Regulatory Mechanism of M-phase by MPF,M-phase Promoting Factor

MPF、M相促进因子对M相的调节机制

基本信息

批准号：
03405004
负责人：
KISHIMOTO Takeo
金额：
$ 14.02万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

MPF (M-phase promoting factor), which is composed of the p34^<cdc2>/cyclin B complex, cdc2 kinase, governs M-phase in all eukaryotic cells. In this project, we studied how M-phase is executed by cdc2 kinase, and obtained following results.1.We developed a new method to purify cdc2 kinase at high performance by modifying p13^<sucl>-affinity chromatography. This enabled us to analyze the function of cdc2 kinase in inducing various M-phase events.2.At G2/M-phase border, the inactive form of p34^<cdc2>/cyclin B complex localizes in the cytoplasm. The complex is transformed to active form in the cytoplasm at the transition to M-phase. Thereafter, a part of the complex moves into nucleus, while other associates with mitotic apparatus. These specific localizations of the complex might support its specific function to execute M-phase within a cell.3.In contrast to the previous belief that histone H1 phosphorylation by cdc2 kinase plays a key role in chromosome condensation, condensation occurs normally even in the chromatins lacking histone H1. This suggests the presence of an unknown major target of cdc2 kinase for chromosome condensation other than histone H1.4.The p34^<cdc2/>cyclin B complex associates with a microtubule via the binding between cyclin B component and the prolin-rich region of MAP4. In such a complex, cdc2 kinase phosphorylates MAP4 to decrease its microtubule-stabilizing ability, resulting in increased dynamic instability of an individual microtubule. This effect of cdc2 kinase appears to contribute to form metaphase spindle.

由p34^<cdc2>/cyclin B复合物Cdc2激酶组成的MPF（M相促进因子）控制所有真核细胞中的M期。在这个项目中，我们研究了M相如何由Cdc2激酶执行，并获得了遵循结果。1。我们开发了一种新方法，通过修改P13^<Sucl>亲属色谱法净化Cdc2激酶，以高性能净化Cdc2激酶。这使我们能够分析Cdc2激酶在诱导各种M期事件中的功能。2.ATG2/M期边界，p34^<cdc2>/cyclin B复合物的不活跃形式位于细胞质中。该复合物在过渡到M期的细胞质中转化为活性形式。此后，该复合物的一部分进入核，而其他与有丝分裂设备相关。该复合物的这些特定位置可能支持其特定功能以在细胞内执行M期。3。与先前的信念相反：先前的信念是，Cdc2激酶在染色体凝结中磷酸化的组蛋白H1磷酸化在染色体凝结中起着关键作用，即使在缺乏组蛋白H1的染色剂中，凝结也通常也发生。这表明除组蛋白H1.4以外，还存在Cdc2激酶的未知主要靶标，这些染色体凝结酶是通过细胞周期蛋白B成分与MAP4富含刺的刺激区域之间的结合，而不是组蛋白H1.4。在如此复杂的Cdc2激酶中，CDC2激酶磷酸化MAP4以降低其微管稳定能力，从而导致单个微管的动态不稳定性增加。 Cdc2激酶的这种作用似乎有助于形成中期纺锤体。