Translation initiation: adept at adapting.
Initiation of protein synthesis requires both an mRNA and the initiator methionyl (Met)-tRNA to be bound to the ribosome. Most mRNAs are recruited to the ribosome through recognition of the 5' m7G cap by a group of proteins referred to as the cap-binding complex or eIF4F. Evidence is accumulating that eIF4G, the largest subunit of the cap-binding complex, serves as a central adapter by binding to various translation factors and regulators. Other translation factors also have modular structures that facilitate multiple protein-protein interactions, which suggests that adapter functions are common among the translation initiation factors. By linking different regulatory domains to a conserved eIF2-kinase domain, cells adapt to stress and changing growth conditions by altering the translational capacity through phosphorylation of eIF2, which mediates the binding of the initiator Met-tRNA to the ribosome.
Dever
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Laboratory of Eukaryotic Gene Regulation, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-2716, USA. tdever@box-t.nih.gov
D039603:Eukaryotic Initiation Factor-4G; D018384:Oxidative Stress; D010448:Peptide Initiation Factors / Q000502:physiology; D014176:Protein Biosynthesis; D019892:eIF-2 Kinase / Q000378:metabolism
D039603:Eukaryotic Initiation Factor-4G; D010448:Peptide Initiation Factors; D019892:eIF-2 Kinase