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.

项目总结/文摘