InterPro domain: IPR024675

This entry represents a domain of approximately 130 amino acids in length found at the N terminus of eukaryotic translation initiation factor 3 subunit G. This domain is commonly found in association with the RNA recognition domain PF00076 .

At least eleven different protein factors are involved in initiation of protein synthesis in eukaryotes. Binding of initiator tRNA and mRNA to the 40S subunit requires the presence of the translation initiation factors eIF-2 and eIF-3, with eIF-3 being particularly important for 80S ribosome dissociation and mRNA binding [ 1 ]. eIF-3 is the most complex translation inititation factor, consisting of about 13 putative subunits and having a molecular weight of between 550 - 700kDa in mammalian cells. Subunits are designated eIF-3a - eIF-3m; the large number of subunits means that the interactions between the individual subunits that make up the eIF-3 complex are complex and varied.

eIF-3G (also termed eIF-3 subunit 4, eIF-3-delta, eIF3-p42, or eIF3-p44) is the RNA-binding subunit of eIF3. Subunit eIF-3G binds 18 S rRNA and beta-globin mRNA, and therefore appears to be a nonspecific RNA-binding protein. It is one of the cytosolic targets and interacts with mature apoptosis-inducing factor (AIF). The yeast orthologue is known as eIF3-p33; it plays an important role in the initiation phase of protein synthesis in yeast. It binds both mRNA and rRNA fragments due to an RNA recognition motif near its C terminus [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ].

1. Eukaryotic initiation factors eIF-2 and eIF-3: interactions, structure and localization in ribosomal initiation complexes. Biochimie 73, 1007-19
2. Reconstitution reveals the functional core of mammalian eIF3. EMBO J. 26, 3373-83
3. Identification of partners of TIF34, a component of the yeast eIF3 complex, required for cell proliferation and translation initiation. EMBO J. 16, 6812-22
4. Characterization of the p33 subunit of eukaryotic translation initiation factor-3 from Saccharomyces cerevisiae. J. Biol. Chem. 274, 8546-53
5. The RNA recognition motif of eukaryotic translation initiation factor 3g (eIF3g) is required for resumption of scanning of posttermination ribosomes for reinitiation on GCN4 and together with eIF3i stimulates linear scanning. Mol. Cell. Biol. 30, 4671-86
6. Structural roles for human translation factor eIF3 in initiation of protein synthesis. Science 310, 1513-5
7. Mass spectrometry reveals modularity and a complete subunit interaction map of the eukaryotic translation factor eIF3. Proc. Natl. Acad. Sci. U.S.A. 105, 18139-44
8. Structural characterization of the human eukaryotic initiation factor 3 protein complex by mass spectrometry. Mol. Cell Proteomics 6, 1135-46
9. Translation initiation factor eIF4G-1 binds to eIF3 through the eIF3e subunit. J. Biol. Chem. 281, 22917-32
10. Apoptosis-inducing factor (AIF) inhibits protein synthesis by interacting with the eukaryotic translation initiation factor 3 subunit p44 (eIF3g). FEBS Lett. 580, 6375-83
11. Binding of eukaryotic initiation factor 3 to ribosomal 40S subunits and its role in ribosomal dissociation and anti-association. RNA 11, 470-86
12. The j-subunit of human translation initiation factor eIF3 is required for the stable binding of eIF3 and its subcomplexes to 40 S ribosomal subunits in vitro. J. Biol. Chem. 279, 8946-56
13. Characterization of eIF3k: a newly discovered subunit of mammalian translation initiation factor elF3. Eur. J. Biochem. 270, 4133-9
14. Cloning and characterization of the p42 subunit of mammalian translation initiation factor 3 (eIF3): demonstration that eIF3 interacts with eIF5 in mammalian cells. Nucleic Acids Res. 27, 1331-7
15. Characterization of cDNAs encoding the p44 and p35 subunits of human translation initiation factor eIF3. J. Biol. Chem. 273, 31901-8