Structural highlights
Function
[IF4E_YEAST] Recognizes and binds the 7-methylguanosine-containing mRNA cap during an early step in the initiation of protein synthesis and facilitates ribosome binding by inducing the unwinding of the mRNAs secondary structures. [IF4F1_YEAST] Component of the eIF4F complex, which interacts with the mRNA cap structure and serves as an initial point of assembly for the translation apparatus. Stimulates translation by interaction with polyadenylate-binding protein PAB1, bringing the 5'- and 3'-ends of the mRNA in proximity. The formation of this circular mRNP structure appears to be critical for the synergistic effects of the cap and the poly(A) tail in facilitating translation initiation, recycling of ribosomes, and mRNA stability. TIF4631 is probably essential when TIF4632 is missing.[1] [2]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The eukaryotic initiation factor 4G (eIF4G) is the core of a multicomponent switch controlling gene expression at the level of translation initiation. It interacts with the small ribosomal subunit interacting protein, eIF3, and the eIF4E/cap-mRNA complex in order to load the ribosome onto mRNA during cap-dependent translation. We describe the solution structure of the complex between yeast eIF4E/cap and eIF4G (393-490). Binding triggers a coupled folding transition of eIF4G (393-490) and the eIF4E N terminus resulting in a molecular bracelet whereby eIF4G (393-490) forms a right-handed helical ring that wraps around the N terminus of eIF4E. Cofolding allosterically enhances association of eIF4E with the cap and is required for maintenance of optimal growth and polysome distributions in vivo. Our data explain how mRNA, eIF4E, and eIF4G exists as a stable mRNP that may facilitate multiple rounds of ribosomal loading during translation initiation, a key determinant in the overall rate of protein synthesis.
Ribosome loading onto the mRNA cap is driven by conformational coupling between eIF4G and eIF4E.,Gross JD, Moerke NJ, von der Haar T, Lugovskoy AA, Sachs AB, McCarthy JE, Wagner G Cell. 2003 Dec 12;115(6):739-50. PMID:14675538[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Tarun SZ Jr, Wells SE, Deardorff JA, Sachs AB. Translation initiation factor eIF4G mediates in vitro poly(A) tail-dependent translation. Proc Natl Acad Sci U S A. 1997 Aug 19;94(17):9046-51. PMID:9256432
- ↑ Otero LJ, Ashe MP, Sachs AB. The yeast poly(A)-binding protein Pab1p stimulates in vitro poly(A)-dependent and cap-dependent translation by distinct mechanisms. EMBO J. 1999 Jun 1;18(11):3153-63. PMID:10357826 doi:http://dx.doi.org/10.1093/emboj/18.11.3153
- ↑ Gross JD, Moerke NJ, von der Haar T, Lugovskoy AA, Sachs AB, McCarthy JE, Wagner G. Ribosome loading onto the mRNA cap is driven by conformational coupling between eIF4G and eIF4E. Cell. 2003 Dec 12;115(6):739-50. PMID:14675538
