Molecular Analysis of the Kinetochore-Microtubule Interface

描述(申请人提供)：人体中的每个细胞包含46条不同的染色体，这是一种大的DNA单位，编码了细胞生长、分裂和执行其特殊功能的指令。在有丝分裂期间，当细胞分裂时，这些染色体中的每一条都必须准确地分配给两个新的子细胞。如果这一过程发生错误，即使只有一条染色体，由此产生的子细胞将失去或获得数千个基因和它们包含的指令。这种类型的染色体分离错误可能导致细胞死亡，并被认为是导致肿瘤发生的原因。事实上，超过70%的肿瘤被观察到有异常的染色体数量。除了改变整个染色体数量的错误外，在细胞机械不适当地附着到染色体的情况下，这还可能导致细胞分裂期间的染色体碎裂。这些错误已被证明会导致染色体重排，这也有可能导致细胞转化和肿瘤发生。为了促进有丝分裂过程中DNA的分离，染色体必须与被称为微管的杆状聚合物产生物理连接，微管提供移动染色体的结构和力量。染色体分离的一个关键因素是一个巨大的蛋白质结构，称为着丝粒，它形成了染色体和微管之间的界面。动粒活性的抑制预计将针对癌细胞，同时避免与微管结合化疗药物相关的剂量限制性神经元毒性。确定动粒功能的分子基础对于了解导致肿瘤细胞产生的缺陷过程以及评估诊断和治疗的最佳靶点至关重要。 疾病的威胁。这项拟议的工作将分析动点与人类细胞中纺锤体微管聚合物相互作用的机制。我们将采用并行的细胞和生化方法来分析在动点与微管结合的关键蛋白质。这项工作的一个关键重点不仅是分析单个蛋白质的功能和活性，而且还将测试存在于动点的多种不同蛋白质如何以综合的方式共同作用，以形成与微管的强大相互作用。

DESCRIPTION (provided by applicant): Each cell in the human body contains 46 different chromosomes, large units of DNA that encode instructions for that cell to grow, divide, and carry out its specialized functions. During mitosis, when a cell divides, each of these chromosomes must be accurately distributed to the two new daughter cells. If this process occurs incorrectly for even a single chromosome, the resulting daughter cells will lose or gain thousands of genes and the instructions that they contain. This type of error in chromosome segregation can result in the death of the cell and is thought to contribute to tumorigenesis. Indeed, more than 70% of tumors are observed to have abnormal numbers of chromosomes. In addition to errors that alter whole chromosome numbers, in cases where the cellular machinery makes inappropriate attachments to the chromosomes, this can result in chromosome fragmentation during cell division. These errors have been shown to cause chromosomal rearrangements, which also have the potential to result in cellular transformation and tumorigenesis. To facilitate the segregation of DNA during mitosis, chromosomes must generate physical attachments to rod-like polymers termed microtubules that provide the structure and forces to move the chromosomes. A key player in chromosome segregation is a large proteinaceous structure termed the kinetochore that forms the interface between chromosomes and microtubules. Inhibition of kinetochore activities is predicted to target cancer cells while avoiding the dose-limiting neuronal toxicity associated with microtubule-binding chemotherapeutics. Determining the molecular basis for kinetochore function is crucial to understand the defective processes that can give rise to tumor cells, and to evaluate the best targets for the diagnosis and treatment of disease. The proposed work will analyze the mechanisms by which kinetochores interact with spindle microtubule polymers in human cells. We will take parallel cellular and biochemical approaches to analyze the key proteins that bind to microtubules at kinetochores. A key focus of this work will be not only to analyze the functions and activities of the individual proteins, but also to test how the multiple different proteins that are present at kinetochores act together in a integrated manner to form robust interactions with microtubules.