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EIF4E
Eukaryotic translation initiation factor 4E, also known as eIF4E, is a protein that in humans is encoded by the ''EIF4E'' gene. Structure and function Most eukaryotic cellular mRNAs are blocked at their 5'-ends with the 7-methyl- guanosine five-prime cap structure, m7GpppX (where X is any nucleotide). This structure is involved in several cellular processes including enhanced translational efficiency, splicing, mRNA stability, and RNA nuclear export. eIF4E is a eukaryotic translation initiation factor involved in directing ribosomes to the cap structure of mRNAs. It is a 24-kD polypeptide that exists as both a free form and as part of the eIF4F pre-initiation complex. Almost all cellular mRNA require eIF4E in order to be translated into protein. The eIF4E polypeptide is the rate-limiting component of the eukaryotic translation apparatus and is involved in the mRNA-ribosome binding step of eukaryotic protein synthesis. The other subunits of eIF4F are a 47-kD polypeptide, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4E With 7MetGTP
Eukaryotic translation initiation factor 4E, also known as eIF4E, is a protein that in humans is encoded by the ''EIF4E'' gene. Structure and function Most eukaryotic cellular mRNAs are blocked at their 5'-ends with the 7-methyl-guanosine five-prime cap structure, m7GpppX (where X is any nucleotide). This structure is involved in several cellular processes including enhanced translational efficiency, splicing, mRNA stability, and RNA nuclear export. eIF4E is a eukaryotic translation initiation factor involved in directing ribosomes to the cap structure of mRNAs. It is a 24-kD polypeptide that exists as both a free form and as part of the eIF4F pre-initiation complex. Almost all cellular mRNA require eIF4E in order to be translated into protein. The eIF4E polypeptide is the rate-limiting component of the eukaryotic translation apparatus and is involved in the mRNA-ribosome binding step of eukaryotic protein synthesis. The other subunits of eIF4F are a 47-kD polypeptide, term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4F
Eukaryotic initiation factor 4F (eIF4F) is a heterotrimeric protein complex that binds the 5' cap of messenger RNAs (mRNAs) to promote eukaryotic translation initiation. The eIF4F complex is composed of three non-identical subunits: the DEAD-box RNA helicase eIF4A, the cap-binding protein eIF4E, and the large "scaffold" protein eIF4G. The mammalian eIF4F complex was first described in 1983, and has been a major area of study into the molecular mechanisms of cap-dependent translation initiation ever since. Function eIF4F is important for recruiting the small ribosomal subunit (40S) to the 5' cap of mRNAs during cap-dependent translation initiation. Components of the complex are also involved in cap-independent translation initiation; for instance, certain viral proteases cleave eIF4G to remove the eIF4E-binding region, thus inhibiting cap-dependent translation. Structure Structures of eIF4F components have been solved individually and as partial complexes by a variety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4ENIF1
Eukaryotic translation initiation factor 4E transporter is a protein that in humans is encoded by the ''EIF4ENIF1'' gene. The protein encoded by this gene is a nucleocytoplasmic shuttle protein for the translation initiation factor eIF4E. This shuttle protein interacts with the importin alpha-beta complex to mediate nuclear import of eIF4E. It is predominantly cytoplasmic;its own nuclear import is regulated by a nuclear localization signal and nuclear export signals. Interactions EIF4ENIF1 has been shown to interact with EIF4E. References Further reading * * * * * * * * * * * * {{gene-22-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4A1
Eukaryotic initiation factor 4A-I (also known as eIF4A1 or DDX2A) is a 46 kDa cytosolic protein that, in humans, is encoded by the ''EIF4A1'' gene, which is located on chromosome 17. It is the most prevalent member of the eIF4A family of ATP-dependant RNA helicases, and plays a critical role in the initiation of cap-dependent eukaryotic protein translation as a component of the eIF4F translation initiation complex. eIF4A1 unwinds the secondary structure of RNA within the 5'-UTR of mRNA, a critical step necessary for the recruitment of the 43S preinitiation complex, and thus the translation of protein in eukaryotes. It was first characterized in 1982 by Grifo, ''et al.'', who purified it from rabbit reticulocyte lysate. Background The regulation of the translation of mRNA transcripts into protein is one of the best ways that a cell can alter its response to its environment, as changes to the transcription of genes often takes considerably more time to be enacted. Protein t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Five-prime Cap
In molecular biology, the five-prime cap (5′ cap) is a specially altered nucleotide on the 5′ end of some primary transcripts such as precursor messenger RNA. This process, known as mRNA capping, is highly regulated and vital in the creation of stable and mature messenger RNA able to undergo translation during protein synthesis. Mitochondrial mRNA and chloroplastic mRNA are not capped. Structure In eukaryotes, the 5′ cap (cap-0), found on the 5′ end of an mRNA molecule, consists of a guanine nucleotide connected to mRNA via an unusual 5′ to 5′ triphosphate linkage. This guanosine is methylated on the 7 position directly after capping ''in vivo'' by a methyltransferase. It is referred to as a 7-methylguanylate cap, abbreviated m7G. In multicellular eukaryotes and some viruses, further modifications exist, including the methylation of the 2′ hydroxy-groups of the first 2 ribose sugars of the 5′ end of the mRNA. cap-1 has a methylated 2′-hydroxy grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4EBP3
