Phosphorylation of eukaryotic protein synthesis initiation factors.
- 1 January 1978
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 75 (1) , 108-112
- https://doi.org/10.1073/pnas.75.1.108
Abstract
Phosphorylation of eukaryotic initiation factors was examined both in intact cells and in vitro with purified components. Intact rabbit reticulocytes were incubated in a medium containing [32P]phosphate, and 8 initiation factors were isolated and partially purified. The purified factors were analyzed on dodecyl sulfate/polyacrylamide gels and compared with highly purified nonradioactive factors. Significant amounts of radioactivity were found associated with initiation factors eIF-2, polypeptide 2 (MW 53,000); eIF-3, polypeptides 2 and 4 (MW 110,000 and 67,000); and eIF-4B. Purified initiation factors from rabbit reticulocytes were also treated in vitro with [.gamma.-32P]ATP and a cyclic[c]AMP-independent protein kinase isolated from rabbit erythrocytes. Only the factor polypeptides phosphorylated intracellularly were phosphorylated in vitro. The results suggest that the cAMP-independent protein kinase is responsible for the phosphorylation of specific initiation factors in cells active in protein synthesis and that it may play a role in regulating translation.Keywords
This publication has 25 references indexed in Scilit:
- Purification and characterization of initiation factors IF-E4 and IF-E6 from rabbit reticulocytes.Journal of Biological Chemistry, 1977
- Phosphorylation of initiation factor eIF-2 and the control of reticulocyte protein synthesisCell, 1977
- Competition between globin messenger ribonucleic acids for a discriminating initiation factor.Journal of Biological Chemistry, 1977
- International symposium on protein synthesis Summary of Fogarty Center‐NIH Workshop held in Bethesda, Maryland on 18–20 October, 1976FEBS Letters, 1977
- Role of 3':5'-cyclic-AMP-dependent protein kinase in regulation of protein synthesis in reticulocyte lysates.Proceedings of the National Academy of Sciences, 1977
- Partial reaction of peptide initiation inhibited by phosphorylation of either initiation factor eIF-2 or 40S ribosomal proteins.Proceedings of the National Academy of Sciences, 1977
- Phosphorylation in vitro of eukaryotic initiation factors IF-E2 and IF-E3 by protein kinases.Journal of Biological Chemistry, 1976
- Factors involved in initiation of haemoglobin synthesis can be phosphorylated in vitroNature, 1976
- Regulation of protein synthesis in reticulocyte lysates: phosphorylation of methionyl-tRNAf binding factor by protein kinase activity of translational inhibitor isolated from hemedeficient lysates.Proceedings of the National Academy of Sciences, 1976
- Competition between cellular and viral mRNAs in vitro is regulated by a messenger discriminatory initiation factor.Proceedings of the National Academy of Sciences, 1976