Control of Mitotic Entry by Regulators of Cdc2

描述（由申请人提供）：在所有真核细胞中，进入有丝分裂由细胞周期蛋白依赖性激酶Cdc 2控制。Cdc 2/细胞周期蛋白B复合物由抑制性激酶Myt 1和Wee 1以及活化性磷酸酶Cdc 25控制。虽然一些Cdc 25和Myt 1/Wee 1的调节途径已被确定，这些途径是如何相互联系的，以及上游调制器对这些途径的影响还不完全清楚。为了了解生理刺激和检查点控制途径如何调节G2/M转换，我们必须了解这些不同调节器之间的因果关系和调节相互作用。该建议采用了强大的体外重建系统，有丝分裂条目提供的爪蟾卵提取物调查Cdc 25和Wee 1的调节。在这个建议中，我们解决了几个悬而未决的问题，在G21 M的监管，包括Cdc 25的机制，激活在有丝分裂通过去除绑定14-3-3蛋白，是否Cdc 25定向激活磷酸酶可能是细胞周期调节和不同亚型的Cdc 25可能是差异调节。我们还调查了几个候选调节Wee 1，包括激酶PIx和甲基转移酶，Hsl 7。我们的长期目标是获得控制进入有丝分裂的分子事件的机制的理解。

DESCRIPTION (provided by applicant): In all eukaryotic cells, entry into mitosis is controlled by the Cyclin-dependent kinase, Cdc2. Cdc2/Cyclin B complexes are controlled by the inhibitory kinases, Myt1 and Wee1 and by the activating phosphatase, Cdc25. Although a number of Cdc25 and Myt1/Wee1-regulatory pathways have been identified, how these pathways are interconnected and which upstream modulators impinge on these pathways is not yet entirely clear. To understand how physiological stimuli and checkpoint control pathways regulate the G2/M transition, it is essential that we understand the causal connections and regulatory interplays between these diverse regulators. This proposal employs the powerful in vitro reconstitution system for mitotic entry provided by Xenopus egg extracts to investigate Cdc25 and Wee1 regulation. In this proposal we address several outstanding issues in G21M regulation, including the mechanism by which Cdc25 is activated at mitosis through removal of bound 14-3-3 proteins, whether Cdc25-directed activating phosphatases may be cell cycle regulated and how different isoforms of Cdc25 may be differentially regulated. We also investigate several candidate regulators of Wee1, including the kinase PIx and the methyltransferase, Hsl7. Our long-term objective is to obtain a mechanistic understanding of the molecular events that control entry into mitosis.