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，复制基因组对子细胞的准确分配对于所有生物体的发展和传播至关重要。基因组分布的误差是癌细胞的标志，并且参与此过程的机械针对癌症化疗。因此，阐明确保准确的基因组分布的机制将为我们理解癌症的起源并指导新的治疗策略的发展。基因组分布的主要参与者是Kinetochore，这是有丝分裂过程中染色体的丝粒区域建造的机器，以生成动态的端耦合界面与纺锤微管。该界面上的力学与信号通路紧密整合，称为主轴检查点，该检查点阻止了细胞周期的进程，直到所有染色体都连接到纺锤体。微管结合和检查点信号传导通过保守的KNL1/MIS12复合物/NDC80复合物（KMN）蛋白网络在动力学上协调。在该蛋白质集中，NDC80复合物直接与微管末端相互作用。这里提出的工作有三个目标：1）阐明机制，以确保NDC80介导的介导的动物学微动物附件的准确形成，2）定义核心检查点途径组件的无独立的基本功能，并确定增强凝聚力疲劳的作用，以确定对目标型细胞策略。这些目标将以4个具体目标来解决。 AIM 1将集中于理解NDC80介导的端耦合附件的形成，这些附着的附件是通过动力学量化的动力蛋白侧面捕获微管的横向捕获，这是细胞中主要负端导向的微管运动。拟议的工作将研究我们在Kinetochore Dynein模块和NDC80复合物之间发现的串扰，并确定其对染色体隔离忠诚度的重要性。 AIM 2将解决保守的BUB1激酶和NDC80复合体NUF2的基本功能，在动型微管附着的形成中。 AIM 3将基于我们最近的发现，将重点放在挑衅性的想法上，即主轴检查点蛋白MAD1和MAD2具有独立于基于Kinetochore-基于Kinetochore的检查点信号传导的基本功能。该目标利用了在生物环境中基于机制的MAD1/MAD2复合物的基于机制的工程，以阐明与秀丽隐杆线虫中与MAD1/MAD2丢失相关的严重发育和生育缺陷的基础，我们已经表明，这与动力学 - 位置依赖性依赖性检查点信号传导。最后，AIM 4基于我们的观察，即延长有丝分裂时，附着在纺锤体上的染色体姐妹最终以不协调的方式变得不粘结。这将细胞捕获在异常状态，称为内聚力疲劳，无法从中恢复。如初步数据所示，我们将广泛评估癌细胞系中凝聚疲劳的倾向是否增加，并确定增强凝聚力疲劳是否可以作为靶向癌细胞分裂的策略。