Phosphorylation of Ribosomal Protein S6

Publisher Website
Google Scholar
Abstract
The time course of S6 phosphorylation and several aspects of protein synthesis were studied in suspension cultures of [human cervical carcinoma] HeLa cells following transfer to fresh medium and serum. The phosphorylation of S6 is not temporally correlated with changes in polypeptide initiation and elongation rates as judged from polysome profiles. Phosphorylation of S6 can be maximal within 30 min after transfer; elongation and initiation rates increase coordinately and more slowly, becoming maximal .apprx. 6 h after transfer, a time at which the net phosphorylation of protein S6 is greatly reduced or negligible. Recruitment of messenger RNA into polysomes is another response to fresh medium and serum; this response occurs almost as rapidly as the phosphorylation of S6. The phosphorylation of S6 may play a role in messenger RNA recruitment.