Translational controls impinging on the 5'-untranslated region and initiation factor proteins.
Translation of eukaryotic mRNAs is generally initiated by the scanning ribosome mechanism. This can be downregulated by high affinity protein binding to cap-proximal RNA motifs. Translation can also be regulated by short open reading frames within the 5' -untranslated region. A key factor for initiation is elF4F, in which one of the polypeptide chains, elF4G, seems to have a bridging function and binds three other factors at separate sites: elF4E (the cap-binding factor), the helicase elF4A, and elF3, which also interacts with 40S ribosomal subunits. Initiation is regulated by the MAP kinase and rapamycin-sensitive signalling pathways, which control phosphorylation of elF4E and 4E-BP1, a protein which in the dephosphorylated form binds and sequesters elF4E.
Jackson
R J
RJ
Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK. rjj@mole.bio.cam.ac.uk
Wickens
M
M
D000818:Animals; D001665:Binding Sites; D039562:Eukaryotic Initiation Factor-4F; D039603:Eukaryotic Initiation Factor-4G; D016366:Open Reading Frames; D010442:Peptide Chain Initiation, Translational; D010448:Peptide Initiation Factors / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D014176:Protein Biosynthesis; D011487:Protein Conformation; D016601:RNA-Binding Proteins; D012270:Ribosomes
D039562:Eukaryotic Initiation Factor-4F; D039603:Eukaryotic Initiation Factor-4G; D010448:Peptide Initiation Factors; D016601:RNA-Binding Proteins