Mechanisms controlling the inactivation of microtubule organizing center function at the centrosome

控制中心体微管组织中心功能失活的机制

• 批准号: 10227900
• 负责人: Jessica Lynn Feldman
• 金额: $ 31.54万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10227900
• 关键词: Adult; Aging; Alleles; Animal Model; Animals; Behavior; Biology; Caenorhabditis elegans; Carcinoma; Catalytic Domain; Cell Cycle; Cell Differentiation process; Cell physiology; Cells; Cellular biology; Centrioles; Centrosome; Chemicals; Cilia; Data; Development; Developmental Biology; Dissection; Embryo; Excision; Genetic; Gonadal structure; Hyperactivity; Image; Intestines; Knowledge; Light; Link; Malignant Neoplasms; Mammary Neoplasms; Mechanics; Mediating; Metaphase; Microtubule-Organizing Center; Microtubules; Mitosis; Mitotic; Mitotic spindle; Modeling; Nature; Organism; Pharmacology; Phosphoric Monoester Hydrolases; Phosphotransferases; Population; Process; Protein Phosphatase 2A Regulatory Subunit PR53; Proteins; Proteomics; RNA Interference; Research; Role; Rupture; Site; Testing; Work; base; cell behavior; in vivo; inhibitor/antagonist; kinetosome; neoplastic cell; new therapeutic target; programs; protein protein interaction; recruit; therapeutic target; time use; tool

Project Summary/Abstract The centrosome acts as a microtubule organizing center (MTOC), orchestrating microtubules into the mitotic spindle through its pericentriolar material (PCM). This activity is biphasic, cycling through assembly and disassembly during the cell cycle. Upon cell differentiation, MTOC activity at the centrosome is often maintained in an inactive state as MTOC function is reassigned to non-centrosomal sites to accommodate different cell functions. Although hyperactive centrosomal MTOC activity is a hallmark of some cancers and has been linked to invasive cell behavior, little is known about how the centrosome is inactivated as an MTOC either during mitotic exit or maintained in an inactive state in differentiated cells. We are using C. elegans as a model to understand these fundamental knowledge gaps in MTOC biology in a live organism. Our analysis of endogenous PCM proteins in C. elegans revealed that the PCM is composed of distinct protein territories organized into an inner and outer sphere that are removed from the centrosome at different rates and using different behaviors. We found that phosphatases oppose the addition of PCM by mitotic kinases, ultimately catalyzing the dissolution of inner sphere PCM proteins at the end of mitosis. The nature of the PCM appears to change such that the remaining aging PCM outer sphere is ruptured into sub-PCM ‘packets’ by microtubule based cortical pulling forces. Thus, the centrosome appears to be inactivated as an MTOC by a two-step mechanism beginning with PCM dissolution, followed by mechanically controlled rupture. In the proposed research, we will uncover the mechanisms underlying this two-step model for the inactivation of MTOC function at the centrosome. We will determine the mechanisms underlying PCM dissolution, identifying the pertinent phosphatases, their targets at the centrosome, and the role of the removal of these targets in disassembly (Aim 1). We will then specifically uncover the protein-protein interactions underlying the PCM outer sphere and packets (Aim 2). Finally, we will probe the mechanisms underlying the inactivation of MTOC function in differentiated cells and test the role of centrosome inactivation in cell differentiation (Aim 3). Proper microtubule organization is essential for normal development and cell function and hyperactive MTOC function at the centrosome is a hallmark of some cancers. Thus, the molecules uncovered in these studies could provide potential therapeutic targets as well as shed light on this important, but understudied topic in cell and developmental biology.

项目摘要/摘要 中心体充当微管组织中心（MTOC），将微管编排到有丝分裂中 通过其周围三元素材料（PCM）主轴。该活动是双相的，通过组装骑自行车 在细胞周期中拆卸。细胞分化后，中心体的MTOC活性通常是 将MTOC函数重新分配到非中心位点以容纳以适应不活跃状态 尽管多动性中心体MTOC活性是某些癌症的标志，虽然各种细胞功能。 与侵入性细胞行为有关，对中心体是如何灭活为MTOC的知之甚少 在有丝分裂出口期间，要么在分化细胞中保持不活跃状态。我们正在使用秀丽隐杆线虫作为 了解活有机体中MTOC生物学中这些基本知识差距的模型。我们的分析 秀丽隐杆线虫中的内源性PCM蛋白显示，PCM由不同的蛋白质领土组成 组织成一个内部和外部球体，这些球体以不同的速度从中心体中移出并使用 不同的行为。我们发现，磷酸酶反对通过有丝分裂激酶添加PCM，最终 在有丝分裂结束时催化内部球体PCM蛋白的溶解。 PCM的性质出现 更改以使剩余的老化PCM外球被微管破裂成子PCM“数据包” 基于皮质拉力。这，中心体似乎被两步灭活为MTOC 机理从PCM溶解开始，然后是机械控制的破裂。在提议中 研究，我们将揭示这一两步模型的MTOC功能模型的机制 在中心体。我们将确定PCM溶解的基础机制，确定相关的 磷酸酶，它们在中心体的靶标，以及去除这些靶标在拆卸中的作用 （目标1）。然后，我们将专门发现PCM外球和PCM外球和 数据包（AIM 2）。最后，我们将探测MTOC函数失活的机制 分化细胞并测试中心体灭活在细胞分化中的作用（AIM 3）。适当的微管 组织对于正常发育和细胞功能以及在 中心体是一些癌症的标志。这是这些研究中发现的分子可以提供的 潜在的治疗靶点以及阐明了这一重要的，但在细胞和 发展生物学。