Protein synthesis is mediated via numerous molecules including the ribosome, mRNA, tRNAs, as well as translation initiation, elongation and release factors. Some of these factors play several roles throughout the entire process to ensure proper assembly of the preinitiation complex on the right mRNA, accurate selection of the initiation codon, errorless production of the encoded polypeptide and its proper termination. Perhaps, the most intriguing of these multitasking factors is the eukaryotic initiation factor eIF3. Recent evidence strongly suggests that this factor, which coordinates the progress of most of the initiation steps, does not come off the initiation complex upon subunit joining, but instead it remains bound to 80S ribosomes and gradually falls off during the first few elongation cycles to: (1) promote resumption of scanning on the same mRNA molecule for reinitiation downstream-in case of translation of upstream ORFs short enough to preserve eIF3 bound; or (2) come back during termination on long ORFs to fine tune its fidelity or, if signaled, promote programmed stop codon readthrough. Here, we unite recent structural views of the eIF3-40S complex and discus all known eIF3 roles to provide a broad picture of the eIF3's impact on translational control in eukaryotic cells.

• MeSH
• Eukaryotic Initiation Factor-3 chemistry   genetics   metabolism   MeSH
• Protein Conformation * MeSH
• Humans MeSH
• RNA, Messenger genetics   metabolism   MeSH
• Models, Molecular MeSH
• Protein Subunits chemistry   genetics   metabolism   MeSH
• Protein Biosynthesis * MeSH
• Ribosomes genetics   metabolism   MeSH
• Saccharomyces cerevisiae Proteins chemistry   genetics   metabolism   MeSH
• Protein Binding MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Eukaryotic Initiation Factor-3 MeSH
• RNA, Messenger MeSH
• Protein Subunits MeSH
• Saccharomyces cerevisiae Proteins MeSH