modify a variety of factors that can lead to stabilization of stalled DNA replication forks, inhibition of origin firing, inhibition of cell cycle progression, mobilization of DNA repair factors, and induction of apoptosis. This checkpoint signaling mechanism is highly conserved in eukaryotes, and homologues of ATR and ATRIP are found in such organisms as S. cerevisiae (Mec1 and Ddc2, respectively), S. pombe (rad3 and rad26, respectively), and X. laevis (Xatr and Xatrip, respectively).<p>The ATR (ATM- and rad3-related) kinase is an essential checkpoint factor in human cells. In response to replication stress (i.e., stresses that cause replication fork stalling) or ultraviolet radiation, ATR becomes active and phosphorylates numerous factors involved in the checkpoint response including the checkpoint kinase Chk1. ATR is invariably associated with ATRIP (ATR-interacting protein) in human cells. Depletion of ATRIP by siRNA causes a loss of ATR protein without affecting ATR mRNA levels indicating that complex formation stabilizes the ATR protein. ATRIP is also a substrate for the ATR kinase, but modification of ATRIP does not significantly regulate the recruitment of ATR-ATRIP to sites of damage, the activation of Chk1, or the modification of p53.<p>While the ATR-ATRIP complex binds only poorly to RPA complexed with ssDNA lengths of 30 or 50 nt, binding is significantly enhanced in the presence of a 75 nt ssDNA molecule. Complex formation is primarily mediated by physical interaction between ATRIP and RPA. Multiple elements within the ATRIP molecule can bind to the RPA-ssDNA complex, including residues 1-107 (highest affinity), 218-390, and 390-791 (lowest affinity). Although the full-length ATRIP is unable to bind ssDNA, an internal region (108-390) can weakly bind ssDNA when present in rabbit reticulocyte lysates. ATR can bind to the ssDNA directly independent of RPA, but this binding is inhibited by ATRIP. Upon binding, the ATR kinase becomes activated and can directly phosphorylate substrates such as Rad17. Authored: Borowiec, JA, 2006-02-25 17:40:15 Edited: D'Eustachio, P, 2006-02-25 17:41:28 ATR:ATRIP ATR-ATRIP ATM- and rad3-related (ATR) ATR-interacting protein (ATRIP) Reactome DB_ID: 176269 ATR Serine/threonine-protein kinase ATR ATR_HUMAN Reactome DB_ID: 912443 UniProt:Q13535 ATR ATR FRP1 FUNCTION Serine/threonine protein kinase which activates checkpoint signaling upon genotoxic stresses such as ionizing radiation (IR), ultraviolet light (UV), or DNA replication stalling, thereby acting as a DNA damage sensor. Recognizes the substrate consensus sequence [ST]-Q. Phosphorylates BRCA1, CHEK1, MCM2, RAD17, RPA2, SMC1 and p53/TP53, which collectively inhibit DNA replication and mitosis and promote DNA repair, recombination and apoptosis. Phosphorylates 'Ser-139' of histone variant H2AX at sites of DNA damage, thereby regulating DNA damage response mechanism. Required for FANCD2 ubiquitination. Critical for maintenance of fragile site stability and efficient regulation of centrosome duplication. Positively regulates the restart of stalled replication forks following activation by the KHDC3L-OOEP scaffold complex (By similarity).ACTIVITY REGULATION Serine/threonine-protein kinase activity is directly stimulated by TOPBP1 (PubMed:16530042). ATR kinase activity is also directly activated by ETAA1, independently of TOPBP1 (PubMed:27723720, PubMed:27723717). Activated by DNA and inhibited by BCR-ABL oncogene (PubMed:10597277). Slightly activated by ATRIP (PubMed:14729973). Inhibited by caffeine, wortmannin and LY294002 (PubMed:9766667).SUBUNIT Forms a heterodimer with ATRIP.(PubMed:11721054). Binds to DNA, and to UV-damaged DNA with higher affinity. Interacts with RAD17, MSH2 and HDAC2. Present in a complex containing ATRIP and RPA-coated single-stranded DNA. Present in a complex containing CHD4 and HDAC2. Interacts with EEF1E1, the interaction is enhanced by UV irradiation. Interacts with CLSPN and CEP164. Interacts with TELO2 and TTI1. Interacts with BCR-ABL after genotoxic stress. Interacts with UHRF2; this interaction promotes ATR activation.TISSUE SPECIFICITY Ubiquitous, with highest expression in testis. Isoform 2 is found in pancreas, placenta and liver but not in heart, testis and ovary.PTM Phosphorylated; autophosphorylates in vitro.SIMILARITY Belongs to the PI3/PI4-kinase family. ATM subfamily. UniProt Q13535 1 EQUAL 2644 EQUAL Reactome Database ID Release 83 912443 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=912443 Reactome R-HSA-912443 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-912443.1 1 ATRIP ATRIP monomer ATR interacting protein Reactome DB_ID: 176231 UniProt:Q8WXE1 ATRIP ATRIP AGS1 FUNCTION Required for checkpoint signaling after DNA damage. Required for ATR expression, possibly by stabilizing the protein.SUBUNIT Interacts with ATR (By similarity). Heterodimer with ATR. The heterodimer binds the RPA complex and is then recruited to single-stranded DNA. Interacts with CEP164 (via N-terminus). Interacts with CINP.TISSUE SPECIFICITY Ubiquitous.DOMAIN The EEXXXDDL motif is required for the interaction with catalytic subunit PRKDC and its recruitment to sites of DNA damage.PTM Phosphorylated by ATR.SIMILARITY Belongs to the ATRIP family.CAUTION The gene for this protein is either identical to or adjacent to that of TREX1. Some of the mRNAs that encode ATRIP also encode TREX1 in another reading frame. UniProt Q8WXE1 1 EQUAL 791 EQUAL Reactome Database ID Release 83 176231 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176231 Reactome R-HSA-176231 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176231.1 1 Reactome Database ID Release 83 176269 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176269 Reactome R-HSA-176269 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176269.1 ComplexPortal CPX-3622 ATR:ATRIP:RPA:ssDNA signaling complex ATR-ATRIP-RPA-ssDNA signaling complex Reactome DB_ID: 176281 1 1 Reactome Database ID Release 83 176281 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176281 Reactome R-HSA-176281 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176281.1 Reactome Database ID Release 83 176250 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176250 Reactome R-HSA-176250 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176250.2 10559981 Pubmed 1999 A Rad3-Rad26 complex responds to DNA damage independently of other checkpoint proteins Edwards, RJ Bentley, NJ Carr, AM Nat Cell Biol 1:393-8 15743907 Pubmed 2005 ATRIP binding to replication protein A-single-stranded DNA promotes ATR-ATRIP localization but is dispensable for Chk1 phosphorylation Ball, HL Myers, JS Cortez, D Mol Biol Cell 16:2372-81 8019001 Pubmed 1994 Identification and characterization of new elements involved in checkpoint and feedback controls in fission yeast al-Khodairy, F Fotou, E Sheldrick, KS Griffiths, DJ Lehmann, AR Carr, AM Mol Biol Cell 5:147-60 15451423 Pubmed 2004 ATR-dependent phosphorylation of ATRIP in response to genotoxic stress Itakura, E Umeda, K Sekoguchi, E Takata, H Ohsumi, M Matsuura, A Biochem Biophys Res Commun 323:1197-202 16407120 Pubmed 2006 ATRIP associates with replication protein A-coated ssDNA through multiple interactions Namiki, Y Zou, L Proc Natl Acad Sci U S A 103:580-5 12015327 Pubmed 2002 The role of single-stranded DNA and polymerase alpha in establishing the ATR, Hus1 DNA replication checkpoint You, Z Kong, L Newport, J J Biol Chem 277:27088-93 16327781 Pubmed 2006 ATM- and cell cycle-dependent regulation of ATR in response to DNA double-strand breaks Jazayeri, A Falck, J Lukas, C Bartek, J Smith, GC Lukas, J Jackson, SP Nat Cell Biol 8:37-45 10950868 Pubmed 2000 The checkpoint protein Ddc2, functionally related to S. pombe Rad26, interacts with Mec1 and is regulated by Mec1-dependent phosphorylation in budding yeast. Paciotti, V Clerici, M Lucchini, G Longhese, MP Genes Dev 14:2046-59 15371427 Pubmed 2004 Claspin and the activated form of ATR-ATRIP collaborate in the activation of Chk1 Kumagai, A Kim, SM Dunphy, WG J Biol Chem 279:49599-608 LEFT-TO-RIGHT Recruitment of Rad17-RFC complex to DNA The Rad17-RFC complex is involved in an early stage of the genotoxic stress response. The major function of the protein complex is to load the Rad9-Hus1-Rad1 (9-1-1) complex onto DNA at sites of damage and/or stalled replication forks. This reaction is conceptually similar to the loading of the PCNA sliding clamp onto DNA by RFC. The association of the Rad17-RFC complex with ssDNA or gapped or primed DNA is significantly stimulated by RPA, but not by the heterologous E. coli SSB. Loading of the human 9-1-1 complex onto such DNA templates is also strongly stimulated by cognate RPA, but not yeast RPA. Although Rad17 and Rad9 are substrates of the ATR kinase activity, loading of the Rad17 and 9-1-1 complexes onto DNA occurs independent of ATR.<p>The Rad17-RFC complex is a heteropentamer structurally similar to RFC. The complex contains the four smaller RFC subunits (Rfc2 [p37], Rfc3 [p36], Rfc4 [p40], and Rfc5 [p38]) and the 75 kDa Rad17 subunit in place of the Rfc1 [p140] subunit. The Rad17 complex contains a weak ATPase that is slightly stimulated by primed DNA. Along with binding the 9-1-1 complex and RPA, the Rad17-RFC complex interacts with human MCM7 protein. Each of these interactions is critical for Chk1 activation.<p>The Rad17 subunit is conserved evolutionarily with the protein showing 49% identity at the amino acid level with the S. pombe rad17 protein. Targeted deletion of the N-terminal region of mouse Rad17 leads to embryonic lethality, strongly suggesting that human Rad17 is also essential for long-term viability.<p>Rad17-RFC complex associates with DNA substrates containing ssDNA regions including gapped or primed DNA in an ATP-independent reaction. Loading of the Rad9-Hus1-Rad1 (9-1-1) complex occurs preferentially on DNA substrates containing a 5' recessed end. This contrasts with the loading of PCNA by RFC which preferentially occurs on DNA with 3' recessed ends. Authored: Borowiec, JA, 2006-02-25 17:40:15 Edited: D'Eustachio, P, 2006-02-25 17:41:28 RAD17:RFC Rad17-RFC complex Reactome DB_ID: 176353 RFC5 RFC36 Activator 1 36 kDa subunit (Replication factor C 36 kDa subunit) (A1 36 kDa subunit) (RF-C 36 kDa subunit) (RFC36) Activator 1 36 kDa subunit Replication factor C 36 kDa subunit A1 36 kDa subunit RF-C 36 kDa subunit Replication factor C subunit 5 Reactome DB_ID: 68427 UniProt:P40937 RFC5 RFC5 FUNCTION The elongation of primed DNA templates by DNA polymerase delta and epsilon requires the action of the accessory proteins proliferating cell nuclear antigen (PCNA) and activator 1.SUBUNIT Heterotetramer of subunits RFC2, RFC3, RFC4 and RFC5 that can form a complex either with RFC1 or with RAD17. The former interacts with PCNA in the presence of ATP, while the latter has ATPase activity but is not stimulated by PCNA.SIMILARITY Belongs to the activator 1 small subunits family. UniProt P40937 1 EQUAL 340 EQUAL Reactome Database ID Release 83 68427 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68427 Reactome R-HSA-68427 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68427.2 1 RFC4 RFC37 Activator 1 37 kDa subunit Replication factor C 37 kDa subunit A1 37 kDa subunit RF-C 37 kDa subunit Reactome DB_ID: 68429 UniProt:P35249 RFC4 RFC4 FUNCTION The elongation of primed DNA templates by DNA polymerase delta and epsilon requires the action of the accessory proteins proliferating cell nuclear antigen (PCNA) and activator 1. This subunit may be involved in the elongation of the multiprimed DNA template.SUBUNIT Heterotetramer of subunits RFC2, RFC3, RFC4 and RFC5 that can form a complex either with RFC1 or with RAD17. The former interacts with PCNA in the presence of ATP, while the latter has ATPase activity but is not stimulated by PCNA. Interacts with CNTD1; this interaction facilitates crossover formation (By similarity).MISCELLANEOUS Despite of the presence of a putative ATP-binding motif, this protein does not bind ATP.SIMILARITY Belongs to the activator 1 small subunits family. UniProt P35249 1 EQUAL 363 EQUAL Reactome Database ID Release 83 68429 