Kinetochore Specification and Function

着丝粒规格及功能

• 批准号: 9214331
• 负责人: Arshad Desai
• 金额: $ 37.62万
• 依托单位: LUDWIG INSTITUTE FOR CANCER RES LTD
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2018-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9214331
• 关键词: Address; Attenuated; Basic Science; Binding; Biological Assay; Caenorhabditis elegans; Cancer cell line; Cell Cycle Progression; Cell division; Cells; Centromere; Chemotherapy-Oncologic Procedure; Chromosomal Instability; Chromosome Segregation; Chromosomes; Complex; Congenital Abnormality; Coupled; Data; Development; Dynein ATPase; Embryonic Development; Engineering; Ensure; Exhibits; Fatigue; Fertility Disorders; Genetic; Genome; Goals; Human; In Vitro; Kinetochores; Lateral; Lead; MXD1 gene; Mad1 protein; Malignant Neoplasms; Measures; Mechanics; Mediating; Microtubules; Mitosis; Mitotic Chromosome; Molecular; Motor; Mutation; Nuclear Pore; Organism; Pathway interactions; Phenotype; Phosphotransferases; Process; Proteins; Recruitment Activity; Role; Set protein; Signal Pathway; Signal Transduction; Sister Chromatid; Site; Work; anaphase-promoting complex; base; cancer cell; chromosome loss; cohesion; daughter cell; defined contribution; design; in vivo; mutant; novel therapeutic intervention; novel therapeutics; prevent; protein complex; public health relevance; scaffold; segregation; therapy resistant; tumorigenesis

DESCRIPTION (provided by applicant): Accurate partitioning of the replicated genome to daughter cells during cell division is essential for the development and propagation of all living organisms. Errors in genome distribution are a hallmark of cancer cells and the machinery involved in this process is targeted in cancer chemotherapy. Thus, elucidating the mechanisms ensuring accurate genome distribution will inform our understanding of the genesis of cancer and guide development of new therapeutic strategies. A major player in genome distribution is the kinetochore, the machine built on the centromere regions of chromosomes during mitosis to generate a dynamic end- coupled interface with spindle microtubules. The mechanics at this interface are tightly integrated with a signaling pathway, termed the spindle checkpoint, which prevents cell cycle progression until all chromosomes are connected to the spindle. Microtubule binding and checkpoint signaling are coordinated at the kinetochore by the conserved Knl1/Mis12 complex/Ndc80 complex (KMN) protein network. Within this protein set, the Ndc80 complex interacts directly with microtubule ends. The work proposed here has three goals: 1) to elucidate the mechanisms ensuring accurate formation of Ndc80-mediated kinetochore-microtubule attachments, 2) to define kinetochore-independent essential functions of core checkpoint pathway components, and 3) to determine if enhancing cohesion fatigue is a viable strategy to target cancer cell division. These goals will be addressed in 4 specific aims. Aim 1 will focus on understanding the formation of Ndc80-mediated end-coupled attachments, which are accelerated by lateral capture of microtubules by kinetochore-localized dynein, the major minus end-directed microtubule motor in cells. The proposed work will investigate crosstalk we discovered between the kinetochore dynein module and the Ndc80 complex and determine its significance to chromosome segregation fidelity. Aim 2 will address poorly understood essential functions of the conserved Bub1 kinase and the Ndc80 complex subunit Nuf2 in the formation of kinetochore- microtubule attachments. Aim 3 will focus on the provocative idea, based on our recent findings, that there are essential functions of the spindle checkpoint proteins Mad1 and Mad2 independent of their role in kinetochore- based checkpoint signaling. This aim exploits mechanism-based engineering of the Mad1/Mad2 complex in an organismal context to elucidate the basis for the severe developmental and fertility defects associated with loss of Mad1/Mad2 in C. elegans, which we have shown are independent of kinetochore-localization dependent checkpoint signaling. Finally, Aim 4 builds on our observation that sister chromatids of chromosomes attached to the spindle ultimately become unglued in an uncoordinated manner when mitosis is prolonged; this traps the cell in an aberrant state, termed cohesion fatigue, from which it cannot recover. We will broadly assess if the propensity for cohesion fatigue is increased in cancer cell lines, as suggested by preliminary data, and determine whether enhancing cohesion fatigue could serve as a strategy to target cancer cell division.

描述（由申请人提供）：在细胞分裂期间，复制的基因组准确分配到子细胞对于所有活生物体的发育和繁殖至关重要。基因组分布的错误是癌细胞的标志，参与这一过程的机制是癌症化疗的目标。因此，阐明确保准确的基因组分布的机制将为我们了解癌症的起源提供信息，并指导新治疗策略的开发。动粒是基因组分布中的一个主要参与者，它是在有丝分裂期间建立在染色体的着丝粒区域上的机器，用于产生与纺锤体微管的动态末端偶联界面。这个界面的机制与称为纺锤体检查点的信号通路紧密结合，该信号通路阻止细胞周期进展，直到所有染色体连接到纺锤体。微管结合和检查点信号在动粒处由保守的Knl 1/Mis 12复合物/Ndc 80复合物（KMN）蛋白网络协调。在该蛋白质组中，Ndc 80复合物直接与微管末端相互作用。本文提出的工作有三个目标：1）阐明确保Ndc 80介导的着丝粒-微管附着准确形成的机制，2）定义核心检查点通路组分的着丝粒-独立的基本功能，以及3）确定增强内聚疲劳是否是靶向癌细胞分裂的可行策略。这些目标将在四个具体目标中加以解决。目的1将专注于了解Ndc 80介导的末端偶联附件的形成，这是加速微管的横向捕获由kinetochore-localized动力蛋白，主要负端定向微管电机在细胞中。拟议的工作将调查串扰，我们发现之间的动粒动力蛋白模块和Ndc 80复合物，并确定其意义的染色体分离保真度。目的2将解决知之甚少的保守的Bub 1激酶和Ndc 80复合物亚基Nuf 2在形成着丝粒微管附件的基本功能。目的3将集中在挑衅性的想法，根据我们最近的发现，有纺锤体检查点蛋白Mad 1和Mad 2的基本功能，独立于它们在基于动粒的检查点信号传导中的作用。该目标利用生物体背景下Mad 1/Mad 2复合物的基于机制的工程来阐明与C中Mad 1/Mad 2缺失相关的严重发育和生育缺陷的基础。elegans，我们已经表明，这是独立的kinetochore-localization依赖检查点信号。最后，目标4建立在我们的观察基础上，即当有丝分裂延长时，附着在纺锤体上的染色体的姐妹染色单体最终以不协调的方式脱胶;这使细胞陷入异常状态，称为内聚力疲劳，它无法恢复。我们将广泛评估内聚疲劳的倾向是否在癌细胞系中增加，如初步数据所示，并确定增强内聚疲劳是否可以作为靶向癌细胞分裂的策略。