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Molecular Mechanisms of Mitotic Regulation

有丝分裂调节的分子机制

基本信息

批准号：
9246674
负责人：
P. TODD STUKENBERG
金额：
$ 45.56万
依托单位：
UNIVERSITY OF VIRGINIA
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-19 至 2021-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9246674
关键词：
Anaphase Area Binding Binding Proteins Binding Sites Biochemistry Cell division Cellular Structures Cellular biology Chromosomal Instability Chromosome Segregation Chromosomes Complex Coupling Development Dimensions Drug Targeting Ensure Event Family Foundations Genome Gout Human Image Imagery In Vitro Kinetochores Location Malignant Neoplasms Maps Mediator of activation protein Microscope Microscopy Microtubule Depolymerization Microtubules Mitosis Mitotic Mitotic spindle Modeling Molecular Molecular Models N-terminal Names Organism Pharmaceutical Preparations Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Plus End of the Microtubule Process Prometaphase Protein Dephosphorylation Protein phosphatase Proteins RPS27 gene Recruitment Activity Regulation Resolution Role Signal Transduction Site Source Structure Tail Testing Therapeutic Tomogram Vinca Alkaloids Work aurora B kinase aurora kinase calponin cancer cell chromosome movement foot improved insight molecular modeling mutant new therapeutic target novel prevent segregation single molecule stoichiometry taxane tomography

项目摘要

Equal segregation of the replicated genome during cell division is essential for the development and propagation of all living organisms. Errors in mitotic processes are a hallmark of cancer cells and major chemotherapeutics target the mitotic spindle. One critical function of the kinetochore is to generate the spindle checkpoint signal until each kinetochore has properly attached to microtubules. This signal is initiated by the localization of the MPS1 protein to the calponin homology domain of the Ndc80 complex, which is regulated by Aurora B. However, this domain of Ndc80 protrudes on a long coiled coil far from Aurora kinase, making it unclear how it could be phosphorylated. We have employed a vastly improved super-resolution microscope to visualize human kinetochores. This microscopes unique ability to provide super-resolution in the Z-plane is essential for the study of cellular structure the size of a kinetochore. This visualization of single molecules of Ndc80 in unattached kinetochores has identified a novel pool of the MPS1 binding region of the Ndc80 complex in the central region of spindle checkpoint signaling kinetochores. We hypothesize that this internal pool is a more efficient generator of the spindle checkpoint than the previously appreciated outer pools. We are employing super-resolution microscopy to both test this hypothesis and further map the sub-kinetochore location of key events in generating the spindle checkpoint signals. We will also identify how the spindle checkpoint is turned off by when kinetochores attach to microtubules. We are building upon two important new discoveries about the Ska complex. First, we have identified the steps that enable Ska to be recruited to kinetochores after microtubule attachments. Second, we have shown that Ska binds PP1 providing a mechanism to specifically recruit a phosphatase to properly attached kinetochores. Building upon this strong foundation we will determine how the Ndc80, Ska and PP1 proteins turn off the spindle checkpoint and generate the kinetochore microtubule attachment that allows kinetochores to remain bound to depolymerizing microtubules to move chromosomes.

细胞分裂过程中复制基因组的平等分离对于细胞分裂至关重要所有生物体的发育和繁殖。有丝分裂过程中的错误是癌细胞和主要化疗药物的标志是针对有丝分裂纺锤体。一着丝粒的关键功能是生成纺锤体检查点信号，直到每个动粒已正确附着在微管上。该信号由 MPS1 蛋白定位于 Ndc80 复合物的钙调蛋白同源结构域，其受 Aurora B 调控。然而，Ndc80 的该结构域突出于长 coiled coil far from Aurora kinase, making it unclear how it could be phosphorylated.我们采用了大幅改进的超分辨率显微镜来可视化人类动粒。该显微镜具有在 Z 平面提供超分辨率的独特能力对于研究动粒大小的细胞结构至关重要。这个可视化独立着丝粒中 Ndc80 单分子的研究已经确定了一个新的库纺锤体中央区域 Ndc80 复合物的 MPS1 结合区域检查点信号动粒。我们假设这个内部池是一个更比以前赞赏的外部池更高效的主轴检查点生成器。我们正在采用超分辨率显微镜来检验这一假设并进一步验证在生成纺锤体检查点时映射关键事件的子动粒位置信号。我们还将确定主轴检查点如何在何时关闭着丝粒附着在微管上。我们正在以两项重要的新举措为基础关于斯卡复合体的发现。首先，我们确定了启用 Ska 的步骤微管附着后被募集至动粒。其次，我们已经展示了 Ska 结合 PP1 提供了一种机制来特异性招募磷酸酶正确附着的动粒。在此坚实的基础上，我们将确定 Ndc80、Ska 和 PP1 蛋白如何关闭纺锤体检查点并生成动粒微管附着，允许动粒保持结合解聚微管以移动染色体。