Phosphorylation of a 43 kdaltons protein from rat heart by a calmodulin-dependent protein kinase.
The Ca2+ -dependent phosphorylation of proteins has been recognized as a major regulatory mechanism of biological processes. In the heart, protein kinases that are activated by Ca2+ include phosphorylase kinase, myosin light chain kinase, phospholamban kinase [review in 4], and the kinases responsible for phosphorylation of endogenous proteins in the membrane [11] and soluble [6] fractions of the cell. All of these Ca2+-dependent enzymes require the presence, either as an enzyme subunit or as a cofactor, of calmodulin, a Ca2+-binding protein which is involved in various other Ca2+-requiring reactions or processes [review in 3]. We demonstrate here the presence, in the rat heart, of a soluble calmodulin-dependent protein kinase which seems different from those already described in this tissue. The substrate for this enzyme is a 43 kdaltons protein, present in the same soluble fraction.
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D008297:Male; D008970:Molecular Weight; D009206:Myocardium / Q000201:enzymology*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D002135:Calcium-Binding Proteins; D002147:Calmodulin; D011494:Protein Kinases