BioPAX pathway converted from "AKT1 E17K mutant phosphorylates CHUK (IKKalpha)" in the Reactome database. LEFT-TO-RIGHT 2.7.11.1 AKT1 E17K mutant phosphorylates CHUK (IKKalpha) AKT1 E17K gain-of-function mutant is expected to phosphorylate CHUK (IKKalpha), like the wild-type AKT (Ozes et al. 1999), but this has not been experimentally tested. Authored: Orlic-Milacic, M, 2012-07-18 Reviewed: Thorpe, Lauren, 2012-08-13 Reviewed: Yuzugullu, Haluk, 2012-08-13 Reviewed: Zhao, Jean J, 2012-08-13 Edited: Matthews, L, 2012-08-03 CHUK IKKA IKK1 Inhibitor of nuclear factor kappa-B kinase alpha subunit Reactome DB_ID: 168104 cytosol GENE ONTOLOGY GO:0005829 UniProt:O15111 CHUK CHUK IKKA TCF16 FUNCTION Serine kinase that plays an essential role in the NF-kappa-B signaling pathway which is activated by multiple stimuli such as inflammatory cytokines, bacterial or viral products, DNA damages or other cellular stresses (PubMed:9244310, PubMed:9252186, PubMed:9346484, PubMed:18626576). Acts as part of the canonical IKK complex in the conventional pathway of NF-kappa-B activation and phosphorylates inhibitors of NF-kappa-B on serine residues (PubMed:9244310, PubMed:9252186, PubMed:9346484, PubMed:18626576). These modifications allow polyubiquitination of the inhibitors and subsequent degradation by the proteasome (PubMed:9244310, PubMed:9252186, PubMed:9346484, PubMed:18626576). In turn, free NF-kappa-B is translocated into the nucleus and activates the transcription of hundreds of genes involved in immune response, growth control, or protection against apoptosis (PubMed:9244310, PubMed:9252186, PubMed:9346484, PubMed:18626576). Negatively regulates the pathway by phosphorylating the scaffold protein TAXBP1 and thus promoting the assembly of the A20/TNFAIP3 ubiquitin-editing complex (composed of A20/TNFAIP3, TAX1BP1, and the E3 ligases ITCH and RNF11) (PubMed:21765415). Therefore, CHUK plays a key role in the negative feedback of NF-kappa-B canonical signaling to limit inflammatory gene activation. As part of the non-canonical pathway of NF-kappa-B activation, the MAP3K14-activated CHUK/IKKA homodimer phosphorylates NFKB2/p100 associated with RelB, inducing its proteolytic processing to NFKB2/p52 and the formation of NF-kappa-B RelB-p52 complexes (PubMed:20501937). In turn, these complexes regulate genes encoding molecules involved in B-cell survival and lymphoid organogenesis. Participates also in the negative feedback of the non-canonical NF-kappa-B signaling pathway by phosphorylating and destabilizing MAP3K14/NIK. Within the nucleus, phosphorylates CREBBP and consequently increases both its transcriptional and histone acetyltransferase activities (PubMed:17434128). Modulates chromatin accessibility at NF-kappa-B-responsive promoters by phosphorylating histones H3 at 'Ser-10' that are subsequently acetylated at 'Lys-14' by CREBBP (PubMed:12789342). Additionally, phosphorylates the CREBBP-interacting protein NCOA3. Also phosphorylates FOXO3 and may regulate this pro-apoptotic transcription factor (PubMed:15084260). Phosphorylates RIPK1 at 'Ser-25' which represses its kinase activity and consequently prevents TNF-mediated RIPK1-dependent cell death (By similarity). Phosphorylates AMBRA1 following mitophagy induction, promoting AMBRA1 interaction with ATG8 family proteins and its mitophagic activity (PubMed:30217973).ACTIVITY REGULATION Activated when phosphorylated and inactivated when dephosphorylated.SUBUNIT Component of the I-kappa-B-kinase (IKK) core complex consisting of CHUK, IKBKB and IKBKG; probably four alpha/CHUK-beta/IKBKB dimers are associated with four gamma/IKBKG subunits (PubMed:32935379). The IKK core complex seems to associate with regulatory or adapter proteins to form a IKK-signalosome holo-complex (PubMed:10195894, PubMed:12612076). The IKK complex associates with TERF2IP/RAP1, leading to promote IKK-mediated phosphorylation of RELA/p65 (By similarity). Part of a complex composed of NCOA2, NCOA3, CHUK/IKKA, IKBKB, IKBKG and CREBBP (PubMed:11971985). Part of a 70-90 kDa complex at least consisting of CHUK/IKKA, IKBKB, NFKBIA, RELA, ELP1 and MAP3K14 (PubMed:9751059). Directly interacts with TRPC4AP (By similarity). May interact with TRAF2 (PubMed:19150425). Interacts with NALP2 (PubMed:15456791). May interact with MAVS/IPS1 (PubMed:16177806). Interacts with ARRB1 and ARRB2 (PubMed:15173580). Interacts with NLRC5; prevents CHUK phosphorylation and kinase activity (PubMed:20434986). Interacts with PIAS1; this interaction induces PIAS1 phosphorylation (PubMed:17540171). Interacts with ZNF268 isoform 2; the interaction is further increased in a TNF-alpha-dependent manner (PubMed:23091055). Interacts with FOXO3 (PubMed:15084260). Interacts with IFIT5; the interaction synergizes the recruitment of IKK to MAP3K7 and enhances IKK phosphorylation (PubMed:26334375). Interacts with LRRC14 (PubMed:27426725). Interacts with SASH1 (PubMed:23776175). Directly interacts with DDX3X after the physiological activation of the TLR7 and TLR8 pathways; this interaction enhances CHUK autophosphorylation (PubMed:30341167).SUBUNIT (Microbial infection) Interacts with InlC of Listeria monocytogenes.TISSUE SPECIFICITY Widely expressed.DOMAIN The kinase domain is located in the N-terminal region. The leucine zipper is important to allow homo- and hetero-dimerization. At the C-terminal region is located the region responsible for the interaction with NEMO/IKBKG.PTM Phosphorylated by MAP3K14/NIK, AKT and to a lesser extent by MEKK1, and dephosphorylated by PP2A. Autophosphorylated.PTM (Microbial infection) Acetylation of Thr-179 by Yersinia YopJ prevents phosphorylation and activation, thus blocking the I-kappa-B signaling pathway.SIMILARITY Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. I-kappa-B kinase subfamily. Homo sapiens NCBI Taxonomy 9606 UniProt O15111 1 EQUAL 745 EQUAL Reactome Database ID Release 81 168104 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=168104 Reactome R-HSA-168104 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-168104.2 Reactome http://www.reactome.org ATP Adenosine 5'-triphosphate ATP(4-) Reactome DB_ID: 113592 ATP(4-) [ChEBI:30616] ATP(4-) ATP atp Adenosine 5'-triphosphate ChEBI CHEBI:30616 Reactome Database ID Release 81 113592 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=113592 Reactome R-ALL-113592 5 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-113592.5 COMPOUND C00002 additional information MI MI:0361 p-T23-CHUK p-T23-IKKA p-T23-IKK1 Phospho-IKK1 (T23) Reactome DB_ID: 198615 23 EQUAL O-phospho-L-threonine MOD MOD:00047 1 EQUAL 745 EQUAL Reactome Database ID Release 81 198615 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=198615 Reactome R-HSA-198615 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-198615.1 ADP Adenosine 5'-diphosphate ADP(3-) Reactome DB_ID: 29370 ADP(3-) [ChEBI:456216] ADP(3-) ADP 5'-O-[(phosphonatooxy)phosphinato]adenosine ADP trianion ChEBI CHEBI:456216 Reactome Database ID Release 81 29370 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=29370 Reactome R-ALL-29370 5 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-29370.5 COMPOUND C00008 ACTIVATION p-T308,S473-AKT1 E17K Reactome DB_ID: 2243935 UniProt:P31749 AKT1 AKT1 PKB RAC FUNCTION AKT1 is one of 3 closely