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68429 Reactome R-HSA-68429 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68429.2 1 RFC3 RFC38 Activator 1 38 kDa subunit Replication factor C 38 kDa subunit A1 38 kDa subunit RF-C 38 kDa subunit Replication factor C subunit 3 Reactome DB_ID: 68431 UniProt:P40938 RFC3 RFC3 FUNCTION The elongation of primed DNA templates by DNA polymerase delta and epsilon requires the action of the accessory proteins proliferating cell nuclear antigen (PCNA) and activator 1.SUBUNIT Heterotetramer of subunits RFC2, RFC3, RFC4 and RFC5 that can form a complex either with RFC1 or with RAD17. The former interacts with PCNA in the presence of ATP, while the latter has ATPase activity but is not stimulated by PCNA. Interacts with CNTD1; this interaction facilitates crossover formation (By similarity).SIMILARITY Belongs to the activator 1 small subunits family. UniProt P40938 1 EQUAL 356 EQUAL Reactome Database ID Release 83 68431 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68431 Reactome R-HSA-68431 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68431.2 1 RAD17 Cell cycle checkpoint protein RAD17 RAD17_HUMAN Reactome DB_ID: 3008665 UniProt:O75943 RAD17 RAD17 R24L FUNCTION Essential for sustained cell growth, maintenance of chromosomal stability, and ATR-dependent checkpoint activation upon DNA damage. Has a weak ATPase activity required for binding to chromatin. Participates in the recruitment of the RAD1-RAD9-HUS1 complex and RHNO1 onto chromatin, and in CHEK1 activation. May also serve as a sensor of DNA replication progression, and may be involved in homologous recombination.SUBUNIT Part of a DNA-binding complex containing RFC2, RFC3, RFC4 and RFC5. Interacts with RAD1 and RAD9 within the RAD1-RAD9-HUS1 complex. Interacts with RAD9B, POLE, SNU13 and MCM7. DNA damage promotes interaction with ATR or ATM and disrupts interaction with the RAD1-RAD9-HUS1 complex.TISSUE SPECIFICITY Overexpressed in various cancer cell lines and in colon carcinoma (at protein level). Isoform 2 and isoform 3 are the most abundant isoforms in non irradiated cells (at protein level). Ubiquitous at low levels. Highly expressed in testis, where it is expressed within the germinal epithelium of the seminiferous tubuli. Weakly expressed in seminomas (testicular tumors).INDUCTION Isoform 1, isoform 3 and isoform 4 are induced by X-ray irradiation.PTM Phosphorylated. Phosphorylation on Ser-646 and Ser-656 is cell cycle-regulated, enhanced by genotoxic stress, and required for activation of checkpoint signaling. Phosphorylation is mediated by ATR upon UV or replication arrest, whereas it may be mediated both by ATR and ATM upon ionizing radiation. Phosphorylation on both sites is required for interaction with RAD1 but dispensable for interaction with RFC3 or RFC4.SIMILARITY Belongs to the rad17/RAD24 family. UniProt O75943 1 EQUAL 681 EQUAL Reactome Database ID Release 83 3008665 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=3008665 Reactome R-HSA-3008665 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-3008665.1 1 RFC2 RFC40 Activator 1 40 kDa subunit Replication factor C 40 kDa subunit A1 40 kDa subunit RF-C 40 kDa subunit Reactome DB_ID: 68433 UniProt:P35250 RFC2 RFC2 FUNCTION The elongation of primed DNA templates by DNA polymerase delta and epsilon requires the action of the accessory proteins proliferating cell nuclear antigen (PCNA) and activator 1. This subunit binds ATP (By similarity).SUBUNIT Heterotetramer of subunits RFC2, RFC3, RFC4 and RFC5 that can form a complex either with RFC1 or with RAD17. The former interacts with PCNA in the presence of ATP, while the latter has ATPase activity but is not stimulated by PCNA. RFC2 also interacts with PRKAR1A; the complex may be involved in cell survival (PubMed:15655353). Interacts with DDX11 (PubMed:18499658).DISEASE RFC2 is located in the Williams-Beuren syndrome (WBS) critical region. WBS results from a hemizygous deletion of several genes on chromosome 7q11.23, thought to arise as a consequence of unequal crossing over between highly homologous low-copy repeat sequences flanking the deleted region (PubMed:11003705).SIMILARITY Belongs to the activator 1 small subunits family. UniProt P35250 1 EQUAL 354 EQUAL Reactome Database ID Release 83 68433 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68433 Reactome R-HSA-68433 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68433.2 1 Reactome Database ID Release 83 176353 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176353 Reactome R-HSA-176353 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176353.1 Rad17-RFC complex bound to DNA Reactome DB_ID: 176204 1 1 Reactome Database ID Release 83 176204 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176204 Reactome R-HSA-176204 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176204.1 Reactome Database ID Release 83 176101 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176101 Reactome R-HSA-176101 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176101.2 14624239 Pubmed 2003 Biochemical characterization of DNA damage checkpoint complexes: clamp loader and clamp complexes with specificity for 5' recessed DNA Ellison, V Stillman, B PLoS Biol 1:E33 15279787 Pubmed 2004 Dial 9-1-1 for DNA damage: the Rad9-Hus1-Rad1 (9-1-1) clamp complex Parrilla-Castellar, ER Arlander, SJ Karnitz, L DNA Repair (Amst) 3:1009-14 14605214 Pubmed 2003 Replication protein A-mediated recruitment and activation of Rad17 complexes Zou, L Liu, D Elledge, SJ Proc Natl Acad Sci U S A 100:13827-32 12578958 Pubmed 2003 Loading of the human 9-1-1 checkpoint complex onto DNA by the checkpoint clamp loader hRad17-replication factor C complex in vitro Bermudez, VP Lindsey-Boltz, LA Cesare, AJ Maniwa, Y Griffith, JD Hurwitz, J Sancar, A Proc Natl Acad Sci U S A 100:1633-8 LEFT-TO-RIGHT Recruitment of the 9-1-1 complex to DNA Recruitment of the Rad9-Hus1-Rad1 complex to DNA The 9-1-1 complex is a heterotrimeric ring-shaped structure that is loaded onto DNA by the Rad17-RFC complex. In vitro studies indicate that loading is preferred onto DNA substrates containing ssDNA gaps that presumably resemble structures found upon replication fork stalling and DNA polymerase/helicase uncoupling. The Rad17-RFC and 9-1-1 complexes are structurally similar to the RFC (replication factor C) clamp loader and PCNA sliding clamp, respectively, and similar mechanisms are thought to be used during loading of the 9-1-1 complex and PCNA. Upon loading, the 9-1-1 complex can recruit Chk1 onto sites of replication fork uncoupling or DNA damage.<p>The purified Rad17 and Rad9-Hus1-Rad1 (9-1-1) complexes can form a stable co-complex in the presence of ATP, using Rad17-Rad9 interactions. From computer modeling studies, the Rad17 subunit of the complex is also proposed to interact with the C-terminus of Rad1, p36 with the C-terminus of Hus1, and p38 with the C-terminus of Rad9. A major known function of the 9-1-1 complex is to recruit Chk1 to stalled replication forks for activation by ATR. However, the presence of the 9-1-1 complex also alters the ability of Rad17 to become phosphorylated, perhaps suggesting that 9-1-1 may regulate the recruiment of additional ATR substrates. The 9-1-1 complex has also been found to interact with base excision repair factors human DNA polymerase beta, flap endonuclease FEN1, and the S. pombe MutY homolog (SpMYH), indicating that 9-1-1 also plays a direct role in DNA repair. Authored: Borowiec, JA, 2006-02-25 17:40:15 Edited: D'Eustachio, P, 2006-02-25 17:41:28 9-1-1 complex RAD9:HUS1:RAD1 Rad9-Hus1-Rad1 complex Reactome DB_ID: 176312 RAD1 Reactome DB_ID: 176382 UniProt:O60671 RAD1 RAD1 REC1 FUNCTION Component of the 9-1-1 cell-cycle checkpoint response complex that plays a major role in DNA repair (PubMed:10846170, PubMed:10884395). The 9-1-1 complex is recruited to DNA lesion upon damage by the RAD17-replication factor C (RFC) clamp loader complex (PubMed:12578958). Acts then as a sliding clamp platform on DNA for several proteins involved in long-patch base excision repair (LP-BER) (PubMed:15871698). The 9-1-1 complex stimulates DNA polymerase beta (POLB) activity by increasing its affinity for the 3'-OH end of the primer-template and stabilizes POLB to those sites where LP-BER proceeds; endonuclease FEN1 cleavage activity on substrates with double, nick, or gap flaps of distinct sequences and lengths; and DNA ligase I (LIG1) on long-patch base excision repair substrates (PubMed:15314187, PubMed:15556996, PubMed:15871698). The 9-1-1 complex is necessary for the recruitment of RHNO1 to sites of double-stranded breaks (DSB) occurring during the S phase (PubMed:21659603). Isoform 1 possesses 3'-&gt;5' double stranded DNA exonuclease activity (PubMed:9660799).SUBUNIT Component of the toroidal 9-1-1 (RAD9-RAD1-HUS1) complex, composed of RAD9A, RAD1 and HUS1 (PubMed:10846170, PubMed:10884395). The 9-1-1 complex associates with LIG1, POLB, FEN1, RAD17, HDAC1, RPA1 and RPA2 (PubMed:10846170, PubMed:10884395, PubMed:15314187, PubMed:15556996, PubMed:15871698, PubMed:15897895, PubMed:16216273). The 9-1-1 complex associates with the RAD17-RFC complex (PubMed:12578958). RAD1 interacts with POLB, FEN1, HUS1, HUS1B, RAD9A and RAD9B (PubMed:10359610, PubMed:10777662, PubMed:11944979, PubMed:14500360, PubMed:14611806, PubMed:15314187, PubMed:15556996, PubMed:16216273). Interacts with DNAJC7 (PubMed:11573955).TISSUE SPECIFICITY Expressed in testis, uterus, bladder, spleen, ovaries, lung, brain and muscle (at protein level).SIMILARITY Belongs to the rad1 family. UniProt O60671 1 EQUAL 282 EQUAL Reactome Database ID Release 83 176382 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176382 Reactome R-HSA-176382 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176382.1 1 Converted from EntitySet in Reactome RAD9 Reactome DB_ID: 176222 RAD9A Reactome DB_ID: 176372 UniProt:Q99638 RAD9A RAD9A FUNCTION Component of the 9-1-1 cell-cycle checkpoint response complex that plays a major role in DNA repair. The 9-1-1 complex is recruited to DNA lesion upon damage by the RAD17-replication factor C (RFC) clamp loader complex. Acts then as a sliding clamp platform on DNA for several proteins involved in long-patch base excision repair (LP-BER). The 9-1-1 complex stimulates DNA polymerase beta (POLB) activity by increasing its affinity for the 3'-OH end of the primer-template and stabilizes POLB to those sites where LP-BER proceeds; endonuclease FEN1 cleavage activity on substrates with double, nick, or gap flaps of distinct sequences and lengths; and DNA ligase I (LIG1) on long-patch base excision repair substrates. The 9-1-1 complex is necessary for the recruitment of RHNO1 to sites of double-stranded breaks (DSB) occurring during the S phase. RAD9A possesses 3'-&gt;5' double stranded DNA exonuclease activity. Its phosphorylation by PRKCD may be required for the formation of the 9-1-1 complex.SUBUNIT Component of the toroidal 9-1-1 (RAD9-RAD1-HUS1) complex, composed of RAD9A, RAD1 and HUS1. The 9-1-1 complex associates with LIG1, POLB, FEN1, RAD17, HDAC1, RPA1 and RPA2. The 9-1-1 complex associates with the RAD17-RFC complex. RAD9A interacts with BCL2L1, FEN1, PRKCD, RAD9B, HUS1, RAD1, ABL1, RPA1, ATAD5 and RPA2. Interacts with DNAJC7 and RHNO1.PTM Constitutively phosphorylated on serine and threonine amino acids in absence of DNA damage. Hyperphosphorylated by PRKCD and ABL1 upon DNA damage. Its phosphorylation by PRKCD may be required for the formation of the 9-1-1 complex.SIMILARITY Belongs to the rad9 family. UniProt Q99638 1 EQUAL 391 EQUAL Reactome Database ID Release 83 176372 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176372 Reactome R-HSA-176372 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176372.1 RAD9B Reactome DB_ID: 176325 UniProt:Q6WBX8 RAD9B RAD9B SUBUNIT Interacts with HUS1, HUS1B, RAD1, RAD9A and RAD17.TISSUE SPECIFICITY Expressed in testis and skeletal muscle.SIMILARITY Belongs to the rad9 family. UniProt Q6WBX8 1 EQUAL 426 EQUAL Reactome Database ID Release 83 176325 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176325 Reactome R-HSA-176325 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176325.1 