Cellular Lifespan and the Telomere Proteome

描述（由申请人提供）：有限的细胞寿命被假设在生物体衰老中起关键作用。尽管人们认为细胞寿命在衰老中的重要性有限，但我们目前对分子过程只有初步的了解。因此，阐明控制细胞寿命的分子机制将对衰老、癌症生物学和组织再生等领域产生深远的影响。在培养物中生长时，正常的人类细胞在进入复制性衰老状态之前分裂有限的次数，在这种状态下，它们仍然有活力，但无法进一步分裂。据推测，这种有限的复制能力导致了与衰老相关的表型，如伤口愈合减少和免疫系统减弱。我们对细胞寿命的兴趣集中在端粒上，端粒是一种由DNA和蛋白质组成的特殊结构，位于线性染色体的末端，因为它在控制细胞寿命方面起着关键作用。该建议将采用一种新的蛋白质组学方法来鉴定端粒结合蛋白。虽然鉴定这些蛋白质非常重要，但描述它们在端粒稳态中的功能对于进一步了解细胞衰老至关重要。我们将使用这些新发现的蛋白质，以及已知与端粒结合的蛋白质，在人类细胞中建立一些抑制因子筛选。我们在基于载体的RNAi系统方面的专业知识使这些研究成为可能。这些后一项研究将使我们不仅能够识别端粒结合蛋白，而且还将使我们能够揭示通过影响端粒的稳态和细胞寿命来影响端粒的信号转导途径的关键成分。目前，我们有几个基于细胞的系统，我们可以解决新蛋白质在端粒稳态和细胞寿命中的功能。我们的基于细胞的系统与我们提出的新的蛋白质发现系统相结合，将被证明是一个强大的武器库，我们将开始了解细胞衰老。了解端粒结构是如何被监测、维持和降解的，将使我们能够描绘衰老的分子机制。一旦我们了解了这个过程，我们就能确定衰老是否在机体衰老中起着致病作用。由于这些原因，详细了解控制细胞衰老的分子机制是至关重要的。

DESCRIPTION (provided by applicant): A limited cellular lifespan is hypothesized to play a crucial role in organismal aging. Despite the putative limited importance of cellular lifespan in aging, we currently have only a rudimentary understanding of the molecular process. Therefore, elucidation of the molecular mechanisms that control cellular lifespan will have far-reaching implications in the fields of aging, cancer biology, and tissue regeneration. When grown in culture, normal human cells divide a limited number of times before entering a state of replicative senescence, in which they remain viable but are unable to divide further. It is postulated that this limited replicative capacity contributes to the phenotypes associated with aging, such as reduced wound healing and a weakened immune system. Our interest in cellular lifespan is focused on the telomere - a specialized structure composed of DNA and proteins, which is located at the end of linear chromosomes - because it plays a key role in controlling cellular lifespan. This proposal will take a novel proteomics approach to identify telomeric binding proteins. While the identification of these proteins will be of great importance, delineation of their function in telomere homeostasis will be paramount to furthering our understanding of cellular aging. We will use these newly identified proteins, and proteins already known to bind the telomere, to set up a number of suppressor screens in human cells. Our expertise in vector-based RNAi systems makes these studies feasible. These latter studies will allow us to not only identify telomere binding proteins, but will also allow us to uncover critical components of the signal transduction pathways that impinge on the telomere by affecting its homeostasis and cellular lifespan. Currently we have several cell-based systems with which we can address the function of new proteins in telomere homeostasis and cellular lifespan. Our cell-based systems combined with the novel protein discovery systems we have proposed will prove to be a powerful arsenal with which we will begin to understand cellular aging. Understanding how telomere structure is monitored, maintained, and degraded will allow us to delineate the molecular mechanisms of senescence. Once we have an understanding of this process, we will be able determine whether senescence plays a causative role in organismal aging. For these reasons, a detailed understanding of the molecular mechanisms governing cellular senescence is critical.