DEPHOSPHORYLATION AND ACTIVATION OF XENOPUS-P34CDC2 PROTEIN-KINASE DURING THE CELL-CYCLE
DEPHOSPHORYLATION AND ACTIVATION OF XENOPUS-P34CDC2 PROTEIN-KINASE DURING THE CELL-CYCLE
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DOI：
10.1038/339626a0
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发表时间：
1989-06-22
期刊：
影响因子：
64.8
通讯作者：
MALLER, J
中科院分区：
文献类型：
--
作者：
GAUTIER, J;MATSUKAWA, T;MALLER, J
对裂殖酵母Schizosophyomycespombehave的遗传学研究表明，细胞周期中G2-→ M-期转变所需的关键元件由dc 2+基因编码1 -5。该基因的产物是一种丝氨酸/苏氨酸蛋白激酶，命名为p34 cdc 2，从酵母到man 2在功能上高度保守，相对分子质量为34，000（34 K）。纯化的促成熟因子（MPF）是p34 cdc 2和45 K底物的复合物，出现在G2晚期，足以驱动细胞进入有丝分裂6 -9。该因子已在所有真核细胞中鉴定10，11，并且在体外组蛋白H1是磷酸化的优选底物7，9，12。M期Hl激酶活性的增加与总细胞蛋白磷酸化的大量增加相关，这被认为是MPF激活的结果13 -18。我们发现在非洲爪蟾的细胞周期中，p34 cdc 2的HI激酶活性振荡，最大活性与p34 cdc 2的去磷酸化状态相关。MPF在体外的直接失活伴随着p34 cdc 2的磷酸化和其蛋白激酶活性的降低。
GENETIC studies in the fission yeastSchizosaccharomyces pombehave established that a critical element required for the G2-→ M-phase transition in the cell cycle is encoded by thecdc2+gene1–5. The product of this gene is a serine/threonine protein kinase, designated p34cdc2, that is highly conserved functionally from yeast to man2and has a relative molecular mass of 34,000 (34 K). Purified maturation-promoting factor (MPF) is a complex of p34cdc2and a 45K substrate that appears in late G2 phase and is sufficient to drive cells into mitosis6–9. This factor has been identified in all eukaryotic cells10,11, andin vitrohistone H1 is the preferred substrate for phosphorylation7,9,12. The increase in the activity of HI kinase in M-phase is associated with a large increase in total cell protein phosphorylation which is believed to be a consequence of MPF activation13–18. We show here that the HI kinase activity of p34cdc2oscillates during the cell cycle inXenopus, and maximal activity correlates with the dephosphorylated state of p34cdc2. Direct inactivation of MPFin vitrois accompanied by phosphorylation of p34cdc2and reduction of its protein kinase activity.