Rime H, Huchon D, Jessus C, Goris J, Merlevede W, Ozon R
Laboratoire de Physiologie de la Reproduction, Université Pierre et Marie Curie, Paris, France.
Cell Differ Dev. 1990 Jan;29(1):47-58. doi: 10.1016/0922-3371(90)90023-p.
Okadaic acid (OA), a specific inhibitor of protein phosphatases, induces a rapid activation (30 min) of MPF when microinjected into the Xenopus oocyte. Neither protein synthesis inhibitors nor cAMP counteract the action of OA. These results indicate that the inhibition of protein phosphatase(s) is sufficient for the in vivo activation of MPF even after the full activation of cAMP-dependent protein kinase. In all experimental conditions (plus or minus inhibitors of protein synthesis; normal or elevated cAMP levels) OA induces a burst of protein phosphorylation together with the activation of MPF. Cytological analysis shows that OA provokes the breakdown of the nuclear envelope, the depolymerization of lamin and the condensation of the chromosomes. However, no metaphase spindles are organized, indicating that inhibition of protein phosphatases strongly affects the function of the microtubule organizing center.
冈田酸（OA）是一种蛋白磷酸酶的特异性抑制剂，当显微注射到非洲爪蟾卵母细胞中时，能诱导MPF快速激活（30分钟）。蛋白质合成抑制剂和cAMP都不能抵消OA的作用。这些结果表明，即使在cAMP依赖性蛋白激酶完全激活后，蛋白磷酸酶的抑制对于MPF的体内激活也是足够的。在所有实验条件下（加或不加蛋白质合成抑制剂；正常或升高的cAMP水平），OA都会诱导蛋白质磷酸化的爆发以及MPF的激活。细胞学分析表明，OA会引发核膜破裂、核纤层解聚和染色体凝聚。然而，没有形成中期纺锤体，这表明蛋白磷酸酶的抑制强烈影响微管组织中心的功能。