related serine/threonine-protein kinases (AKT1, AKT2 and AKT3) called the AKT kinase, and which regulate many processes including metabolism, proliferation, cell survival, growth and angiogenesis (PubMed:15526160, PubMed:11882383, PubMed:21620960, PubMed:21432781). This is mediated through serine and/or threonine phosphorylation of a range of downstream substrates (PubMed:15526160, PubMed:11882383, PubMed:21620960, PubMed:21432781). Over 100 substrate candidates have been reported so far, but for most of them, no isoform specificity has been reported (PubMed:15526160, PubMed:11882383, PubMed:21620960, PubMed:21432781). AKT is responsible of the regulation of glucose uptake by mediating insulin-induced translocation of the SLC2A4/GLUT4 glucose transporter to the cell surface (By similarity). Phosphorylation of PTPN1 at 'Ser-50' negatively modulates its phosphatase activity preventing dephosphorylation of the insulin receptor and the attenuation of insulin signaling (By similarity). Phosphorylation of TBC1D4 triggers the binding of this effector to inhibitory 14-3-3 proteins, which is required for insulin-stimulated glucose transport (PubMed:11994271). AKT regulates also the storage of glucose in the form of glycogen by phosphorylating GSK3A at 'Ser-21' and GSK3B at 'Ser-9', resulting in inhibition of its kinase activity (By similarity). Phosphorylation of GSK3 isoforms by AKT is also thought to be one mechanism by which cell proliferation is driven (By similarity). AKT regulates also cell survival via the phosphorylation of MAP3K5 (apoptosis signal-related kinase) (PubMed:11154276). Phosphorylation of 'Ser-83' decreases MAP3K5 kinase activity stimulated by oxidative stress and thereby prevents apoptosis (PubMed:11154276). AKT mediates insulin-stimulated protein synthesis by phosphorylating TSC2 at 'Ser-939' and 'Thr-1462', thereby activating mTORC1 signaling and leading to both phosphorylation of 4E-BP1 and in activation of RPS6KB1 (PubMed:12150915). AKT is involved in the phosphorylation of members of the FOXO factors (Forkhead family of transcription factors), leading to binding of 14-3-3 proteins and cytoplasmic localization (PubMed:10358075). In particular, FOXO1 is phosphorylated at 'Thr-24', 'Ser-256' and 'Ser-319' (PubMed:10358075). FOXO3 and FOXO4 are phosphorylated on equivalent sites (PubMed:10358075). AKT has an important role in the regulation of NF-kappa-B-dependent gene transcription and positively regulates the activity of CREB1 (cyclic AMP (cAMP)-response element binding protein) (PubMed:9829964). The phosphorylation of CREB1 induces the binding of accessory proteins that are necessary for the transcription of pro-survival genes such as BCL2 and MCL1 (PubMed:9829964). AKT phosphorylates 'Ser-454' on ATP citrate lyase (ACLY), thereby potentially regulating ACLY activity and fatty acid synthesis (By similarity). Activates the 3B isoform of cyclic nucleotide phosphodiesterase (PDE3B) via phosphorylation of 'Ser-273', resulting in reduced cyclic AMP levels and inhibition of lipolysis (By similarity). Phosphorylates PIKFYVE on 'Ser-318', which results in increased PI(3)P-5 activity (By similarity). The Rho GTPase-activating protein DLC1 is another substrate and its phosphorylation is implicated in the regulation cell proliferation and cell growth. AKT plays a role as key modulator of the AKT-mTOR signaling pathway controlling the tempo of the process of newborn neurons integration during adult neurogenesis, including correct neuron positioning, dendritic development and synapse formation (By similarity). Signals downstream of phosphatidylinositol 3-kinase (PI(3)K) to