Reactome Database ID Release 83 176222 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176222 Reactome R-HSA-176222 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176222.1 1 HUS1 Reactome DB_ID: 176374 UniProt:O60921 HUS1 HUS1 FUNCTION Component of the 9-1-1 cell-cycle checkpoint response complex that plays a major role in DNA repair. The 9-1-1 complex is recruited to DNA lesion upon damage by the RAD17-replication factor C (RFC) clamp loader complex. Acts then as a sliding clamp platform on DNA for several proteins involved in long-patch base excision repair (LP-BER). The 9-1-1 complex stimulates DNA polymerase beta (POLB) activity by increasing its affinity for the 3'-OH end of the primer-template and stabilizes POLB to those sites where LP-BER proceeds; endonuclease FEN1 cleavage activity on substrates with double, nick, or gap flaps of distinct sequences and lengths; and DNA ligase I (LIG1) on long-patch base excision repair substrates. The 9-1-1 complex is necessary for the recruitment of RHNO1 to sites of double-stranded breaks (DSB) occurring during the S phase.SUBUNIT Component of the toroidal 9-1-1 (RAD9-RAD1-HUS1) complex, composed of RAD9A, RAD1 and HUS1. The 9-1-1 complex associates with LIG1, POLB, FEN1, RAD17, HDAC1, RPA1 and RPA2. The 9-1-1 complex associates with the RAD17-RFC complex. HUS1 interacts with POLB, HDAC1, FEN1, PCNA, RAD1, RAD9A and RAD9B. HUS1 does not interact with RAD17. Interacts with DNAJC7.TISSUE SPECIFICITY Ubiquitous.SIMILARITY Belongs to the HUS1 family. UniProt O60921 1 EQUAL 280 EQUAL Reactome Database ID Release 83 176374 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176374 Reactome R-HSA-176374 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176374.1 1 Reactome Database ID Release 83 176312 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176312 Reactome R-HSA-176312 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176312.1 Rad9-Hus1-Rad1 bound to DNA Reactome DB_ID: 176256 1 1 Reactome Database ID Release 83 176256 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176256 Reactome R-HSA-176256 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176256.1 ACTIVATION GENE ONTOLOGY GO:0003689 gene ontology term for cellular function MI MI:0355 Same Catalyst Activity Reactome Database ID Release 83 176122 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176122 Reactome Database ID Release 83 176264 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176264 Reactome R-HSA-176264 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176264.2 15210332 Pubmed 2004 The PCNA-RFC families of DNA clamps and clamp loaders Majka, J Burgers, PM Prog Nucleic Acid Res Mol Biol 78:227-60 12237462 Pubmed 2002 Molecular modeling-based analysis of interactions in the RFC-dependent clamp-loading process Venclovas, C Colvin, ME Thelen, MP Protein Sci 11:2403-16 8943031 Pubmed 1996 A human homolog of the Schizosaccharomyces pombe rad9+ checkpoint control gene Lieberman, HB Hopkins, KM Nass, M Demetrick, D Davey, S Proc Natl Acad Sci U S A 93:13890-5 14500360 Pubmed 2003 Expression of mammalian paralogues of HRAD9 and Mrad9 checkpoint control genes in normal and cancerous testicular tissue Hopkins, KM Wang, X Berlin, A Hang, H Thaker, HM Lieberman, HB Cancer Res 63:5291-8 10777662 Pubmed 2000 Physical interactions among human checkpoint control proteins HUS1p, RAD1p, and RAD9p, and implications for the regulation of cell cycle progression Hang, H Lieberman, HB Genomics 65:24-33 LEFT-TO-RIGHT Loading of claspin onto DNA during replication origin firing Claspin is loaded onto DNA replication origins during replication initiation. Studies in Xenopus egg extracts indicate claspin loading requires the presence of Cdc45, a factor that promotes the initial unwinding of the origin DNA in the presence of Cdk2. This step is followed by RPA binding which is a prerequisite for recruitment of PCNA and DNA polymerases alpha and delta. As RPA is not required for claspin binding, it is postulated that claspin binds at the time of initial origin unwinding but prior to the initiation of DNA synthesis. Claspin would then continue to associate with replication fork machinery where it can serve as a checkpoint sensor protein. Even though associated with the replication fork, claspin is not an essential DNA replication factor.<p>Studies of Xenopus claspin indicate that it can physically associate with cognate Cdc45, DNA polymerase epsilon, RPA, RFC, and Rad17-RFC on chromatin. Studies of purified human claspin indicate that it binds with high affinity to branched (or forked) DNA structures that resemble stalled replication forks. Electron microscopy of these complexes indicates that claspin binds as a ring-like structure near the branch. The protein is hypothesized to encircle the DNA at these sites. Authored: Borowiec, JA, 2006-02-25 17:40:15 Edited: D'Eustachio, P, 2006-02-25 17:41:28 CLSPN Claspin Reactome DB_ID: 176282 UniProt:Q9HAW4 CLSPN CLSPN FUNCTION Required for checkpoint mediated cell cycle arrest in response to inhibition of DNA replication or to DNA damage induced by both ionizing and UV irradiation (PubMed:12766152, PubMed:15190204, PubMed:15707391, PubMed:16123041). Adapter protein which binds to BRCA1 and the checkpoint kinase CHEK1 and facilitates the ATR-dependent phosphorylation of both proteins (PubMed:12766152, PubMed:15707391, PubMed:15096610, PubMed:16123041). Also required to maintain normal rates of replication fork progression during unperturbed DNA replication. Binds directly to DNA, with particular affinity for branched or forked molecules and interacts with multiple protein components of the replisome such as the MCM2-7 complex and TIMELESS (PubMed:15226314, PubMed:35585232, PubMed:34694004). Important for initiation of DNA replication, recruits kinase CDC7 to phosphorylate MCM2-7 components (PubMed:27401717).SUBUNIT Interacts (phosphorylation-dependent) with CHEK1; regulates CLSPN function in checkpoint for DNA damage and replication (PubMed:12766152, PubMed:15707391, PubMed:16963448). Interacts with ATR and RAD9A and these interactions are slightly reduced during checkpoint activation (PubMed:12766152). Interacts with BRCA1 and this interaction increases during checkpoint activation (PubMed:15096610). Interacts with TIMELESS; the interaction is required for leading-strand replication (PubMed:17141802, PubMed:35585232, PubMed:34700328, PubMed:34694004). Associates with the MCM2-7 complex and other replisome factors (PubMed:34700328, PubMed:34694004, PubMed:27401717). Interacts (via the acidic patch) with CDC7; the interaction is required for phosphorylation of MCM proteins and CLASPIN by CDC7 (PubMed:27401717). Interacts with PCNA (PubMed:27401717). Interacts with FZR1 (PubMed:18662541).INDUCTION Expression peaks at S/G2 phases of the cell cycle.DOMAIN The C-terminus of the protein contains 3 potential CHEK1-binding motifs (CKB motifs). Potential phosphorylation sites within CKB motif 1 and CKB motif 2 are required for interaction with CHEK1.DOMAIN The acidic patch region is required for normal DNA replication. Interacts with the N-terminal segments and inhibits binding to DNA and PCNA. Mediates the interaction with the kinase CDC7 as well as some replisome factors and DNA polymerases.PTM Phosphorylated. Undergoes ATR-dependent phosphorylation by CHEK1 during activation of DNA replication or damage checkpoints. Phosphorylation by CSNK1G1/CK1 promotes CHEK1 binding (PubMed:12766152, PubMed:15096610, PubMed:16963448, PubMed:21680713). Phosphorylated by CDC7 during DNA replication, phosphorylation inhibits interaction between the acidic patch and N-terminal segments leading to increased binding to DNA and PCNA (PubMed:27401717).PTM Ubiquitinated by the anaphase promoting complex/cyclosome (APC/C) during G1 phase, leading to its degradation by the proteasome. Ubiquitination is mediated via its interaction with FZR1/CDH1. Following DNA damage, it is deubiquitinated by USP28 in G2 phase, preventing its degradation.PTM Proteolytically cleaved by caspase-7 (CASP7) in response to apoptosis, leading to its inactivation.SIMILARITY Belongs to the claspin family. UniProt Q9HAW4 1 EQUAL 1339 EQUAL Reactome Database ID Release 83 176282 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176282 Reactome R-HSA-176282 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176282.1 CDK:DDK:MCM10:active pre-replicative complex:CDC45 Reactome DB_ID: 68564 CDC45 Cdc45 CDC45-related protein PORC-PI-1 Reactome DB_ID: 68563 UniProt:O75419 CDC45 CDC45 CDC45L CDC45L2 UNQ374/PRO710 FUNCTION Required for initiation of chromosomal DNA replication. Core component of CDC45-MCM-GINS (CMG) helicase, the molecular machine that unwinds template DNA during replication, and around which the replisome is built.SUBUNIT Component of the CMG helicase complex, a hexameric ring of related MCM2-7 subunits stabilized by CDC45 and the tetrameric GINS complex (PubMed:34700328, PubMed:34694004, PubMed:32453425). Associated with ORC2. Interacts with HELB (PubMed:25933514).TISSUE SPECIFICITY Widely expressed, highest levels are found in adult testis and thymus and in fetal liver.DEVELOPMENTAL STAGE Transcript peaks at G1-S transition, but total protein remains constant throughout the cell cycle. Expressed in multiple tissues during embryogenesis, including neural crest-derived structures.SIMILARITY Belongs to the CDC45 family. UniProt O75419 1 EQUAL 566 EQUAL Reactome Database ID Release 83 68563 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68563 Reactome R-HSA-68563 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68563.2 1 CDK:DDK:MCM10:active pre-replicative complex Reactome DB_ID: 68561 MCM10:active pre-replicative complex Reactome DB_ID: 156564 MCM10 Mcm10 Reactome DB_ID: 68403 UniProt:Q7L590 MCM10 MCM10 PRO2249 FUNCTION Acts as a replication initiation factor that brings together the MCM2-7 helicase and the DNA polymerase alpha/primase complex in order to initiate DNA replication. Additionally, plays a role in preventing DNA damage during replication. Key effector of the RBBP6 and ZBTB38-mediated regulation of DNA-replication and common fragile sites stability; acts as a direct target of transcriptional repression by ZBTB38 (PubMed:24726359).SUBUNIT Self-associates (By similarity). Interacts with ORC2. May interact with MCM2 and MCM6. Interacts with the DNA polymerase alpha subunit POLA1. Interacts with RECQL4; this interaction regulates RECQL4 unwinding activity. Interacts with WDHD1.DEVELOPMENTAL STAGE Expression is cell cycle regulated. Expression increases at the G1/S-boundary. Expression decreases in late M phase, remains low during G(1) phase, and starts to accumulate at the onset of S phase.DOMAIN Each zinc finger-like domain binds a zinc ion and is involved in both ssDNA and dsDNA binding, as is the OB-fold domain.DOMAIN The N-terminal domain mediates homodimerization.SIMILARITY Belongs to the MCM10 family. UniProt Q7L590 1 EQUAL 875 EQUAL Reactome Database ID Release 83 68403 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68403 Reactome R-HSA-68403 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68403.2 1 active pre-replicative complex Reactome DB_ID: 156562 MCM2-7 Reactome DB_ID: 68558 MCM2:MCM4:MCM6:MCM7 Reactome DB_ID: 9757255 MCM2 Mcm2 DNA replication licensing factor MCM2 Nuclear protein BM28 Reactome DB_ID: 68557 UniProt:P49736 MCM2 MCM2 BM28 CCNL1 CDCL1 KIAA0030 FUNCTION Acts as component of the MCM2-7 complex (MCM complex) which is the replicative helicase essential for 'once per cell cycle' DNA replication initiation and elongation in eukaryotic cells. Core component of CDC45-MCM-GINS (CMG) helicase, the molecular machine that unwinds template DNA during replication, and around which the replisome is built (PubMed:32453425, PubMed:34694004, PubMed:34700328, PubMed:35585232). The active ATPase sites in the MCM2-7 ring are formed through the interaction surfaces of two neighboring subunits such that a critical structure of a conserved arginine finger motif is provided in trans relative to the ATP-binding site of the Walker A box of the adjacent subunit. The six ATPase active