Gamma-Tubulin And Centrosome Structure And Function

γ-微管蛋白和中心体的结构和功能

• 批准号: 6519620
• 负责人: Tim Stearns
• 金额: $ 27.48万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6519620
• 关键词: Schizosaccharomyces pombe; Xenopus; binding proteins; cell cycle; centrosome; electron microscopy; gene mutation; human tissue; immunofluorescence technique; immunoprecipitation; laboratory rabbit; microtubules; molecular cloning; phenotype; polymerase chain reaction; protein biosynthesis; protein protein interaction; protein structure function; stoichiometry; tissue /cell culture; tubulin; western blottings

DESCRIPTION (Verbatim from the applicant's abstract): The long term objective of this proposal is to understand the molecular basis of microtubule organizing center function, which is essential to generating a polar microtubule cytoskeleton to carry out the important tasks of chromosome segregation, cell motility, organelle transport, and nuclear migration. We have only just begun to answer some of the central questions in this field: How does the organizing center nucleate the growth of microtubules? How is nucleation temporally and spatially regulated? Which molecules are important for which functions in the organizing center? Cancer cells often have defects in microtubule organizing center size and number, possibly leading to genetic instability, demonstrating the importance of these questions. To further our understanding of the microtubule organizing center (called the centrosome in animal cells) I will focus primarily on the structure and function of gamma-tubulin and the large macromolecular assembly of which it is part, gamma-tubulin complex (also called the gamma-tubulin ring complex, or gamma-TuRC). The gamma-tubulin complex is required for microtubule nucleation, and has been proposed to act as a direct template for the polymerization of microtubules. The gamma-tubulin complex is made up of gamma-tubulin plus five different polypeptides. This remarkable complex must interact both with microtubules and the centrosome, placing it at the center of microtubule organization. We have found that all five of the gamma-tubulin complex proteins, or GCPs, belong to a new protein superfamily. The importance of gamma-tubulin in microtubule organization has led us to search for new tubulins in the mammalian genome and we have discovered two, d(delta)-tubulin and e(epsilon)-tubulin. Epsilon tubulin has not been described before in any organism, and its properties suggest a role in centrosome function as well. We will attack four specific aims in the next project period: 1) Determine the subunit composition and structure of the gamma-tubulin complex. 2) Define the interactions among the gamma-tubulin complex proteins, and their role in the gamma-tubulin complex. 3) Characterize the interaction of the gamma-tubulin complex with the microtubule and the centrosome. 4) Characterize the role of epsilon-tubulin in centrosome function.

描述（申请人摘要的逐字记录）：长期目标 该提案的目的是了解微管组织的分子基础 中心功能，对于生成极性微管至关重要 细胞骨架执行染色体分离的重要任务，细胞 运动、细胞器运输和核迁移。我们才刚刚开始 回答该领域的一些核心问题：如何组织 中心成核微管的生长？成核是如何暂时发生的 空间调节？哪些分子对哪些功能很重要 组织中心？癌细胞的微管组织通常存在缺陷 中心大小和数量，可能导致遗传不稳定，证明 这些问题的重要性。为了加深我们对 微管组织中心（动物细胞中称为中心体）我会 主要关注γ-微管蛋白和大分子的结构和功能 它是大分子组装体的一部分，γ-微管蛋白复合物（也称为 γ-微管蛋白环复合物，或γ-TuRC）。 γ-微管蛋白复合物是 微管成核所需的，并已被提议作为直接 微管聚合的模板。 γ-微管蛋白复合物是 由 γ-微管蛋白加上五种不同的多肽组成。这个非凡的 复合体必须与微管和中心体相互作用，将其置于 微管组织的中心。我们发现所有五个 γ-微管蛋白复合蛋白（GCP）属于一个新的蛋白质超家族。 γ-微管蛋白在微管组织中的重要性使我们 在哺乳动物基因组中寻找新的微管蛋白，我们发现了两种， d(δ)-微管蛋白和e(ε)-微管蛋白。 Epsilon微管蛋白尚未被描述 之前存在于任何生物体中，其特性表明在中心体中发挥作用 功能也一样。我们将在下一个项目期间实现四个具体目标： 1) 确定γ-微管蛋白的亚基组成和结构 复杂的。 2) 定义γ-微管蛋白复合体蛋白之间的相互作用， 以及它们在γ-微管蛋白复合物中的作用。 3）表征相互作用 γ-微管蛋白与微管和中心体的复合物。 4） 描述ε-微管蛋白在中心体功能中的作用。