Insulin protein biosynthesis regulation

Fig. 1.57. Model of the regulation of translation by insulin. Insulin ( and other growth factors) activates the Akt kinase pathway (see ch. 10), whose final result is the phosphorylation of 4E-BPl, a regulatory protein of translation initiation. The 4E-BP1 protein inactivates the initation factor eIF-4E by complex formation. eIE-4E is required, together with the proteins eIE-4A and p220, for the binding of the 40S subunit of the ribosome to the cap structure of the mRNA. If the 4E-BP1 protein becomes phosphorylated as a result of insulin-mediated activation of the PI3 kinase/Akt kinase cascade, then eIE-4E is liberated from the inactive eIP-4E 4E-BPl complex and protein biosynthesis can begin.

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