You are studying the effects of insulin addition to cultures of eukaryotic cells at the level of protein synthesis. Your results demonstrate that addition of insulin stimulates protein synthesis concomitant with the phosphorylation of protein S6 of the 40S ribosomal subunit of the ribosome. Which of the following steps in protein synthesis is most likely stimulated when S6 is phosphorylated in this system?

Question

Quizplus · Accepted Answer

Phosphorylation of ribosomal protein S6 is associated with the initiation phase of protein synthesis, enhancing the translation of specific mRNAs.  Translation initiation involves the interactions of eIF-2-GTP, an activated initiator tRNA (met-tRNAmet), and binding to the 40S subunit forming the 43S preinitiation complex. Phosphorylation of the 40S ribosome-associate protein S6 is therefore most likely to be associated with regulation of translation initiation.

You Are Studying the Effects of Insulin Addition to Cultures