Sacks D B, Mazus B
Department of Pathology, Brigham & Women's Hospital. Boston, MA 02115.
Biochem Mol Biol Int. 1994 Sep;34(2):251-9.
Calmodulin is an in vitro substrate for casein kinase II and is also reported to inhibit casein kinase II activity in rat liver nuclear extracts. Here we demonstrate that in the presence or absence of Ca2+, calmodulin did not significantly alter either in vitro casein kinase II activity or autophosphorylation of its beta-subunit. In contrast, Ca2+ inhibited in a dose-dependent manner both casein kinase II activity and casein kinase II-catalysed calmodulin phosphorylation. These data indicate that calmodulin does not directly inhibit casein kinase II activity, but casein kinase II is sensitive to physiologic Ca2+ concentrations.
钙调蛋白是酪蛋白激酶II的一种体外底物，据报道它还能抑制大鼠肝核提取物中的酪蛋白激酶II活性。在此我们证明，无论有无Ca2+存在，钙调蛋白均不会显著改变酪蛋白激酶II的体外活性或其β亚基的自身磷酸化。相反，Ca2+以剂量依赖的方式抑制酪蛋白激酶II活性以及酪蛋白激酶II催化的钙调蛋白磷酸化。这些数据表明，钙调蛋白不会直接抑制酪蛋白激酶II活性，但酪蛋白激酶II对生理Ca2+浓度敏感。
