Endo Y, Komatsu S, Hirai M, Suzuki S, Shimizu N
Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo.
Nihon Sanka Fujinka Gakkai Zasshi. 1991 Jan;43(1):109-16.
It has been suggested that the Ca2+ and phospholipid dependent protein kinase (protein kinase C; PKC) plays some intermediary roles in the regulation of the zona pellucida-induced acrosome reaction in mouse sperm. We here demonstrated that PKC activity is in the cytosol fraction of mouse sperm and that treatment of sperm with a PKC activator, 12-O-tetradecanoyl phorbol 13-acetate (TPA), induces translocation of PKC to the membrane fraction. Treatment of epididymal sperm with 20 ng/ml TPA or 20 microM of the Ca2+ ionophore A23187 did not induce any specific protein phosphorylation. However, two specific proteins, with molecular weights of 215 kDa and 35 kDa, were significantly phosphorylated when sperm were incubated with A23187 prior to TPA treatment. A similar synergistic effect of TPA and A23187 was observed in Ca2+ accumulation in sperm. We also demonstrated that exogenous PKC purified from human pancreatic cells catalyzes the phosphorylation of these two proteins in vitro as well. The present data support the idea that the activation of PKC and subsequent protein phosphorylation are involved in the regulation of the zona pellucida-induced acrosome reaction.
有人提出，钙和磷脂依赖性蛋白激酶（蛋白激酶C；PKC）在小鼠精子透明带诱导的顶体反应调节中发挥一些中介作用。我们在此证明，PKC活性存在于小鼠精子的胞质溶胶部分，并且用PKC激活剂12-O-十四酰佛波醇13-乙酸酯（TPA）处理精子会诱导PKC转位至膜部分。用20 ng/ml TPA或20 μM钙离子载体A23187处理附睾精子不会诱导任何特异性蛋白磷酸化。然而，当精子在TPA处理前与A23187孵育时，两种分子量分别为215 kDa和35 kDa的特异性蛋白会被显著磷酸化。在精子的钙积累中也观察到了TPA和A23187的类似协同作用。我们还证明，从人胰腺细胞中纯化的外源性PKC在体外也催化这两种蛋白的磷酸化。目前的数据支持这样一种观点，即PKC的激活和随后的蛋白磷酸化参与了透明带诱导的顶体反应的调节。
