Search results for EIF4E

Showing 18 results out of 32

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Protein (4 results from a total of 5)

Identifier: R-HSA-72578
Species: Homo sapiens
Compartment: cytosol
Primary external reference: UniProt: EIF4E: P06730
Identifier: R-HSA-72580
Species: Homo sapiens
Compartment: cytosol
Primary external reference: UniProt: EIF4EBP1: Q13541
Identifier: R-HSA-1678822
Species: Homo sapiens
Compartment: cytosol
Primary external reference: UniProt: EIF4E2: O60573
Identifier: R-HSA-1678824
Species: Homo sapiens
Compartment: cytosol
Primary external reference: UniProt: EIF4E3: Q8N5X7

Interactor (2 results from a total of 2)

Identifier: P06730-1
Species: Homo sapiens
Primary external reference: UniProt: P06730-1
Identifier: O60573-1
Species: Homo sapiens
Primary external reference: UniProt: O60573-1

Reaction (4 results from a total of 15)

Identifier: R-HSA-165708
Species: Homo sapiens
Compartment: cytosol
Phosphorylated EIF4BP1 dissociates from EIF4E.
Identifier: R-HSA-72622
Species: Homo sapiens
Compartment: cytosol
eIF4E gets released from the inactive eIF4E:4EBP complex.
Identifier: R-HSA-9817692
Species: Homo sapiens
Compartment: cytosol
BTG4 binds eIF4E of the mRNA-protein complex (mRNP) and CNOT7 (CAF1) and CNOT8 of the CCR4-NOT RNA deadenylase complex, thereby connecting maternal mRNPs with mRNA degradation (inferred from mouse homologs). The polyadenylate binding protein PABPN1L also mediates binding of BTG4 to mRNA (inferred from mouse homologs). In mouse oocytes lacking BTG4, shortening of mRNA polyadenylate tails, an initial step in mRNA degradation, is impaired and Btg4 KO embryos arrested at the 1-2 cell stage (Yu et al. 2016, Liu et al., 2016, Pasternak et al. 2016). Upon Btg4 siRNA knockdown, mouse oocytes precociously enter anaphase II (Pasternak et al. 2016). Of note, global deadenylation can still occur in mouse oocytes mutant for Btg4 mutant oocytes. However, BTG4 is required for selective gene de-adenylation and production of very short-tailed transcripts in mice (Xiong et al. 2022).
Identifier: R-HSA-1678842
Species: Homo sapiens
Compartment: cytosol
Eukaryotic translation initiation factor 4F (eIF4F) is a protein complex that mediates recruitment of ribosomes to mRNA (Gingras et al. 1999). eIF4F contains complex of cap-binding protein eIF4E, scaffold protein eIF4G, and RNA helicase eIF4A. There are three eIF4E-family members in mammals termed eIF4E-1 (eIF4E), eIF4E2 (4EHP), and eIF4E3, of which both eIF4E and eIF4E3 are able to bind to eIF4G to facilitate translation initiation. However, 4EHP does not interact with eIF4G and thus cannot function in ribosome recruitment. 4EHP competes with eIF4E or eIF4E3 for binding to the RNA 5? cap structure and prevents translation initiation. ISGylated 4EHP has a much higher cap structure binding activity, suggesting a regulatory function of ISGylation in protein translation during immune responses (Okumura et al. 2007, Joshi et al. 2004).

Complex (4 results from a total of 6)

Identifier: R-HSA-72581
Species: Homo sapiens
Compartment: cytosol
Identifier: R-HSA-165697
Species: Homo sapiens
Compartment: cytosol
Identifier: R-HSA-159329
Species: Homo sapiens
Compartment: cytosol
Identifier: R-HSA-429977
Species: Homo sapiens
Compartment: cytosol
mRNA's that are ready for translation have a circular structure caused by interaction between PABP bound to the 3' poly(A) tail and the eIF4E-eIF4G-PAIP complex bound to the 7-methylguanosine cap. The interaction between poly(A)-PABP and the eIF4G-eIF4E complex stimulates affinity of eIF4E for the cap and improves translation.

