P34CDC2 AND CELL CYCLE CONTROL

这项提议的长期目标是理解如何进入 进入有丝分裂是在正常的细胞周期中调节的(有丝分裂 控制)，以及如何防止进入有丝分裂时 检测到损坏的DNA(G2检查点控制)。在真核生物中， 进入有丝分裂是由协同和对立调节的 几种不同的蛋白激酶和蛋白质的活性 磷酸酶。这种级联作用集中在一种丝氨酸/苏氨酸--Cdc2上 细胞进入有丝分裂所需的蛋白激酶。二 Cdc2氨基末端的相邻氨基酸(苏氨酸 14和酪氨酸15)已被证明是 调节Cdc2的激酶活性。这些蛋白的磷酸化 残基使Cdc2保持非活性状态，直到适当的 细胞周期中的时间。在人类中，Weel和Myt1蛋白激酶 调节酪氨酸15和苏氨酸14上的CDC2的磷酸化，而 CDc25C蛋白磷酸酶使Thr 14和Thr 14和Thr 14上的CDc2去磷酸化 Tyr15.Weel和CDC25C都与14-3-3蛋白相互作用，并在 CDC25C，14-3-3P结合的情况负调节功能 Cd_(25)C与Cd_2的相互作用。旨在阐明以下问题的研究 Weel和Myt1蛋白在细胞周期中的调控 都被提出了。此外，Weel和Myt1的激酶将是 在人类细胞中在功能上有所区别。所做的贡献 14-3-3蛋白到G2检查点控制将在两个 哺乳动物系统和分裂酵母中的裂殖酵母 庞贝。最后，将进行研究以阐明 DNA损伤后G2细胞周期停滞的机制基础 因为许多癌症都不能用现有的治疗方法治愈 在伯爵阶段也不容易分离，有必要确定 既可用作诊断探针又可用作 治疗靶点。这项提案中的研究概要 研究细胞周期调控和G2检查点的基本机制 控制力。参与这些途径的蛋白质可能在一天内被用作 诊断标记物或作为设计抗增殖药物的靶点 毒品。

The long term objective of this proposal is to understand how entry into mitosis is regulated during a normal cell cycle (mitotic control) and how entry into mitosis is prevented when unreplicated or damaged DNA is detected (G2 checkpoint control). In eukaryotes, entry into mitosis is regulated by the synergistic and opposing activities of several distinct protein kinases and protein phosphatases. This cascade converges on Cdc2, a serine/threonine protein kinase required for the entry of cells into mitosis. Two neighboring amino acids within the amino terminus of Cdc2 (threonine 14 and tyrosine 15) have been shown to be critical elements in regulating the kinase activity of Cdc2. Phosphorylation of these residues maintains Cdc2 in an inactive state until the appropriate time in the cell cycle. In humans, the Weel and Myt1 protein kinases regulate the phosphorylation of Cdc2 on Tyr 15 and Thr 14 whereas the Cdc25C protein phosphatase dephosphorylates Cdc2 on both Thr 14 and Tyr15. Both Weel and Cdc25C interact with 14-3-3 proteins and in the case of Cdc25C, 14-3-3p binding negatively regulates the functional interactions between Cdc25C and Cdc2. Studies aimed at elucidating how the Weel and Myt1 kinases are regulated throughout the cell cycle are proposed. In addition, the Weel and Myt1 kinases will be functionally distinguished in human cells. The contribution made by 14-3-3 proteins to G2 checkpoint control will be examined in both mammalian systems and in the fission yeast, Schizosaccharomyces pombe. Finally studies will be performed to elucidate the mechanistic basis of G2 cell cycle arrest following DNA damage because many cancers are neither curable using existing strategies nor readily detachable at the earl stages there is a need to identify new targets that can be used both as diagnostic probes and as therapeutic targets. The studies outline in this proposal investigate basic mechanisms of cell cycle control and G2 checkpoint control. Proteins involved in these pathways may on day be used as diagnostic markers or as targets for designing anti-proliferative drugs.