sites, however, are likely to contribute differentially to the complex helicase activity (PubMed:32453425). Required for the entry in S phase and for cell division (PubMed:8175912). Plays a role in terminally differentiated hair cells development of the cochlea and induces cells apoptosis (PubMed:26196677).SUBUNIT Component of the MCM2-7 complex (PubMed:9305914, PubMed:16899510, PubMed:17296731). The complex forms a toroidal hexameric ring with the proposed subunit order MCM2-MCM6-MCM4-MCM7-MCM3-MCM5 (PubMed:9305914, PubMed:16899510, PubMed:17296731, PubMed:34700328, PubMed:34694004, PubMed:32453425). Component of the CMG helicase complex, a hexameric ring of related MCM2-7 subunits stabilized by CDC45 and the tetrameric GINS complex (PubMed:34700328, PubMed:34694004, PubMed:32453425). Interacts with DBF4 (By similarity). Interacts with KAT7 (PubMed:16387653). May interact with MCM10 (PubMed:11095689). Component of the replisome complex composed of at least DONSON, MCM2, MCM7, PCNA and TICRR (PubMed:28191891). Forms a co-chaperone complex with DNAJC9 and histone H3.3-H4 heterodimers (PubMed:33857403). Within the complex, interacts (via N-terminus) with DNAJC9 (via C-terminus); the interaction is histone-dependent (PubMed:33857403). Interacts with histones H3.1 and H3.3 (PubMed:33857403).PTM Phosphorylated on Ser-108 by ATR in proliferating cells. Ser-108 proliferation is increased by genotoxic agents. Ser-40 is mediated by the CDC7-DBF4 and CDC7-DBF4B complexes, while Ser-53 phosphorylation is only mediated by the CDC7-DBF4 complex. Phosphorylation by the CDC7-DBF4 complex during G1/S phase is required for the initiation of DNA replication.MISCELLANEOUS Early fractionation of eukaryotic MCM proteins yielded a variety of dimeric, trimeric and tetrameric complexes with unclear biological significance. Specifically a MCM467 subcomplex is shown to have in vitro helicase activity which is inhibited by the MCM2 subunit. The MCM2-7 hexamer is the proposed physiological active complex.SIMILARITY Belongs to the MCM family. UniProt P49736 2 EQUAL 904 EQUAL Reactome Database ID Release 83 68557 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68557 Reactome R-HSA-68557 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68557.1 1 MCM4:MCM6:MCM7 Mcm4,6,7 complex Mcm4:Mcm6:Mcm7 replicative helicase Reactome DB_ID: 69018 MCM4 Mcm4 DNA replication licensing factor MCM4 CDC21 homolog P1-CDC21 Reactome DB_ID: 68549 UniProt:P33991 MCM4 MCM4 CDC21 FUNCTION Acts as component of the MCM2-7 complex (MCM complex) which is the replicative helicase essential for 'once per cell cycle' DNA replication initiation and elongation in eukaryotic cells. Core component of CDC45-MCM-GINS (CMG) helicase, the molecular machine that unwinds template DNA during replication, and around which the replisome is built (PubMed:32453425, PubMed:34694004, PubMed:34700328, PubMed:35585232, PubMed:16899510, PubMed:25661590, PubMed:9305914). The active ATPase sites in the MCM2-7 ring are formed through the interaction surfaces of two neighboring subunits such that a critical structure of a conserved arginine finger motif is provided in trans relative to the ATP-binding site of the Walker A box of the adjacent subunit. The six ATPase active sites, however, are likely to contribute differentially to the complex helicase activity (PubMed:32453425, PubMed:16899510, PubMed:25661590, PubMed:9305914).SUBUNIT Component of the MCM2-7 complex (PubMed:16899510, PubMed:9305914). The complex forms a toroidal hexameric ring with the proposed subunit order MCM2-MCM6-MCM4-MCM7-MCM3-MCM5 (PubMed:16899510, PubMed:9305914, PubMed:32453425). Component of the CMG helicase complex, a hexameric ring of related MCM2-7 subunits stabilized by CDC45 and the tetrameric GINS complex (PubMed:34700328, PubMed:34694004, PubMed:32453425). Interacts with MCMBP (PubMed:17296731).PTM Sumoylated; SUMO2 modified in response to stress caused by inhibition of proteasome activity (in vitro).MISCELLANEOUS Early fractionation of eukaryotic MCM proteins yielded a variety of dimeric, trimeric and tetrameric complexes with unclear biological significance. Specifically a MCM467 subcomplex is shown to have in vitro helicase activity which is inhibited by the MCM2 subunit. The MCM2-7 hexamer is the proposed physiological active complex.SIMILARITY Belongs to the MCM family. UniProt P33991 2 EQUAL 863 EQUAL Reactome Database ID Release 83 68549 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68549 Reactome R-HSA-68549 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68549.1 1 MCM6 Mcm6 DNA replication licensing factor MCM6 P105MCM Reactome DB_ID: 68553 UniProt:Q14566 MCM6 MCM6 FUNCTION Acts as component of the MCM2-7 complex (MCM complex) which is the replicative helicase essential for 'once per cell cycle' DNA replication initiation and elongation in eukaryotic cells. Core component of CDC45-MCM-GINS (CMG) helicase, the molecular machine that unwinds template DNA during replication, and around which the replisome is built (PubMed:32453425, PubMed:34694004, PubMed:34700328, PubMed:35585232, PubMed:16899510, PubMed:9305914). The active ATPase sites in the MCM2-7 ring are formed through the interaction surfaces of two neighboring subunits such that a critical structure of a conserved arginine finger motif is provided in trans relative to the ATP-binding site of the Walker A box of the adjacent subunit. The six ATPase active sites, however, are likely to contribute differentially to the complex helicase activity (PubMed:32453425).SUBUNIT Component of the MCM2-7 complex (PubMed:16899510, PubMed:17296731, PubMed:9305914). The complex forms a toroidal hexameric ring with the proposed subunit order MCM2-MCM6-MCM4-MCM7-MCM3-MCM5 (PubMed:16899510, PubMed:17296731, PubMed:9305914, PubMed:32453425, PubMed:34700328, PubMed:34694004). Component of the CMG helicase complex, a hexameric ring of related MCM2-7 subunits stabilized by CDC45 and the tetrameric GINS complex (PubMed:34700328, PubMed:34694004, PubMed:32453425). May interact with MCM10 (PubMed:11095689). Interacts with TIPIN (PubMed:17116885). Interacts with CDT1 (PubMed:20202939). Interacts with MCMBP (PubMed:17296731). Interacts with DDI2 (PubMed:29290612).PTM O-glycosylated (O-GlcNAcylated), in a cell cycle-dependent manner.POLYMORPHISM Intronic variations in MCM6 upstream from the LCT gene are associated with adult-type hypolactasia [MIM:223100] leading to lactose intolerance, or with lactase persistance. Lactose intolerance is a normal physiological phenomenon caused by developmental down-regulation of lactase activity during childhood or early adulthood. A non-coding variation in MCM6 affects the transcriptional regulation of the LCT gene resulting in down-regulation of lactase activity. However, the majority of Northern Europeans and some African populations have the ability to maintain lactase activity and digest lactose throughout life (lactase persistence).MISCELLANEOUS Early fractionation of eukaryotic MCM proteins yielded a variety of dimeric, trimeric and tetrameric complexes with unclear biological significance. Specifically a MCM467 subcomplex is shown to have in vitro helicase activity which is inhibited by the MCM2 subunit. The MCM2-7 hexamer is the proposed physiological active complex.SIMILARITY Belongs to the MCM family. UniProt Q14566 1 EQUAL 821 EQUAL Reactome Database ID Release 83 68553 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68553 Reactome R-HSA-68553 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68553.1 1 MCM7 Mcm7 DNA replication licensing factor MCM7 CDC47 homolog P1.1-MCM3 Reactome DB_ID: 68555 UniProt:P33993 MCM7 MCM7 CDC47 MCM2 FUNCTION Acts as component of the MCM2-7 complex (MCM complex) which is the replicative helicase essential for 'once per cell cycle' DNA replication initiation and elongation in eukaryotic cells. Core component of CDC45-MCM-GINS (CMG) helicase, the molecular machine that unwinds template DNA during replication, and around which the replisome is built (PubMed:32453425, PubMed:34694004, PubMed:34700328, PubMed:35585232, PubMed:25661590, PubMed:9305914). The active ATPase sites in the MCM2-7 ring are formed through the interaction surfaces of two neighboring subunits such that a critical structure of a conserved arginine finger motif is provided in trans relative to the ATP-binding site of the Walker A box of the adjacent subunit. The six ATPase active sites, however, are likely to contribute differentially to the complex helicase activity (PubMed:32453425). Required for S-phase checkpoint activation upon UV-induced damage.SUBUNIT Component of the MCM2-7 complex (PubMed:9305914, PubMed:16899510, PubMed:17296731). The complex forms a toroidal hexameric ring with the proposed subunit order MCM2-MCM6-MCM4-MCM7-MCM3-MCM5 (PubMed:9305914, PubMed:16899510, PubMed:17296731, PubMed:32453425). Component of the CMG helicase complex, a hexameric ring of related MCM2-7 subunits stabilized by CDC45 and the tetrameric GINS complex (PubMed:34700328, PubMed:34694004, PubMed:32453425). Interacts with the ATR-ATRIP complex and with RAD17 (PubMed:15210935, PubMed:15538388). Interacts with TIPIN (PubMed:17116885). Interacts with MCMBP (PubMed:17296731). Interacts with ANKRD17 (PubMed:23711367). Component of the replisome complex composed of at least DONSON, MCM2, MCM7, PCNA and TICRR (PubMed:28191891).PTM O-glycosylated (O-GlcNAcylated), in a cell cycle-dependent manner.PTM Ubiquitinated by ECS(LRR1) E3 ubiquitin-protein ligase complex when forks converge following formation of DNA interstrand cross-links. During mitosis, ubiquitinated by TRAIP when forks converge following formation of DNA interstrand cross-links (By similarity). Short ubiquitin chains on MCM7 promote recruitment of DNA glycosylase NEIL3 (By similarity). If the interstrand cross-link cannot be cleaved by NEIL3, the ubiquitin chains continue to grow on MCM7, promoting the unloading of the CMG helicase complex by the VCP/p97 ATPase (By similarity).MISCELLANEOUS Early fractionation of eukaryotic MCM proteins yielded a variety of dimeric, trimeric and tetrameric complexes with unclear biological significance. Specifically a MCM467 subcomplex is shown to have in vitro helicase activity which is inhibited by the MCM2 subunit. The MCM2-7 hexamer is the proposed physiological active complex.SIMILARITY Belongs to the MCM family. UniProt P33993 2 EQUAL 719 EQUAL Reactome Database ID Release 83 68555 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68555 Reactome R-HSA-68555 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68555.1 1 Reactome Database ID Release 83 69018 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=69018 Reactome R-HSA-69018 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-69018.2 1 Reactome Database ID Release 83 9757255 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=9757255 Reactome R-HSA-9757255 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-9757255.1 1 MCM3:MCM5 Reactome DB_ID: 9757259 MCM5 Mcm5 DNA replication licensing factor MCM5 CDC46 homolog P1-CDC46 Reactome DB_ID: 68551 UniProt:P33992 MCM5 MCM5 CDC46 FUNCTION Acts as component of the MCM2-7 complex (MCM complex) which is the replicative helicase essential for 'once per cell cycle' DNA replication initiation and elongation in eukaryotic cells. Core component of CDC45-MCM-GINS (CMG) helicase, the molecular machine that unwinds template DNA during replication, and around which the replisome is built (PubMed:32453425, PubMed:34694004, PubMed:34700328, PubMed:35585232, PubMed:16899510). The active ATPase sites in the MCM2-7 ring are formed through the interaction surfaces of two neighboring subunits such that a critical structure of a conserved arginine finger motif is provided in trans relative to the ATP-binding site of the Walker A box of the adjacent subunit. The six ATPase active sites, however, are likely to contribute differentially to the complex helicase activity (PubMed:32453425).SUBUNIT Component of the MCM2-7 complex (PubMed:17296731, PubMed:16899510). The complex forms a toroidal hexameric ring with the proposed subunit order MCM2-MCM6-MCM4-MCM7-MCM3-MCM5 (PubMed:17296731, PubMed:16899510, PubMed:32453425). Component of the CMG helicase complex, a hexameric ring of related MCM2-7 subunits stabilized by CDC45 and the tetrameric GINS complex (PubMed:34700328, PubMed:34694004, PubMed:32453425). Interacts with ANKRD17 (PubMed:23711367). Interacts with MCMBP (PubMed:17296731). Interacts with TONSL; the interaction is direct (PubMed:26527279).MISCELLANEOUS Early fractionation of eukaryotic MCM proteins yielded a variety of dimeric, trimeric and tetrameric complexes with unclear biological significance. The MCM2-7 hexamer is the proposed physiological active complex.SIMILARITY Belongs to the MCM family. UniProt P33992 1 EQUAL 734 EQUAL Reactome Database ID Release 83 68551 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68551 Reactome R-HSA-68551 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68551.1 1 MCM3 Mcm3 DNA replication licensing factor MCM3 DNA polymerase alpha holoenzyme-associated protein P1 RLF beta subunit P102 protein P1-MCM3 Reactome DB_ID: 68546 UniProt:P25205 MCM3 MCM3 FUNCTION Acts as component of the MCM2-7 complex (MCM complex) which is the replicative helicase essential for 'once per cell cycle' DNA replication initiation and elongation in eukaryotic cells. Core component of CDC45-MCM-GINS (CMG) helicase, the molecular machine that unwinds template DNA during replication, and around which the replisome is built (PubMed:32453425, PubMed:34694004, PubMed:34700328, PubMed:35585232). The active ATPase sites in the MCM2-7 ring are formed through the interaction surfaces of two neighboring subunits such that a critical structure of a conserved arginine finger motif is provided in trans relative to the ATP-binding site of the Walker A box of the adjacent subunit. The six ATPase active sites, however, are likely to contribute differentially to the complex helicase activity (PubMed:32453425). Required for the entry in S phase and for cell division (Probable).SUBUNIT Component of the MCM2-7 complex (PubMed:16899510, PubMed:17296731). The complex forms a toroidal hexameric ring with the proposed subunit order MCM2-MCM6-MCM4-MCM7-MCM3-MCM5 (PubMed:16899510, PubMed:17296731, PubMed:34700328, PubMed:34694004, PubMed:32453425). Component of the CMG helicase complex, a hexameric ring of related MCM2-7 subunits stabilized by CDC45 and the tetrameric GINS complex (PubMed:34700328, PubMed:34694004, PubMed:32453425). Associated with the replication-specific DNA polymerase alpha (By similarity). Interacts with MCMBP (PubMed:17296731). Interacts with ANKRD17 (PubMed:23711367). Interacts with MCM3AP isoform MCM3AP; this interaction leads to MCM3 acetylation (PubMed:9712829, PubMed:11258703, PubMed:12226073).PTM Acetylated by MCM3AP.PTM O-glycosylated (O-GlcNAcylated), in a cell cycle-dependent manner.MISCELLANEOUS Early fractionation of eukaryotic MCM proteins yielded a variety of dimeric, trimeric and tetrameric complexes with unclear biological significance. The MCM2-7 hexamer is the proposed physiological active complex.SIMILARITY Belongs to the MCM family. UniProt P25205 2 EQUAL 808 EQUAL Reactome Database ID Release 83 68546 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68546 Reactome R-HSA-68546 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68546.1 1 Reactome Database ID Release 83 9757259 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=9757259 Reactome R-HSA-9757259 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-9757259.1 1 Reactome Database ID Release 83 68558 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68558 Reactome R-HSA-68558 4 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68558.4 ComplexPortal CPX-2940 1 CDC6:ORC:origin complex Reactome DB_ID: 68543 ORC:origin of replication Reactome DB_ID: 68540 Orc2 associated with MCM8 Reactome DB_ID: 176970 MCM8 DNA helicase MCM8 MCM8_HUMAN Reactome DB_ID: 3006646 UniProt:Q9UJA3 MCM8 MCM8 C20orf154 FUNCTION Component of the MCM8-MCM9 complex, a complex involved in the repair of double-stranded DNA breaks (DBSs) and DNA interstrand cross-links (ICLs) by homologous recombination (HR) (PubMed:23401855). Required for DNA resection by the MRE11-RAD50-NBN/NBS1 (MRN) complex by recruiting the MRN complex to the repair site and by promoting the complex nuclease activity (PubMed:26215093). Probably by regulating the localization of the MNR complex, indirectly regulates the recruitment of downstream effector RAD51 to DNA damage sites including DBSs and ICLs (PubMed:23401855). The MCM8-MCM9 complex is dispensable for DNA replication and S phase progression (PubMed:23401855). However, may play a non-essential for DNA replication: may be involved in the activation of the prereplicative complex (pre-RC) during G(1) phase by recruiting CDC6 to the origin recognition complex (ORC) (PubMed:15684404). Probably by regulating HR, plays a key role during gametogenesis (By similarity). Stabilizes MCM9 protein (PubMed:23401855, PubMed:26215093).SUBUNIT Component of the MCM8-MCM9 complex, which forms a hexamer composed of MCM8 and MCM9 (PubMed:23401855, PubMed:26300262). Interacts with the DNA mismatch repair (MMR) complex composed at least of MSH2, MSH3, MSH6, PMS1 and MLH1 (PubMed:26300262). Interacts with RAD51; the interaction recruits RAD51 to DNA damage sites (PubMed:23401855). Interacts with the MRN complex composed of MRE11, RAD50 and NBN/NBS1 (PubMed:26215093). Interacts with CDC6 and ORC2 (PubMed:15684404). Interacts with HROB; the interaction recruits the MCM8-MCM9 complex to DNA damage sites (PubMed:31467087).TISSUE SPECIFICITY Highest levels in placenta, lung and pancreas. Low levels in skeletal muscle and kidney. Expressed in various tumors with highest levels in colon and lung cancers.INDUCTION By E2F1.SIMILARITY Belongs to the MCM family.CAUTION Was initially thought to play a role in DNA replication (PubMed:15684404). However, it was later shown that it is mainly involved in homologous recombination repair (PubMed:23401855). UniProt Q9UJA3 1 EQUAL 840 EQUAL Reactome Database ID Release 83 3006646 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=3006646 Reactome R-HSA-3006646 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-3006646.1 1 ORC2 Orc2 Origin recognition complex subunit 2 Reactome DB_ID: 68405 UniProt:Q13416 ORC2 ORC2 ORC2L FUNCTION Component of the origin recognition complex (ORC) that binds origins of replication. DNA-binding is ATP-dependent. The specific DNA sequences that define origins of replication have not been identified yet. ORC is required to assemble the pre-replication complex necessary to initiate DNA replication. Binds histone H3 and H4 trimethylation marks H3K9me3, H3K20me3 and H4K27me3. Stabilizes LRWD1, by protecting it from ubiquitin-mediated proteasomal degradation. Also stabilizes ORC3.SUBUNIT Component of ORC, a complex composed of at least 6 subunits: ORC1, ORC2, ORC3, ORC4, ORC5 and ORC6. ORC is regulated in a cell-cycle dependent manner. It is sequentially assembled at the exit from anaphase of mitosis and disassembled as cells enter S phase (PubMed:12909626, PubMed:17716973). Interacts with DBF4 (By similarity). Interacts with MCM10 (PubMed:11095689). Interacts with LRWD1 throughout the cell cycle; this interaction, wich occurs only with non-ubiquitinated form of LRWD1, prevents LRWD1 ubiquitination and hence stabilizes the protein (PubMed:22645314). Interacts with POLQ (PubMed:24989122).SIMILARITY Belongs to the ORC2 family. UniProt Q13416 1 EQUAL 577 EQUAL Reactome Database ID Release 83 68405 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68405 Reactome R-HSA-68405 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68405.2 1 Reactome Database ID Release 83 176970 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176970 Reactome R-HSA-176970 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176970.1 1 p-T195-ORC6 Reactome DB_ID: 9734715 UniProt:Q9Y5N6 ORC6 ORC6 ORC6L FUNCTION Component of the origin recognition complex (ORC) that binds origins of replication. DNA-binding is ATP-dependent. The specific DNA sequences that define origins of replication have not been identified yet. ORC is required to assemble the pre-replication complex necessary to initiate DNA replication. Does not bind histone H3 and H4 trimethylation marks H3K9me3, H3K27me3 and H4K20me3.SUBUNIT Component of ORC, a complex composed of at least 6 subunits: ORC1, ORC2, ORC3, ORC4, ORC5 and ORC6. ORC is regulated in a cell-cycle dependent manner. It is sequentially assembled at the exit from anaphase of mitosis and disassembled as cells enter S phase. Interacts with DBF4 (By similarity).SIMILARITY Belongs to the ORC6 family. UniProt Q9Y5N6 195 EQUAL O-phospho-L-threonine MOD MOD:00047 1 EQUAL 252 EQUAL Reactome Database ID Release 83 9734715 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=9734715 Reactome R-HSA-9734715 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-9734715.1 1 ORC4 Orc4 Origin recognition complex subunit 4 Reactome DB_ID: 68519 UniProt:O43929 ORC4 ORC4 ORC4L FUNCTION Component of the origin recognition complex (ORC) that binds origins of replication. DNA-binding is ATP-dependent. The specific DNA sequences that define origins of replication have not been identified yet. ORC is required to assemble the pre-replication complex necessary to initiate DNA replication. Binds histone H3 and H4 trimethylation marks H3K9me3, H3K27me3 and H4K20me3.SUBUNIT Component of ORC, a complex composed of at least 6 subunits: ORC1, ORC2, ORC3, ORC4, ORC5 and ORC6. ORC is regulated in a cell-cycle dependent manner. It is sequentially assembled at the exit from anaphase of mitosis and disassembled as cells enter S phase (PubMed:12909626, PubMed:17716973). Interacts with DBF4 (By similarity). Interacts with POLQ (PubMed:24989122).SIMILARITY Belongs to the ORC4 family. UniProt O43929 1 EQUAL 436 EQUAL Reactome Database ID Release 83 68519 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68519 Reactome R-HSA-68519 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68519.2 1 ORC1 Orc1 Origin recognition complex subunit 1 Replication control protein 1 Reactome DB_ID: 68522 UniProt:Q13415 ORC1 ORC1 ORC1L PARC1 FUNCTION Component of the origin recognition complex (ORC) that binds origins of replication. DNA-binding is ATP-dependent. The DNA sequences that define origins of replication have not been identified yet. ORC is required to assemble the pre-replication complex necessary to initiate DNA replication.SUBUNIT Component of ORC, a complex composed of at least 6 subunits: ORC1, ORC2, ORC3, ORC4, ORC5 and ORC6. ORC is regulated in a cell-cycle dependent manner. It is sequentially assembled at the exit from anaphase of mitosis and disassembled as cells enter S phase. Interacts with CDC6 and KAT7/HBO1. Interacts with LRWD1 predominantly during the G1 phase and with less affinity during mitosis, when phosphorylated.DEVELOPMENTAL STAGE Expression is cell-cycle regulated, it starts to accumulate in mid-G1 phase, reaches a peak at the G1/S boundary, and decreases to a basal level in S phase (at protein level).DOMAIN The BAH domain mediates binding to dimethylated histone H4 'Lys-20' (H4K20me2), which is enriched at replication origins.PTM Phosphorylated during mitosis.SIMILARITY Belongs to the ORC1 family. UniProt Q13415 1 EQUAL 861 EQUAL Reactome Database ID Release 83 68522 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68522 Reactome R-HSA-68522 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68522.2 1 ARS origin of replication origin autonomously replicating sequence Reactome DB_ID: 9749102 Reactome Database ID Release 83 9749102 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=9749102 Reactome R-HSA-9749102 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-9749102.1 ChEBI 61120 1 ORC3 Orc3 Origin recognition complex subunit 3 Origin recognition complex subunit Latheo Reactome DB_ID: 68513 UniProt:Q9UBD5 ORC3 ORC3 LATHEO ORC3L FUNCTION Component of the origin recognition complex (ORC) that binds origins of replication. DNA-binding is ATP-dependent. The specific DNA sequences that define origins of replication have not been identified yet. ORC is required to assemble the pre-replication