Bellé R, Cormier P, Poulhe R, Morales J, Huchon D, Mulner-Lorillon O
Laboratoire de Physiologie de la Reproduction, Université Pierre et Marie Curie, Paris, France.
Int J Dev Biol. 1990 Mar;34(1):111-5.
M-Phase specific protein kinase or cdc2 protein kinase is a component of MPF (M-Phase promoting factor). During meiotic maturation of Xenopus oocytes, cdc2 protein kinase is activated in correlation with MPF activity. A protein phosphorylation cascade takes place involving several protein kinases, among which casein kinase II, and different changes associated with meiosis occur such as germinal vesicle breakdown, chromosome condensation, cytoskeletal reorganization and increase in protein synthesis. Our results provide a biochemical link between cdc2 protein kinase and protein synthesis since they show that the kinase phosphorylates in vitro a p47 protein identified as elongation factor EF1 (gamma subunit) and that the in vitro site of p47 corresponds to the site phosphorylated in vivo. Immunofluorescence showed that the elongation factor (EF1-beta gamma) is localized in the oocyte cortex. Furthermore, they show that cdc2 kinase phosphorylates and activates casein kinase II in vitro, strongly supporting the view that casein kinase II is involved in the phosphorylation cascade originated by cdc2 kinase.
M期特异性蛋白激酶或细胞分裂周期蛋白2（cdc2）蛋白激酶是促成熟因子（MPF）的一个组成部分。在非洲爪蟾卵母细胞减数分裂成熟过程中，cdc2蛋白激酶的激活与MPF活性相关。发生了一个涉及多种蛋白激酶的蛋白磷酸化级联反应，其中包括酪蛋白激酶II，并且出现了与减数分裂相关的不同变化，如生发泡破裂、染色体浓缩、细胞骨架重组以及蛋白质合成增加。我们的结果提供了cdc2蛋白激酶与蛋白质合成之间的生化联系，因为结果表明该激酶在体外可磷酸化一种被鉴定为延伸因子EF1（γ亚基）的p47蛋白，并且p47在体外的磷酸化位点与体内磷酸化位点一致。免疫荧光显示延伸因子（EF1-βγ）定位于卵母细胞皮质。此外，结果表明cdc2激酶在体外可磷酸化并激活酪蛋白激酶II，有力地支持了酪蛋白激酶II参与由cdc2激酶引发的磷酸化级联反应这一观点。
