Direct evidence of in vitro phosphorylation-dephosphorylation of the estradiol-17 beta receptor. Role of Ca2+-calmodulin in the activation of hormone binding sites.
The calf uterus estradiol-17 beta receptor is a phosphoprotein and its hormone binding activity is regulated by two endogenous enzymes both of which have been purified and characterized in detail: a nuclear phosphatase that inactivates the hormone binding sites of the receptor, and a cytosol kinase that activates these sites. Here we report that the kinase is stimulated by Ca2+ and calmodulin. Direct evidence is presented that the receptor is phosphorylated by the kinase and dephosphorylated by the phosphatase.
D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D002417:Cattle; D002499:Centrifugation, Density Gradient; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D011959:Receptors, Estradiol; D011960:Receptors, Estrogen / Q000378:metabolism*; D014599:Uterus / Q000378:metabolism
D002147:Calmodulin; D011959:Receptors, Estradiol; D011960:Receptors, Estrogen; D011494:Protein Kinases; D010744:Phosphoric Monoester Hydrolases; D002118:Calcium