complex necessary to initiate DNA replication. Binds histone H3 and H4 trimethylation marks H3K9me3, H3K27me3 and H4K20me3.SUBUNIT Component of ORC, a complex composed of at least 6 subunits: ORC1, ORC2, ORC3, ORC4, ORC5 and ORC6. ORC is regulated in a cell-cycle dependent manner. It is sequentially assembled at the exit from anaphase of mitosis and disassembled as cells enter S phase.PTM Multi-mono-ubiquitinated by OBI1; ubiquitination is important for efficient DNA replication origin site activation. Ubiquitination levels are low in mitotic and early G1-phAse cells and are induced in late G1-/early S-phase, peaking in S-phase and decrease toward the end of the cell cycle.SIMILARITY Belongs to the ORC3 family. UniProt Q9UBD5 1 EQUAL 711 EQUAL Reactome Database ID Release 83 68513 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68513 Reactome R-HSA-68513 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68513.2 1 ORC5 Orc5 Origin recognition complex subunit 5 Reactome DB_ID: 68516 UniProt:O43913 ORC5 ORC5 ORC5L FUNCTION Component of the origin recognition complex (ORC) that binds origins of replication. DNA-binding is ATP-dependent. The specific DNA sequences that define origins of replication have not been identified yet. ORC is required to assemble the pre-replication complex necessary to initiate DNA replication.SUBUNIT Component of ORC, a complex composed of at least 6 subunits: ORC1, ORC2, ORC3, ORC4, ORC5 and ORC6. ORC is regulated in a cell-cycle dependent manner. It is sequentially assembled at the exit from anaphase of mitosis and disassembled as cells enter S phase.TISSUE SPECIFICITY Abundant in spleen, ovary, prostate, testis, and colon mucosa.PTM Multi-mono-ubiquitinated by OBI1; ubiquitination is important for efficient DNA replication origin site activation. Ubiquitination levels are low in mitotic and early G1-phAse cells and are induced in late G1-/early S-phase, peaking in S-phase and decrease toward the end of the cell cycle.SIMILARITY Belongs to the ORC5 family. UniProt O43913 1 EQUAL 435 EQUAL Reactome Database ID Release 83 68516 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68516 Reactome R-HSA-68516 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68516.2 1 Reactome Database ID Release 83 68540 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68540 Reactome R-HSA-68540 3 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68540.3 1 CDC6 Reactome DB_ID: 68542 UniProt:Q99741 CDC6 CDC6 CDC18L FUNCTION Involved in the initiation of DNA replication. Also participates in checkpoint controls that ensure DNA replication is completed before mitosis is initiated.SUBUNIT Interacts with PCNA, ORC1, cyclin-CDK (PubMed:9566895). Interacts with HUWE1 (PubMed:17567951). Interacts with ANKRD17 (PubMed:23711367). Interacts with GRWD1; origin binding of GRWD1 is dependent on CDC6 (PubMed:25990725). Interacts with CDT1; are mutually dependent on one another for loading MCM complexes onto chromatin (PubMed:14672932). Interacts with TTC4 (PubMed:18320024). Interacts (via Cy motif) with CCNF; the interaction takes place during G2 and M phase (PubMed:26818844). Interacts with CDH1 (PubMed:26818844).PTM Ubiquitinated by the SCF(CCNF) E3 ubiquitin-protein ligase complex.SIMILARITY Belongs to the CDC6/cdc18 family. UniProt Q99741 1 EQUAL 560 EQUAL Reactome Database ID Release 83 68542 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68542 Reactome R-HSA-68542 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68542.2 1 Reactome Database ID Release 83 68543 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68543 Reactome R-HSA-68543 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68543.1 1 Reactome Database ID Release 83 156562 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=156562 Reactome R-HSA-156562 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-156562.1 1 Reactome Database ID Release 83 156564 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=156564 Reactome R-HSA-156564 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-156564.2 1 CDK Reactome DB_ID: 68380 cyclin Reactome DB_ID: 68379 Reactome Database ID Release 83 68379 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68379 Reactome R-HSA-68379 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68379.2 ChEBI 36080 1 CDK2 Cdk2 Cell division protein kinase 2 (EC 2.7.1.-)(p33 protein kinase)(CDK2) Cell division protein kinase 2 p33 protein kinase Reactome DB_ID: 68365 UniProt:P24941 CDK2 CDK2 CDKN2 FUNCTION Serine/threonine-protein kinase involved in the control of the cell cycle; essential for meiosis, but dispensable for mitosis. Phosphorylates CTNNB1, USP37, p53/TP53, NPM1, CDK7, RB1, BRCA2, MYC, NPAT, EZH2. Triggers duplication of centrosomes and DNA. Acts at the G1-S transition to promote the E2F transcriptional program and the initiation of DNA synthesis, and modulates G2 progression; controls the timing of entry into mitosis/meiosis by controlling the subsequent activation of cyclin B/CDK1 by phosphorylation, and coordinates the activation of cyclin B/CDK1 at the centrosome and in the nucleus. Crucial role in orchestrating a fine balance between cellular proliferation, cell death, and DNA repair in human embryonic stem cells (hESCs). Activity of CDK2 is maximal during S phase and G2; activated by interaction with cyclin E during the early stages of DNA synthesis to permit G1-S transition, and subsequently activated by cyclin A2 (cyclin A1 in germ cells) during the late stages of DNA replication to drive the transition from S phase to mitosis, the G2 phase. EZH2 phosphorylation promotes H3K27me3 maintenance and epigenetic gene silencing. Phosphorylates CABLES1 (By similarity). Cyclin E/CDK2 prevents oxidative stress-mediated Ras-induced senescence by phosphorylating MYC. Involved in G1-S phase DNA damage checkpoint that prevents cells with damaged DNA from initiating mitosis; regulates homologous recombination-dependent repair by phosphorylating BRCA2, this phosphorylation is low in S phase when recombination is active, but increases as cells progress towards mitosis. In response to DNA damage, double-strand break repair by homologous recombination a reduction of CDK2-mediated BRCA2 phosphorylation. Phosphorylation of RB1 disturbs its interaction with E2F1. NPM1 phosphorylation by cyclin E/CDK2 promotes its dissociates from unduplicated centrosomes, thus initiating centrosome duplication. Cyclin E/CDK2-mediated phosphorylation of NPAT at G1-S transition and until prophase stimulates the NPAT-mediated activation of histone gene transcription during S phase. Required for vitamin D-mediated growth inhibition by being itself inactivated. Involved in the nitric oxide- (NO) mediated signaling in a nitrosylation/activation-dependent manner. USP37 is activated by phosphorylation and thus triggers G1-S transition. CTNNB1 phosphorylation regulates insulin internalization. Phosphorylates FOXP3 and negatively regulates its transcriptional activity and protein stability (By similarity). Phosphorylates CDK2AP2 (PubMed:12944431). Phosphorylates ERCC6 which is essential for its chromatin remodeling activity at DNA double-strand breaks (PubMed:29203878).ACTIVITY REGULATION Phosphorylation at Thr-14 or Tyr-15 inactivates the enzyme, while phosphorylation at Thr-160 activates it (PubMed:1396589). Inhibited by 1,25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)), AG-024322, N-(4-Piperidinyl)-4-(2,6-dichlorobenzoylamino)-1H-pyrazole-3-carboxamide (AT7519), R547 (Ro-4584820), purine, pyrimidine and pyridine derivatives, 2-aminopyrimidines, paullones, thiazo derivatives, macrocyclic quinoxalin-2-one, pyrazolo[1,5-a]-1,3,5-triazine, pyrazolo[1,5-a]pyrimidine, 2-(1-ethyl-2-hydroxyethylamino)-6-benzylamino-9-isopropylpurine (roscovitine, seliciclib and CYC202), SNS-032 (BMS-387032), triazolo[1,5-a]pyrimidines, staurosporine and olomoucine. Stimulated by MYC. Inactivated by CDKN1A (p21).SUBUNIT Found in a complex with CABLES1, CCNA1 and CCNE1. Interacts with CABLES1 (By similarity). Interacts with UHRF2. Part of a complex consisting of UHRF2, CDK2 and CCNE1. Interacts with the Speedy/Ringo proteins SPDYA and SPDYC (PubMed:15611625). Interaction with SPDYA promotes kinase activation via a conformation change that alleviates obstruction of the substrate-binding cleft by the T-loop (PubMed:28666995). Found in a complex with both SPDYA and CDKN1B/KIP1 (PubMed:12972555, PubMed:28666995). Binds to RB1 and CDK7. Binding to CDKN1A (p21) leads to CDK2/cyclin E inactivation at the G1-S phase DNA damage checkpoint, thereby arresting cells at the G1-S transition during DNA repair. Associated with PTPN6 and beta-catenin/CTNNB1. Interacts with CACUL1. May interact with CEP63. Interacts with ANKRD17. Interacts with CEBPA (when phosphorylated) (PubMed:15107404). Forms a ternary complex with CCNA2 and CDKN1B; CDKN1B inhibits the kinase activity of CDK2 through conformational rearrangements (PubMed:8684460). Interacts with cyclins A, B1, B3, D, or E (PubMed:10499802, PubMed:10884347, PubMed:12185076, PubMed:23781148). Interacts with CDK2AP2 (PubMed:23781148).INDUCTION Induced transiently by TGFB1 at an early phase of TGFB1-mediated apoptosis.PTM Phosphorylated at Thr-160 by CDK7 in a CAK complex (PubMed:28666995). Phosphorylation at Thr-160 promotes kinase activity, whereas phosphorylation at Tyr-15 by WEE1 reduces slightly kinase activity. Phosphorylated on Thr-14 and Tyr-15 during S and G2 phases before being dephosphorylated by CDC25A.PTM Nitrosylated after treatment with nitric oxide (DETA-NO).SIMILARITY Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. CDC2/CDKX subfamily. UniProt P24941 1 EQUAL 298 EQUAL Reactome Database ID Release 83 68365 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68365 Reactome R-HSA-68365 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68365.2 1 Reactome Database ID Release 83 68380 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68380 Reactome R-HSA-68380 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68380.1 1 DDK Reactome DB_ID: 68388 DBF4 Dbf4 Reactome DB_ID: 68387 UniProt:Q9UBU7 DBF4 DBF4 ASK DBF4A ZDBF1 FUNCTION Regulatory subunit for CDC7 which activates its kinase activity thereby playing a central role in DNA replication and cell proliferation. Required for progression of S phase. The complex CDC7-DBF4A selectively phosphorylates MCM2 subunit at 'Ser-40' and 'Ser-53' and then is involved in regulating the initiation of DNA replication during cell cycle.SUBUNIT Forms a complex with CDC7. Note that CDC7 forms distinct complex either with DBF4A or DBF4B. Such complexes are stable upon replication stress. Interacts with MEN1, MCM2, ORC2, ORC4 and ORC6. Interacts (via IBM motifs) with PSIP1 (via IBD domain); phosphorylation increases its affinity for PSIP1 (PubMed:29997176).TISSUE SPECIFICITY Highly expressed in testis and thymus. Expressed also in most cancer cells lines.INDUCTION Induced in G1 phase at low level, increased during G1-S phase and remain high during S and G2-M phase.PTM Phosphorylation increases its interaction with PSIP1. UniProt Q9UBU7 1 EQUAL 674 EQUAL Reactome Database ID Release 83 68387 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68387 Reactome R-HSA-68387 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68387.2 1 CDC7 Cdc7 Cell division protein kinase 7 Cell division cycle 7-related protein kinase (EC 2.7.1.