Maller J L, Krebs E G
J Biol Chem. 1977 Mar 10;252(5):1712-8.
Ripe Xenopus oocytes in first meiotic prophase when incubated with progesterone in vitro progress synchronously in 3 to 5 h without interphase to second meiotic metaphase where they remain until fertilization or activation. Using highly purified preparations of regulatory and catalytic subunits of adenosine 3':5'-monophosphate-dependent protein kinase from muscle, this progesterone-stimulated cell division sequence was found to be inhibited by microinjection of the catalytic subunit and induced directly in the absence of progesterone after microinjection of regulatory subunit. Dose-response curves revealed that half-maximal effects of regulatory and catalytic subunits occurred at an internal concentration of approximately 0.1 muM. These results indicate that the catalytic subunit is necessary and sufficient to block progesterone-stimulated meiotic cell division. Other experiments revealed that the catalytic subunit was inhibitory only during the first hour after progesterone exposure, suggesting that initial steps in meiotic cell division are affected. Control experiments demonstrate that the muscle cAMP-dependent protein kinase subunits may interact with the endogenous oocyte protein kinase. The results support a model in which meiotic cell division is regulated by a phosphoprotein subject to control by cAMP-dependent protein kinase.
处于第一次减数分裂前期的成熟非洲爪蟾卵母细胞，在体外与孕酮一起孵育时，会在3至5小时内同步进展，不经过间期直接进入第二次减数分裂中期，并在受精或激活前一直保持在该阶段。使用从肌肉中高度纯化的3':5'-环磷酸腺苷依赖性蛋白激酶的调节亚基和催化亚基制剂，发现这种孕酮刺激的细胞分裂序列会被催化亚基的显微注射所抑制，而在显微注射调节亚基后，在没有孕酮的情况下会直接诱导该序列发生。剂量反应曲线显示，调节亚基和催化亚基的半数最大效应发生在内部浓度约为0.1μM时。这些结果表明，催化亚基对于阻断孕酮刺激的减数分裂细胞分裂是必要且充分的。其他实验表明，催化亚基仅在孕酮暴露后的第一小时内具有抑制作用，这表明减数分裂细胞分裂的初始步骤受到了影响。对照实验表明，肌肉cAMP依赖性蛋白激酶亚基可能与内源性卵母细胞蛋白激酶相互作用。这些结果支持了一个模型，即减数分裂细胞分裂由一种受cAMP依赖性蛋白激酶控制的磷蛋白调节。