Eukaryotic translation initiation factor 4E-binding protein 3 is a protein that in humans is encoded by the ''EIF4EBP3'' gene. Function This gene encodes a member of the EIF4EBP family which derives its name from proteins that bind to eukaryotic initiation factor 4E and that prevent its assembly into EIF4F. Co-transcription of this gene and the neighboring upstream gene (MASK) generates a transcript (MASK-BP3) which encodes a fusion protein composed of the MASK protein sequence for the majority of the protein and a different C-terminus due to an alternate reading frame for the EIF4EBP3 segments. Interactions EIF4EBP3 has been shown to interact with EIF4E Eukaryotic translation initiation factor 4E, also known as eIF4E, is a protein that in humans is encoded by the ''EIF4E'' gene. Structure and function Most eukaryotic cellular mRNAs are blocked at their 5'-ends with the 7-methyl- guanosine .... References Further reading * * * * * {{refend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4EBP1
Eukaryotic translation initiation factor 4E-binding protein 1 (also known as 4E-BP1) is a protein that in humans is encoded by the ''EIF4EBP1'' gene. Function This gene encodes one member of a family of translation repressor proteins. The protein directly interacts with eukaryotic translation initiation factor 4E (eIF4E), which is a limiting component of the multisubunit complex that recruits 40S ribosomal subunits to the 5' end of mRNAs. Interaction of this protein with eIF4E inhibits complex assembly and represses translation. This protein is phosphorylated in response to various signals including UV irradiation and insulin signaling, resulting in its dissociation from eIF4E and activation of cap-dependent mRNA translation. Interactions EIF4EBP1 has been shown to interact with: * EIF4E, * KIAA1303, and * Mammalian target of rapamycin The mammalian target of rapamycin (mTOR), also referred to as the mechanistic target of rapamycin, and sometimes called FK506-binding pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4EBP2
Eukaryotic translation initiation factor 4E-binding protein 2 is a protein that in humans is encoded by the ''EIF4EBP2'' gene. Animal studies EIF4EBP2 knockout mice have been used as an animal model of autism. Mice without the Eif4ebp2 gene exhibited autism-like symptoms, including poor social interaction, altered communication and repetitive behaviors. Knockout mice have high levels of Neuroligins. Interactions EIF4EBP2 has been shown to interact with EIF4E Eukaryotic translation initiation factor 4E, also known as eIF4E, is a protein that in humans is encoded by the ''EIF4E'' gene. Structure and function Most eukaryotic cellular mRNAs are blocked at their 5'-ends with the 7-methyl- guanosine .... References Further reading * * * * * * {{Gene-10-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4G
Eukaryotic translation initiation factor 4 G (eIF4G) is a protein involved in eukaryotic translation initiation and is a component of the eIF4F cap-binding complex. Orthologs of eIF4G have been studied in multiple species, including humans, yeast, and wheat. However, eIF4G is exclusively found in domain Eukarya, and not in domains Bacteria or Archaea, which do not have capped mRNA. As such, eIF4G structure and function may vary between species, although the human EIF4G1 has been the focus of extensive studies. (Other human paralogs are EIF4G2 and EIF4G3.) Across species, eIF4G strongly associates with eIF4E, the protein that directly binds the mRNA cap. Together with the RNA helicase protein eIF4A, these form the eIF4F complex. Within the cell eIF4G is found primarily in the cytoplasm, usually bound to eIF4E; however, it is also found in the nucleus, where its function is unknown. It may have a role in nonsense-mediated decay. History eIF4G stands for eukaryotic initia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF4G2
Eukaryotic translation initiation factor 4 gamma 2 (also called p97, NAT1, and DAP-5) is a protein that in humans is encoded by the ''EIF4G2'' gene. Function Translation initiation is mediated by specific recognition of the cap structure by eukaryotic translation initiation factor 4F (eIF4F), which is a cap binding protein complex that consists of three subunits: eIF4A, eIF4E and eIF4G. The protein encoded by the eIF4G2 gene shares similarity with the C-terminal region of eIF4G1 that contains the binding sites for eIF4A and eIF3. eIF4G2 additionally contains a binding site for eIF4E at the N-terminus. Unlike eIF4G1, which supports cap-dependent and independent translation, the eIF4G2 gene product functions as a general repressor of translation by forming translationally inactive complexes. In vitro and in vivo studies indicate that translation of this mRNA initiates exclusively at a non-AUG (GUG) codon. Alternatively spliced transcript variants encoding different isoforms of this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Ribosome Entry Site
An internal ribosome entry site, abbreviated IRES, is an RNA element that allows for translation initiation in a cap-independent manner, as part of the greater process of protein synthesis. In eukaryotic translation, initiation typically occurs at the 5' end of mRNA molecules, since 5' cap recognition is required for the assembly of the initiation complex. The location for IRES elements is often in the 5'UTR, but can also occur elsewhere in mRNAs. History IRES sequences were first discovered in 1988 in the poliovirus (PV) and encephalomyocarditis virus (EMCV) RNA genomes in the labs of Nahum Sonenberg and Eckard Wimmer, respectively. They are described as distinct regions of RNA molecules that are able to recruit the eukaryotic ribosome to the mRNA. This process is also known as cap-independent translation. It has been shown that IRES elements have a distinct secondary or even tertiary structure, but similar structural features at the levels of either primary or secondary str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