-) (CDC7- related kinase) (HsCdc7) (huCdc7) Cell division cycle 7-related protein kinase CDC7- related kinase HsCdc7 huCdc7 Reactome DB_ID: 51781 UniProt:O00311 CDC7 CDC7 CDC7L1 FUNCTION Kinase involved in initiation of DNA replication. Phosphorylates critical substrates that regulate the G1/S phase transition and initiation of DNA replication, such as MCM proteins and CLASPIN.SUBUNIT Forms a complex with either DBF4/DBF4A or DBF4B, leading to the activation of the kinase activity (PubMed:10373557, PubMed:12065429, PubMed:15668232, PubMed:17062569). Interacts with CLASPIN (via the acidic patch); the interaction is required for phosphorylation of MCM proteins and CLASPIN (PubMed:27401717).SIMILARITY Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. CDC7 subfamily. UniProt O00311 1 EQUAL 574 EQUAL Reactome Database ID Release 83 51781 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=51781 Reactome R-HSA-51781 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-51781.1 1 Reactome Database ID Release 83 68388 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68388 Reactome R-HSA-68388 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68388.1 1 Reactome Database ID Release 83 68561 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68561 Reactome R-HSA-68561 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68561.2 1 Reactome Database ID Release 83 68564 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=68564 Reactome R-HSA-68564 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-68564.2 claspin bound to DNA replication fork Cdc45:CDK:DDK:Mcm10:claspin:pre-replicative complex Reactome DB_ID: 176229 1 1 Reactome Database ID Release 83 176229 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176229 Reactome R-HSA-176229 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176229.1 Reactome Database ID Release 83 176318 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176318 Reactome R-HSA-176318 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176318.2 15226314 Pubmed 2004 Human claspin is a ring-shaped DNA-binding protein with high affinity to branched DNA structures Sar, F Lindsey-Boltz, LA Subramanian, D Croteau, DL Hutsell, SQ Griffith, JD Sancar, A J Biol Chem 279:39289-95 12620222 Pubmed 2003 Claspin, a Chk1-regulatory protein, monitors DNA replication on chromatin independently of RPA, ATR, and Rad17 Lee, J Kumagai, A Dunphy, WG Mol Cell 11:329-40 16148040 Pubmed 2005 Roles of replication fork-interacting and Chk1-activating domains from Claspin in a DNA replication checkpoint response Lee, J Gold, DA Shevchenko, Anna Shevchenko, Andrej Dunphy, WG Mol Biol Cell 16:5269-82 15279790 Pubmed 2004 Claspin, a regulator of Chk1 in DNA replication stress pathway Chini, CC Chen, J DNA Repair (Amst) 3:1033-7 11090622 Pubmed 2000 Claspin, a novel protein required for the activation of Chk1 during a DNA replication checkpoint response in Xenopus egg extracts Kumagai, A Dunphy, WG Mol Cell 6:839-49 12545175 Pubmed 2003 Repeated phosphopeptide motifs in Claspin mediate the regulated binding of Chk1 Kumagai, A Dunphy, WG Nat Cell Biol 5:161-5 LEFT-TO-RIGHT 2.7.11.1 Activation of claspin Claspin is a replication fork-associated protein important for Chk1 activation. Claspin loads onto the fork during replication origin firing and travels with the fork during DNA synthesis. Upon fork uncoupling and ATR-ATRIP binding to persistent ssDNA, the activated ATR kinase phosphorylates claspin at two primary sites. Modification increases the affinity of claspin for Chk1. Studies of human or Xenopus claspin indicate that phosphorylation of both sites is essential for significant claspin-Chk1 association. Following claspin modification by ATR, Chk1 can be transiently recruited to the stalled replication fork for subsequent phosphorylation and activation by ATR. Activation of Chk1 allows modification of additional downstream targets, thus amplifying the checkpoint signal. While much of the mechanistic information concerning claspin action has been obtained using Xenopus laevis egg extracts and Xenopus claspin, factors with similar activity have been found in various eukaryotic species including S. cerevisiae (MRC1), S. pombe (mrc1), and humans.<p>Activated ATR phosphorylates human claspin on two sites, threonine 916 and serine 945. Authored: Borowiec, JA, 2006-02-25 17:40:15 Edited: D'Eustachio, P, 2006-02-25 17:41:28 ATP Adenosine 5'-triphosphate ATP(4-) Reactome DB_ID: 29358 ATP(4-) [ChEBI:30616] ATP(4-) ATP atp Adenosine 5'-triphosphate ChEBI CHEBI:30616 Reactome Database ID Release 83 29358 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=29358 Reactome R-ALL-29358 3 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-ALL-29358.3 COMPOUND C00002 2 ADP Adenosine 5'-diphosphate ADP(3-) Reactome DB_ID: 113582 ADP(3-) [ChEBI:456216] ADP(3-) ADP 5&apos;-O-[(phosphonatooxy)phosphinato]adenosine ADP trianion ChEBI CHEBI:456216 Reactome Database ID Release 83 113582 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=113582 Reactome R-ALL-113582 3 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-ALL-113582.3 COMPOUND C00008 2 Activated claspin bound to DNA replication fork Cdc45:CDK:DDK:Mcm10:Activated claspin:pre-replicative complex Reactome DB_ID: 176182 1 p-T916,S945-CLSPN p-S945,T916-CLSPN Activated claspin Reactome DB_ID: 176296 945 EQUAL O-phospho-L-serine MOD MOD:00046 916 EQUAL 1 EQUAL 1339 EQUAL Reactome Database ID Release 83 176296 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176296 Reactome R-HSA-176296 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176296.1 1 Reactome Database ID Release 83 176182 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176182 Reactome R-HSA-176182 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176182.1 ACTIVATION activeUnit: #Protein4 GENE ONTOLOGY GO:0004674 Reactome Database ID Release 83 176203 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176203 Reactome Database ID Release 83 176298 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176298 Reactome R-HSA-176298 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176298.2 15707391 Pubmed 2005 DNA-dependent phosphorylation of Chk1 and Claspin in a human cell-free system Clarke, CA Clarke, PR Biochem J 388:705-12 LEFT-TO-RIGHT 2.7.11.1 Recruitment and activation of Chk1 Chk1 is a checkpoint kinase activated during genotoxic stress. Like ATR, Chk1 is essential for viability in mammals. Targeted gene disruption in mice shows that loss of Chk1 causes peri-implantation embryonic lethality. Even though ATR-ATRIP not bound to ssDNA can phosphorylate Chk1, Chk1 activation is greatly enhanced when recruited to stalled replication forks by physical interaction with a modified form of claspin and the Rad9-Hus1-Rad1 sliding clamp. Activation of Chk1 occurs following phosphorylation of two sites (serine 317 and serine 345). Mutational analysis indicates that modification of both sites is essential for maximal kinase activity, while phosphorylation of only a single site causes only weak activation of Chk1. Following phosphorylation, Chk1 can diffuse away from the complex to further amplify the checkpoint signal. ATR appears to be the primary kinase activating Chk1 as conditions that activate ATR (ultraviolet irradiation or treatment with hydroxyurea) also activate Chk1. Stresses that activate ATM, e.g., ionizing irradiation, do not cause significant Chk1 activation. While the ATR and ATM pathways are distinct, there is interplay between the two. For example, double-strand DNA breaks can be processed in an ATM-dependent manner to generate structures that can cause ATR and hence Chk1 activation. The ATR and ATM pathways also have mechanistic similarities. Analogous to the Chk1 kinase existing downstream of ATR, the Chk2 checkpoint kinase is modified and activated by ATM. Although having distinct structures, Chk1 and Chk2 also have overlapping targets with some substrate sites phosphorylatable by both kinases (e.g., serine 20 of p53). Authored: Borowiec, JA, 2006-02-25 17:40:15 Edited: D'Eustachio, P, 2006-02-25 17:41:28 Chk1 CHEK1 Serine/threonine-protein kinase Chk1 (EC 2.7.1.-) Serine/threonine-protein kinase Chk1 Reactome DB_ID: 113826 UniProt:O14757 CHEK1 CHEK1 CHK1 FUNCTION Serine/threonine-protein kinase which is required for checkpoint-mediated cell cycle arrest and activation of DNA repair in response to the presence of DNA damage or unreplicated DNA (PubMed:11535615, PubMed:12446774, PubMed:12399544, PubMed:14559997, PubMed:14988723, PubMed:15311285, PubMed:15665856, PubMed:15650047, PubMed:32357935). May also negatively regulate cell cycle progression during unperturbed cell cycles (PubMed:11535615, PubMed:12446774, PubMed:12399544, PubMed:14559997, PubMed:14988723, PubMed:15311285, PubMed:15665856, PubMed:15650047). This regulation is achieved by a number of mechanisms that together help to preserve the integrity of the genome (PubMed:11535615, PubMed:12446774, PubMed:12399544, PubMed:14559997, PubMed:14988723, PubMed:15311285, PubMed:15665856, PubMed:15650047). Recognizes the substrate consensus sequence [R-X-X-S/T] (PubMed:11535615, PubMed:12446774, PubMed:12399544, PubMed:14559997, PubMed:14988723, PubMed:15311285, PubMed:15665856, PubMed:15650047). Binds to and phosphorylates CDC25A, CDC25B and CDC25C (PubMed:9278511, PubMed:12676583, PubMed:14681206, PubMed:12676925, PubMed:12759351, PubMed:19734889, PubMed:14559997). Phosphorylation of CDC25A at 'Ser-178' and 'Thr-507' and phosphorylation of CDC25C at 'Ser-216' creates binding sites for 14-3-3 proteins which inhibit CDC25A and CDC25C (PubMed:9278511). Phosphorylation of CDC25A at 'Ser-76', 'Ser-124', 'Ser-178', 'Ser-279' and 'Ser-293' promotes proteolysis of CDC25A (PubMed:9278511, PubMed:12676583, PubMed:14681206, PubMed:12676925, PubMed:12759351, PubMed:19734889). Phosphorylation of CDC25A at 'Ser-76' primes the protein for subsequent phosphorylation at 'Ser-79', 'Ser-82' and 'Ser-88' by NEK11, which is required for polyubiquitination and degradation of CDCD25A (PubMed:9278511, PubMed:19734889, PubMed:20090422). Inhibition of CDC25 leads to increased inhibitory tyrosine phosphorylation of CDK-cyclin complexes and blocks cell cycle progression (PubMed:9278511). Also phosphorylates NEK6 (PubMed:18728393). Binds to and phosphorylates RAD51 at 'Thr-309', which promotes the release of RAD51 from BRCA2 and enhances the association of RAD51 with chromatin, thereby promoting DNA repair by homologous recombination (PubMed:15665856). Phosphorylates multiple sites within the C-terminus of TP53, which promotes activation of TP53 by acetylation and promotes cell cycle arrest and suppression of cellular proliferation (PubMed:10673501, PubMed:15659650, PubMed:16511572). Also promotes repair of DNA cross-links through phosphorylation of FANCE (PubMed:17296736). Binds to and phosphorylates TLK1 at 'Ser-743', which prevents the TLK1-dependent phosphorylation of the chromatin assembly factor ASF1A (PubMed:12660173, PubMed:12955071). This may enhance chromatin assembly both in the presence or absence of DNA damage (PubMed:12660173, PubMed:12955071). May also play a role in replication fork maintenance through regulation of PCNA (PubMed:18451105). May regulate the transcription of genes that regulate cell-cycle progression through the phosphorylation of histones (By similarity). Phosphorylates histone H3.1 (to form H3T11ph), which leads to epigenetic inhibition of a subset of genes (By similarity). May also phosphorylate RB1 to promote its interaction with the E2F family of transcription factors and subsequent cell cycle arrest (PubMed:17380128). Phosphorylates SPRTN, promoting SPRTN recruitment to chromatin (PubMed:31316063). Reduces replication stress and activates the G2/M checkpoint, by phosphorylating and inactivating PABIR1/FAM122A and promoting the serine/threonine-protein phosphatase 2A-mediated dephosphorylation and stabilization of WEE1 levels and activity (PubMed:33108758).ACTIVITY REGULATION Activated through phosphorylation predominantly by ATR but also by ATM in response to DNA damage or inhibition of DNA replication (PubMed:11390642, PubMed:12588868, PubMed:12676583, PubMed:12676962, PubMed:15665856, PubMed:19716789). Activation is modulated by several mediators including CLSPN, BRCA1 and FEM1B (PubMed:11836499, PubMed:12766152, PubMed:16963448, PubMed:19330022). Proteolytic cleavage at the C-terminus by SPRTN during normal DNA replication activates the protein kinase activity (PubMed:31316063).SUBUNIT Interacts (phosphorylated by ATR) with RAD51 (PubMed:15665856). Interacts with and phosphorylates CLSPN, an adapter protein that regulates the ATR-dependent phosphorylation of CHEK1 (PubMed:16963448). Interacts with BRCA1 (PubMed:11836499). Interacts with and phosphorylates CDC25A, CDC25B and CDC25C (PubMed:9278511). Interacts with FBXO6, which regulates CHEK1 (PubMed:19716789). Interacts with PPM1D, which regulates CHEK1 through dephosphorylation (PubMed:15870257). Interacts with TIMELESS; DNA damage-dependent (PubMed:15798197). Interacts with FEM1B; activates CHEK1 in response to stress (PubMed:19330022). Interacts with TLK1 (PubMed:12660173). Interacts with XPO1 and YWHAZ (PubMed:12676962). Interacts with CDK5RAP3; antagonizes CHEK1 (PubMed:19223857).TISSUE SPECIFICITY Expressed ubiquitously with the most abundant expression in thymus, testis, small intestine and colon.DOMAIN The autoinhibitory region (AIR) inhibits the activity of the kinase domain.PTM Phosphorylated by ATR in a RAD17-dependent manner in response to ultraviolet irradiation and inhibition of DNA replication. Phosphorylated by ATM in response to ionizing irradiation. ATM and ATR can both phosphorylate Ser-317 and Ser-345 and this results in enhanced kinase activity. Phosphorylation at Ser-345 induces a change in the conformation of the protein, activates the kinase activity and is a prerequisite for interaction with FBXO6 and subsequent ubiquitination at Lys-436. Phosphorylation at Ser-345 also increases binding to 14-3-3 proteins and promotes nuclear retention. Conversely, dephosphorylation at Ser-345 by PPM1D may contribute to exit from checkpoint mediated cell cycle arrest. Phosphorylation at Ser-280 by AKT1/PKB, may promote mono and/or diubiquitination. Also phosphorylated at undefined residues during mitotic arrest, resulting in decreased activity.PTM Ubiquitinated. Mono or diubiquitination promotes nuclear exclusion (By similarity). The activated form (phosphorylated on Ser-345) is polyubiquitinated at Lys-436 by some SCF-type E3 ubiquitin ligase complex containing FBXO6 promoting its degradation. Ubiquitination and degradation are required to terminate the checkpoint and ensure that activated CHEK1 does not accumulate as cells progress through S phase, when replication forks encounter transient impediments during normal DNA replication. 'Lys-63'-mediated ubiquitination by TRAF4 at Lys-132 activates cell cycle arrest and activation of DNA repair (PubMed:32357935).PTM Proteolytically cleaved at the C-terminus by SPRTN during normal DNA replication, thereby promoting CHEK1 removal from chromatin and activating the protein kinase activity.SIMILARITY Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. NIM1 subfamily. UniProt O14757 1 EQUAL 476 EQUAL Reactome Database ID Release 83 113826 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=113826 Reactome R-HSA-113826 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-113826.1 phospho-Chk1 p-S317,S345-CHEK1 Serine/threonine-protein kinase Chk1 (EC 2.7.1.-) phosphorylated Serine/threonine-protein kinase Chk1 Reactome DB_ID: 113838 317 EQUAL 345 EQUAL 1 EQUAL 476 EQUAL Reactome Database ID Release 83 113838 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=113838 Reactome R-HSA-113838 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-113838.1 ACTIVATION activeUnit: #Protein4 Reactome Database ID Release 83 176116 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176116 Reactome R-HSA-176116 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176116.2 11390642 Pubmed 2001 ATR-mediated checkpoint pathways regulate phosphorylation and activation of human Chk1 Zhao, H Piwnica-Worms, H Mol Cell Biol 21:4129-39 15190204 Pubmed 2004 ATR, Claspin and the Rad9-Rad1-Hus1 complex regulate Chk1 and Cdc25A in the absence of DNA damage Sorensen, CS Syljuasen, RG Lukas, J Bartek, J Cell Cycle 3:941-5 15279789 Pubmed 2004 Chk1 in the DNA damage response: conserved roles from yeasts to mammals Chen, Y Sanchez, Y DNA Repair (Amst) 3:1025-32 16360315 Pubmed 2006 Rapid PIKK-Dependent Release of Chk1 from Chromatin Promotes the DNA-Damage Checkpoint Response Smits, VA Reaper, PM Jackson, SP Curr Biol 16:150-9 15272308 Pubmed 2004 Chk1, but not Chk2, inhibits Cdc25 phosphatases by a novel common mechanism Uto, K Inoue, D Shimuta, K Nakajo, N Sagata, N EMBO J 23:3386-96 16431910 Pubmed 2006 Rapid activation of ATR by ionizing radiation requires ATM and Mre11 Myers, JS Cortez, D J Biol Chem 10859164 Pubmed 2000 Chk1 is an essential kinase that is regulated by Atr and required for the G(2)/M DNA damage checkpoint. Liu, Q Guntuku, S Cui, XS Matsuoka, S Cortez, D Tamai, K Luo, G Carattini-Rivera, S DeMayo, F Bradley, A Donehower, LA Elledge, SJ Genes Dev 14:1448-59 12781359 Pubmed 2003 Chk1 and Chk2 kinases in checkpoint control and cancer Bartek, J Lukas, J Cancer Cell 3:421-9 12766152 Pubmed 2003 Human claspin is required for replication checkpoint control Chini, CC Chen, J J Biol Chem 278:30057-62 10859163 Pubmed 2000 Aberrant cell cycle checkpoint function and early embryonic death in Chk1(-/-) mice Takai, H Tominaga, K Motoyama, N Minamishima, YA Nagahama, H Tsukiyama, T Ikeda, K Nakayama, Keiko Nakanishi, M Nakayama, Ken-ichi Genes Dev 14:1439-47 LEFT-TO-RIGHT 2.7.11.1 Phosphorylation of Cdc25A at Ser-123 by Chk1 Detection of DNA damage caused by ionizing radiation results in the phosphorylation of Cdc25A at Ser-123 by Chk1, inhibiting Cdc25A. CDC25A Cdc25A M-phase inducer phosphatase 1 (EC 3.1.3.48) (Dual specificity phosphatase Cdc25A) M-phase inducer phosphatase 1 Dual specificity phosphatase Cdc25A Reactome DB_ID: 143487 UniProt:P30304 CDC25A CDC25A FUNCTION Tyrosine protein phosphatase which functions as a dosage-dependent inducer of mitotic progression. Directly dephosphorylates CDK1 and stimulates its kinase activity. Also dephosphorylates CDK2 in complex with cyclin E, in vitro.ACTIVITY REGULATION Stimulated by B-type cyclins. Stimulated by PIM1-mediated phosphorylation.SUBUNIT Interacts with CCNB1/cyclin B1. Interacts with YWHAE/14-3-3 epsilon when phosphorylated. Interacts with CUL1 specifically when CUL1 is neddylated and active. Interacts with BTRC/BTRCP1 and FBXW11/BTRCP2. Interactions with CUL1, BTRC and FBXW11 are enhanced upon DNA damage. Interacts with PIM1. Interacts with CHEK2; mediates CDC25A phosphorylation and degradation in response to infrared-induced DNA damages. Interacts with HSP90AB1; prevents heat shock-mediated CDC25A degradation and contributes to cell cycle progression (PubMed:22843495).DOMAIN The phosphodegron motif mediates interaction with specific F-box proteins when phosphorylated. Putative phosphorylation sites at Ser-79 and Ser-82 appear to be essential for this interaction.PTM Phosphorylated by CHEK1 on Ser-76, Ser-124, Ser-178, Ser-279, Ser-293 and Thr-507 during checkpoint mediated cell cycle arrest. Also phosphorylated by CHEK2 on Ser-124, Ser-279, and Ser-293 during checkpoint mediated cell cycle arrest. Phosphorylation on Ser-178 and Thr-507 creates binding sites for YWHAE/14-3-3 epsilon which inhibits CDC25A. Phosphorylation on Ser-76, Ser-124, Ser-178, Ser-279 and Ser-293 may also promote ubiquitin-dependent proteolysis of CDC25A by the SCF complex. Phosphorylation of CDC25A at Ser-76 by CHEK1 primes it for subsequent phosphorylation at Ser-79, Ser-82 and Ser-88 by NEK11. Phosphorylation by NEK11 is required for BTRC-mediated polyubiquitination and degradation. Phosphorylation by PIM1 leads to an increase in phosphatase activity. Phosphorylated by PLK3 following DNA damage, leading to promote its ubiquitination and degradation.PTM Ubiquitinated by the anaphase promoting complex/cyclosome (APC/C) ubiquitin ligase complex that contains FZR1/CDH1 during G1 phase leading to its degradation by the proteasome. Ubiquitinated by a SCF complex containing BTRC and FBXW11 during S phase leading to its degradation by the proteasome. Deubiquitination by USP17L2/DUB3 leads to its stabilization.SIMILARITY Belongs to the MPI phosphatase family. UniProt P30304 1 EQUAL 524 EQUAL Reactome Database ID Release 83 143487 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=143487 Reactome R-HSA-143487 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-143487.1 p-S123-CDC25A phospho-Cdc25A Reactome DB_ID: 143488 123 EQUAL 1 EQUAL 524 EQUAL Reactome Database ID Release 83 143488 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=143488 Reactome R-HSA-143488 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-143488.1 ACTIVATION Reactome Database ID Release 83 143490 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=143490 Reactome Database ID Release 83 69604 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=69604 Reactome R-HSA-69604 3 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-69604.3 12399544 Pubmed 2002 Disruption of the checkpoint kinase 1/cell division cycle 25A pathway abrogates ionizing radiation-induced S and G2 checkpoints. Zhao, H Watkins, JL Piwnica-Worms, H Proc Natl Acad Sci U S A 99:14795-800 LEFT-TO-RIGHT 2.7.11.1 Phosphorylation of Cdc25C at Ser 216 by Chk1 Phosphorylation of Cdc25C at Ser 216 results in both the inhibition of Cdc25C phosphatase activity and the creation of a 14-3-3 docking site (Peng et al. 1997). Authored: Matthews, L, 2003-08-05 01:10:00 Edited: Matthews, L, 2006-07-10 19:19:59 CDC25C Cdc25C M-phase inducer phosphatase 3 (EC 3.1.3.48) (Dual specificity phosphatase Cdc25C) M-phase inducer phosphatase 3 Dual specificity phosphatase Cdc25C Reactome DB_ID: 69741 UniProt:P30307 CDC25C CDC25C FUNCTION Functions as a dosage-dependent inducer in mitotic control. Tyrosine protein phosphatase required for progression of the cell cycle. When phosphorylated, highly effective in activating G2 cells into prophase. Directly dephosphorylates CDK1 and activates its kinase activity.SUBUNIT Interacts with MAPK14 and 14-3-3 proteins (PubMed:11333986). When phosphorylated on Ser-129 and/or Thr-130, interacts with PLK1 (PubMed:12595692). Interacts with MARK3/C-TAK1 (PubMed:12941695).SUBUNIT (Microbial infection) Interacts with HIV-1 Vpr; this interaction inactivates CDC25C phosphatase activity.DEVELOPMENTAL STAGE Expressed predominantly in G2 phase.PTM Phosphorylated by CHEK1 and MAPK14 at Ser-216. This phosphorylation creates a binding site for 14-3-3 protein and inhibits the phosphatase. Phosphorylated by PLK4. Phosphorylated by PLK1, leading to activate the phosphatase activity. Phosphorylation by PLK3 at Ser-191 promotes nuclear translocation. Ser-198 is a minor phosphorylation site. Was initially reported to be phosphorylated by PLK3 at Ser-216 (PubMed:10557092). However, such phosphorylation by PLK3 was not confirmed by other groups. Phosphorylation at Thr-48, Thr-67, Ser-122, Thr-130, Ser-168 and Ser-214 occurs at G2 and G2-M transition and is probably catalyzed by CDK1. Ser-168 phosphorylation levels are lower than those at the other 5 CDK1 sites. Phosphorylation by CDK1 leads to increased activity.SIMILARITY Belongs to the MPI phosphatase family. UniProt P30307 1 EQUAL 473 EQUAL Reactome Database ID Release 83 69741 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=69741 Reactome R-HSA-69741 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-69741.1 p-S216-CDC25C phosph-Cdc25C (Ser 216) M-phase inducer phosphatase 3 Dual specificity phosphatase Cdc25C Reactome DB_ID: 156496 216 EQUAL 1 EQUAL 473 EQUAL Reactome Database ID Release 83 156496 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=156496 Reactome R-HSA-156496 1 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-156496.1 ACTIVATION Reactome Database ID Release 83 182636 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=182636 Reactome Database ID Release 83 75010 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=75010 Reactome R-HSA-75010 4 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-75010.4 9278512 Pubmed 1997 Mitotic and G2 checkpoint control: regulation of 14-3-3 protein binding by phosphorylation of Cdc25C on serine-216. Peng, CY Graves, PR Thoma, RS Wu, Z Shaw, AS Piwnica-Worms, H Science 277:1501-5 Reactome Database ID Release 83 176187 Database identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current&ID=176187 Reactome R-HSA-176187 2 Reactome stable identifier. Use this URL to connect to the web page of this instance in Reactome: http://www.reactome.org/cgi-bin/eventbrowser_st_id?ST_ID=R-HSA-176187.2 15530773 Pubmed 2004 The DNA damage response: sensing and signaling McGowan, CH Russell, P Curr Opin Cell Biol 16:629-33 16314342 Pubmed 2005 DNA damage checkpoints in mammals Niida, H Nakanishi, M Mutagenesis