Protamine kinase phosphorylates eukaryotic protein synthesis initiation factor 4E.
Up to 1 mol of phosphoryl groups was incorporated per mol of eukaryotic protein synthesis initiation factor (eIF) 4E following incubation of purified preparations of this factor with purified preparations of a protamine kinase from bovine kidney cytosol. By contrast, purified preparations of two forms of mitogen-activated protein kinase, casein kinase II and two forms of a distinct autophosphorylation-activated protein kinase exhibited little activity, if any, with eIF-4E. Together with previous observations, the results indicate that the protamine kinase could contribute to the insulin-stimulated phosphorylation of eIF-4E.
Amick
G D
GD
Department of Biological Sciences, University of South Carolina, Columbia 29208.
Damuni
Z
Z
D000818:Animals; D002417:Cattle; D039561:Eukaryotic Initiation Factor-4E; D007668:Kidney / Q000201:enzymology / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D006656:Protamine Kinase; D011494:Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity
D039561:Eukaryotic Initiation Factor-4E; D010448:Peptide Initiation Factors; D011494:Protein Kinases; D006656:Protamine Kinase