Ca2+-calmodulin-dependent phosphorylation of soluble and nuclear proteins in the rat ovary.
Studies were undertaken to determine if calmodulin-regulated Ca2+-dependent protein kinase system(s) exist in the prepubertal rat ovary. Phosphorylation studies were performed with ovarian cytosol, calmodulin-depleted cytosol, and nuclear extracts. In vitro phosphorylation of endogenous substrate proteins was accomplished by incubation of tissue fractions with [gamma-32P]ATP followed by electrophoretic separation and autoradiographic demonstration of phosphorylated proteins. Calmodulin-dependent phosphorylations of a cytosol protein, mol wt, 95,000, and of three nuclear proteins in the mol wt range of 50,000-60,000, were established by demonstrating: Ca2+ requirement; inhibition by the phenothiazine derivative chlorpromazine; and dependence upon addition of exogenous calmodulin to the calmodulin-depleted cytosol, or to the nuclear extract. These findings demonstrate the presence of rat ovarian cytosol and nuclear Ca2+-calmodulin-dependent protein kinase activities capable of recognizing endogenous substrate proteins.
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D002147:Calmodulin / Q000494:pharmacology*; D002467:Cell Nucleus / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D005260:Female; D007700:Kinetics; D008970:Molecular Weight; D009698:Nucleoproteins / Q000378:metabolism*; D010053:Ovary / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012995:Solubility
D002135:Calcium-Binding Proteins; D002147:Calmodulin; D009698:Nucleoproteins; D011506:Proteins; D011494:Protein Kinases; D002118:Calcium