mediate the effects of various growth factors such as platelet-derived growth factor (PDGF), epidermal growth factor (EGF), insulin and insulin-like growth factor I (IGF-I) (PubMed:12176338, PubMed:12964941). AKT mediates the antiapoptotic effects of IGF-I (By similarity). Essential for the SPATA13-mediated regulation of cell migration and adhesion assembly and disassembly (PubMed:19934221). May be involved in the regulation of the placental development (By similarity). Phosphorylates STK4/MST1 at 'Thr-120' and 'Thr-387' leading to inhibition of its: kinase activity, nuclear translocation, autophosphorylation and ability to phosphorylate FOXO3 (PubMed:17726016). Phosphorylates STK3/MST2 at 'Thr-117' and 'Thr-384' leading to inhibition of its: cleavage, kinase activity, autophosphorylation at Thr-180, binding to RASSF1 and nuclear translocation (PubMed:20086174, PubMed:20231902). Phosphorylates SRPK2 and enhances its kinase activity towards SRSF2 and ACIN1 and promotes its nuclear translocation (PubMed:19592491). Phosphorylates RAF1 at 'Ser-259' and negatively regulates its activity (PubMed:10576742). Phosphorylation of BAD stimulates its pro-apoptotic activity (PubMed:10926925). Phosphorylates KAT6A at 'Thr-369' and this phosphorylation inhibits the interaction of KAT6A with PML and negatively regulates its acetylation activity towards p53/TP53 (PubMed:23431171). Phosphorylates palladin (PALLD), modulating cytoskeletal organization and cell motility (PubMed:20471940). Phosphorylates prohibitin (PHB), playing an important role in cell metabolism and proliferation (PubMed:18507042). Phosphorylates CDKN1A, for which phosphorylation at 'Thr-145' induces its release from CDK2 and cytoplasmic relocalization (PubMed:16982699). These recent findings indicate that the AKT1 isoform has a more specific role in cell motility and proliferation (PubMed:16139227). Phosphorylates CLK2 thereby controlling cell survival to ionizing radiation (PubMed:20682768). Phosphorylates PCK1 at 'Ser-90', reducing the binding affinity of PCK1 to oxaloacetate and changing PCK1 into an atypical protein kinase activity using GTP as donor (PubMed:32322062). Also acts as an activator of TMEM175 potassium channel activity in response to growth factors: forms the lysoK(GF) complex together with TMEM175 and acts by promoting TMEM175 channel activation, independently of its protein kinase activity (PubMed:32228865).ACTIVITY REGULATION Three specific sites, one in the kinase domain (Thr-308) and the two other ones in the C-terminal regulatory region (Ser-473 and Tyr-474), need to be phosphorylated for its full activation. Inhibited by pyrrolopyrimidine inhibitors like aniline triazole and spiroindoline.SUBUNIT Interacts with BTBD10 (By similarity). Interacts with KCTD20 (By similarity). Interacts (via the C-terminus) with CCDC88A (via its C-terminus). Interacts with GRB10; the interaction leads to GRB10 phosphorylation thus promoting YWHAE-binding (By similarity). Interacts with AGAP2 (isoform 2/PIKE-A); the interaction occurs in the presence of guanine nucleotides. Interacts with AKTIP. Interacts (via PH domain) with MTCP1, TCL1A AND TCL1B. Interacts with CDKN1B; the interaction phosphorylates CDKN1B promoting 14-3-3 binding and cell-cycle progression. Interacts with MAP3K5 and TRAF6. Interacts with BAD, PPP2R5B, STK3 and STK4. Interacts (via PH domain) with SIRT1. Interacts with SRPK2 in a phosphorylation-dependent manner. Interacts with RAF1. Interacts with TRIM13; the interaction ubiquitinates AKT1 leading to its proteasomal degradation. Interacts with TNK2 and CLK2. Interacts (via the C-terminus) with THEM4 (via its C-terminus). Interacts with and phosphorylated by PDPK1. Interacts with PA2G4 (By similarity). Interacts with KIF14; the interaction is detected in the plasma membrane upon INS stimulation and promotes AKT1 phosphorylation (PubMed:24784001). Interacts with FAM83B; activates the PI3K/AKT signaling cascade (PubMed:23676467). Interacts with WDFY2 (via WD repeats 1-3) (PubMed:16792529). Forms a complex with WDFY2 and FOXO1 (By similarity). Interacts with FAM168A (PubMed:23251525). Interacts with SYAP1 (via phosphorylated form and BSD domain); this interaction is enhanced in a mTORC2-mediated manner in response to epidermal growth factor (EGF) stimulation and activates AKT1 (PubMed:23300339). Interacts with PKHM3 (By similarity). Interacts with FKBP5/FKBP51; promoting interaction between Akt/AKT1 and PHLPP1, thereby enhancing dephosphorylation and subsequent activation of Akt/AKT1 (PubMed:28147277). Interacts with TMEM175; leading to formation of the lysoK(GF) complex (PubMed:32228865). Acts as a negative regulator of the cGAS-STING pathway by mediating phosphorylation of CGAS during mitosis, leading to its inhibition (PubMed:26440888).TISSUE SPECIFICITY Expressed in prostate cancer and levels increase from the normal to the malignant state (at protein level). Expressed in all human cell types so far analyzed. The Tyr-176 phosphorylated form shows a significant increase in expression in breast cancers during the progressive stages i.e. normal to hyperplasia (ADH), ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC) and lymph node metastatic (LNMM) stages.DOMAIN Binding of the PH domain to phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) following phosphatidylinositol 3-kinase alpha (PIK3CA) activity results in its targeting to the plasma membrane. The PH domain mediates interaction with TNK2 and Tyr-176 is also essential for this interaction.DOMAIN The AGC-kinase C-terminal mediates interaction with THEM4.PTM O-GlcNAcylation at Thr-305 and Thr-312 inhibits activating phosphorylation at Thr-308 via disrupting the interaction between AKT1 and PDPK1. O-GlcNAcylation at Ser-473 also probably interferes with phosphorylation at this site.PTM Phosphorylation on Thr-308, Ser-473 and Tyr-474 is required for full activity (PubMed:12149249, PubMed:14761976, PubMed:15047712, PubMed:16266983, PubMed:17013611, PubMed:20978158, PubMed:9736715, PubMed:23799035, PubMed:8978681, PubMed:28147277). Activated TNK2 phosphorylates it on Tyr-176 resulting in its binding to the anionic plasma membrane phospholipid PA (PubMed:20333297). This phosphorylated form localizes to the cell membrane, where it is targeted by PDPK1 and PDPK2 for further phosphorylations on Thr-308 and Ser-473 leading to its activation (PubMed:9512493). Ser-473 phosphorylation by mTORC2 favors Thr-308 phosphorylation by PDPK1 (PubMed:21464307, PubMed:8978681). Phosphorylated at Thr-308 and Ser-473 by IKBKE and TBK1 (PubMed:15718470, PubMed:18456494, PubMed:20481595, PubMed:8978681). Ser-473 phosphorylation is enhanced by interaction with AGAP2 isoform 2 (PIKE-A) (PubMed:14761976). Ser-473 phosphorylation is enhanced in focal cortical dysplasias with Taylor-type balloon cells (PubMed:17013611). Ser-473 phosphorylation is enhanced by signaling through activated FLT3 (By similarity). Ser-473 is dephosphorylated by PHLPP (PubMed:28147277). Dephosphorylated at Thr-308 and Ser-473 by PP2A phosphatase (PubMed:21329884). The phosphorylated form of PPP2R5B is required for bridging AKT1 with PP2A phosphatase (PubMed:21329884). Ser-473 is dephosphorylated by CPPED1, leading to termination of signaling (PubMed:9512493).PTM