Set (1 results from a total of 1)

Identifier: R-HSA-1678829
Species: Homo sapiens
Compartment: cytosol

Pathway (2 results from a total of 2)

Identifier: R-HSA-72662
Species: Homo sapiens
Compartment: cytosol
The cap-binding complex is constituted by the initiation factors eIF4A, eIF4G and eIF4E. First, eIF4E must be released from the inactive eIF4E:4E-BP complex. Then eIF4A interacts with eIF4G, and eIF4E binds to the amino-terminal domain of eIF4G, resulting in the formation of the cap-binding complex eIF4F. eIF4A together with eIF4B or eIF4H is thought to unwind RNA secondary structures near the 5'-end of the mRNA. The translation initiation complex is formed when the 43S complex binds the cap-bound mRNA.
Identifier: R-HSA-72613
Species: Homo sapiens
Initiation of translation in the majority of eukaryotic cellular mRNAs depends on the 5'-cap (m7GpppN) and involves ribosomal scanning of the 5' untranslated region (5'-UTR) for an initiating AUG start codon. Therefore, this mechanism is often called cap-dependent translation initiation. Proximity to the cap, as well as the nucleotides surrounding an AUG codon, influence the efficiency of the start site recognition during the scanning process. However, if the recognition site is poor enough, scanning ribosomal subunits will ignore and skip potential starting AUGs, a phenomenon called leaky scanning. Leaky scanning allows a single mRNA to encode several proteins that differ in their amino-termini. Merrick (2010) provides an overview of this process and hghlights several features of it that remain incompletely understood.

Several eukaryotic cell and viral mRNAs initiate translation by an alternative mechanism that involves internal initiation rather than ribosomal scanning. These mRNAs contain complex nucleotide sequences, called internal ribosomal entry sites, where ribosomes bind in a cap-independent manner and start translation at the closest downstream AUG codon.
Initiation on several viral and cellular mRNAs is cap-independent and is mediated by binding of the ribosome to internal ribosome entry site (IRES) elements. These elements are often found in characteristically long structured regions on the 5'-UTR of an mRNA that may or may not have regulatory upstream open reading frames (uORFs). Both of these features on the 5'-end of the mRNA hinder ribosomal scanning, and thus promote a cap-independent translation initiation mechanism. IRESs act as specific translational enhancers that allow translation initiation to occur in response to specific stimuli and under the control of different trans-acting factors, as for example when cap-dependent protein synthesis is shut off during viral infection. Such regulatory elements have been identified in the mRNAs of growth factors, protooncogenes, angiogenesis factors, and apoptosis regulators, which are translated under a variety of stress conditions, including hypoxia, serum deprivation, irradiation and apoptosis. Thus, cap-independent translational control might have evolved to regulate cellular responses in acute but transient stress conditions that would otherwise lead to cell death, while the same mechanism is of major importance for viral mRNAs to bypass the shutting-off of host protein synthesis after infection. Encephalomyocarditis virus (EMCV) and hepatitis C virus exemplify two distinct mechanisms of IRES-mediated initiation. In contrast to cap-dependent initiation, the eIF4A and eIF4G subunits of eIF4F bind immediately upstream of the EMCV initiation codon and promote binding of a 43S complex. Accordingly, EMCV initiation does not involve scanning and does not require eIF1, eIF1A, and the eIF4E subunit of eIF4F. Nonetheless, initiation on some EMCV-like IRESs requires additional non-canonical initiation factors, which alter IRES conformation and promote binding of eIF4A/eIF4G. Initiation on the hepatitis C virus IRES is simpler: a 43S complex containing only eIF2 and eIF3 binds directly to the initiation codon as a result of specific interaction of the IRES and the 40S subunit.

Icon (1 results from a total of 1)

Species: Homo sapiens
Curator: Bruce May
Designer: Cristoffer Sevilla
eIF4E icon
Eukaryotic translation initiation factor 4E
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