Saccharomyces cerevisiae elongation factor 2 is phosphorylated by an endogenous kinase.
Mammalian cells contain a Ca2+/calmodulin-dependent protein kinase that specifically phosphorylates and inactivates elongation factor 2 (EF-2) in response to hormones and other agents which increase intracellular Ca2+ concentrations. Therefore, it has been proposed that the rate of translation in mammals is regulated by EF-2 phosphorylation. In the present study, EF-2 purified from the yeast Saccharomyces cerevisiae is shown to be a substrate for the mammalian EF-2 kinase. Furthermore, evidence was obtained using two-dimensional gel electrophoresis and peptide mapping which suggests that yeast EF-2 is a substrate for an endogenous kinase which phosphorylates the same site as the mammalian EF-2 kinase. Based on these findings, we propose that in yeast as in higher eukaryotes, the protein synthesis elongation cycle is regulated by phosphorylation of EF-2.
Donovan
M G
MG
Department of Biochemistry, University of Minnesota Medical School, Minneapolis 55455.
Bodley
J W
JW
D000818:Animals; D001665:Binding Sites; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002474:Cell-Free System; D054736:Elongation Factor 2 Kinase; D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000502:physiology*; D011817:Rabbits; D012156:Reticulocytes / Q000201:enzymology; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism*; D013379:Substrate Specificity
D020652:Peptide Elongation Factor 2; D010445:Peptide Elongation Factors; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D054736:Elongation Factor 2 Kinase