Investigation into Mechanisms of CDK1 in Controlling Telomere Stability

描述(申请人提供)：端粒保护染色体末端的完整性，并在细胞和组织衰老中发挥关键作用。端粒的保护作用是通过多种端粒结合蛋白的协同作用来实现的。这些蛋白质的缺乏会损害染色体末端保护，导致不适当的染色体融合或重组，引发细胞早期衰老，削弱人体的正常功能。因此，有必要了解这些蛋白质在端粒上的作用以及这些蛋白质功能失调的后果。维持端粒稳定性的重要蛋白质包括保护素复合体、DNA修复机制、DNA损伤反应蛋白和DNA复制因子。这些蛋白质与端粒DNA之间的精确协调是维持端粒功能所必需的。端粒结合蛋白在复制过程中获得端粒DNA，此时端粒结构发生动态变化，端粒DNA可被各种蛋白质访问。然而，调控这些蛋白质如何访问端粒DNA以及它们如何相互协作实现端粒保护的潜在机制尚不清楚。在我们最近的工作中，我们已经证明了细胞周期蛋白依赖性激酶1(CDK1)，一个控制细胞周期进程的关键激酶，在调节细胞周期进程中起着至关重要的作用。 端粒的结构变化和维持端粒的不稳定性。我们的中心假设是CDK1可能调节细胞周期中端粒的动态结构变化，并控制端粒结合蛋白对端粒DNA的访问。我们将在以下两个目标中检验这一假设。目的1、确定端粒CDK1的磷酸化靶点。目的研究细胞周期超前和滞后端粒蛋白质组成的动态变化，分析CDK1抑制对端粒蛋白质组成的影响。这些研究结果将促进我们对维持端粒完整性和基因组稳定性的机制的理解，从而可以避免与端粒功能障碍导致的过早衰老相关的疾病。

DESCRIPTION (provided by applicant): Telomeres protect the integrity of chromosome ends and play a key role in cellular and organismal aging. The protective function of telomeres is achieved by coordinated actions of multiple telomere-binding proteins. Deficiencies in these proteins impair chromosome end protection and lead to inappropriate chromosome fusions or recombination, triggering early cellular senescence and diminishing normal functions of a human body. It is therefore imperative to understand the roles of these proteins at telomeres and the consequences of dysfunction of these proteins. Proteins important for maintaining telomere stability include shelterin complex, DNA repair machinery, DNA damage response proteins, and DNA replication factors. Precise coordination between these proteins upon their access to telomeric DNA is necessary to achieve the maintenance of functional telomeres. Telomere-binding proteins gain access to telomeric DNA during replication, at which time telomere structure undergoes dynamic changes and telomeric DNA becomes accessible to various proteins. However, the underlying mechanisms regulating how these proteins access telomeric DNA and how they collaborate with each other to achieve telomere protection are poorly understood. In our recent work, we have demonstrated that cyclin-dependent kinase 1 (CDK1), a key kinase controlling the cell cycle progression, plays a crucial role in regulating the structural changes at telomeres and in maintaining telomere instability. Our central hypothesis for this proposal is that CDK1 may regulate the dynamic structural changes of telomeres during the cell cycle and also control the access of telomere-binding proteins to telomeric DNA. We will test this hypothesis in the following two aims. Aim 1, Determine CDK1 phosphorylation targets at telomeres. Aim 2, Characterize the dynamics of protein composition at leading and lagging telomeres during the cell cycle and analyze the effects of CDK1 inhibition on protein composition at telomeres. The findings from these studies will advance our understanding in the mechanism for maintaining telomere integrity and genome stability, and therefore, the diseases associated with dysfunctional telomeres induced premature aging can be avoided.