Ubiquitinated; undergoes both 'Lys-48'- and 'Lys-63'-linked polyubiquitination. TRAF6-induced 'Lys-63'-linked AKT1 ubiquitination is critical for phosphorylation and activation (PubMed:19713527). When ubiquitinated, it translocates to the plasma membrane, where it becomes phosphorylated (PubMed:20059950). When fully phosphorylated and translocated into the nucleus, undergoes 'Lys-48'-polyubiquitination catalyzed by TTC3, leading to its degradation by the proteasome (PubMed:20059950). Also ubiquitinated by TRIM13 leading to its proteasomal degradation (PubMed:21333377). Phosphorylated, undergoes 'Lys-48'-linked polyubiquitination preferentially at Lys-284 catalyzed by MUL1, leading to its proteasomal degradation (PubMed:22410793). Ubiquitinated via 'Lys-48'-linked polyubiquitination by ZNRF1, leading to its degradation by the proteasome (By similarity).PTM Acetylated on Lys-14 and Lys-20 by the histone acetyltransferases EP300 and KAT2B. Acetylation results in reduced phosphorylation and inhibition of activity. Deacetylated at Lys-14 and Lys-20 by SIRT1. SIRT1-mediated deacetylation relieves the inhibition.PTM Cleavage by caspase-3/CASP3 (By similarity). Cleaved at the caspase-3 consensus site Asp-462 during apoptosis, resulting in down-regulation of the AKT signaling pathway and decreased cell survival (PubMed:23152800).DISEASE Genetic variations in AKT1 may play a role in susceptibility to ovarian cancer.MISCELLANEOUS (2S)-2-(4-chlorobenzyl)-3-oxo-3-[4-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)piperazin-1-yl]propan-1-amine corresponds to compound 44.MISCELLANEOUS 5-(5-chloro-1H-pyrrolo[2,3-d]pyrimidin-4-yl)-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine corresponds to compound 8b.SIMILARITY Belongs to the protein kinase superfamily. AGC Ser/Thr protein kinase family. RAC subfamily.CAUTION PUBMED:19940129 has been retracted because the same data were used to represent different experimental conditions.CAUTION In light of strong homologies in the primary amino acid sequence, the 3 AKT kinases were long surmised to play redundant and overlapping roles. More recent studies has brought into question the redundancy within AKT kinase isoforms and instead pointed to isoform specific functions in different cellular events and diseases. AKT1 is more specifically involved in cellular survival pathways, by inhibiting apoptotic processes; whereas AKT2 is more specific for the insulin receptor signaling pathway. Moreover, while AKT1 and AKT2 are often implicated in many aspects of cellular transformation, the 2 isoforms act in a complementary opposing manner. The role of AKT3 is less clear, though it appears to be predominantly expressed in brain. UniProt P31749 17 EQUAL L-glutamic acid removal MOD MOD:01636 473 EQUAL O-phospho-L-serine MOD MOD:00046 308 EQUAL 1 EQUAL 480 EQUAL Reactome Database ID Release 81 2243935 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=2243935 Reactome R-HSA-2243935 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-2243935.1 COSMIC COSV62571334 COSMIC COSM34142 GENE ONTOLOGY GO:0004674 gene ontology term for cellular function MI MI:0355 Same Catalyst Activity Reactome Database ID Release 81 2399974 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=2399974 Reactome Database ID Release 81 2400001 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=2400001 Reactome R-HSA-2400001 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-2400001.1 10485710 Pubmed 1999 NF-kappaB activation by tumour necrosis factor requires the Akt serine-threonine kinase Ozes, ON Mayo, LD Gustin, JA Pfeffer, SR Pfeffer, LM Donner, DB Nature 401:82-5