During eukaryotic protein synthesis, phosphorylation of which of the following is enhanced by insulin?
High-Yield Explanation
Insulin phosphorylates both 4E-binding protein and eIF-4G. The 4F complex consists of eIF-4E (4E), eIF-4A, and eIF-4G. 4E is inactive when bound by one of a family of binding proteins (4E-BPs). Insulin and mitogenic growth polypeptides, or growth factors activate the PI3 kinase/AKT kinase pathways, which activate the mTOR kinase, and results in the phosphorylation of 4E-BP. Phosphorylated 4E-BP dissociates from 4E, and the latter is then able to form the 4F complex and bind to the mRNA cap.