MOLECULAR ANALYSIS OF CYTOKINESIS IN DICTYOSTELIUM

盘基网柄菌细胞分裂的分子分析

• 批准号: 7001341
• 负责人: ARTURO DE LOZANNE
• 金额: $ 32.42万
• 依托单位: UNIVERSITY OF TEXAS AT AUSTIN
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7001341
• 关键词: MOLECULAR; ANALYSIS; CYTOKINESIS; DICTYOSTELIUM

DESCRIPTION (provided by applicant): Despite recent advances, cytokinesis remains the least understood aspect of the cell cycle. In animal cells, cytokinesis requires the coordination of multiple cellular components including the microtubule cytoskeleton, the actin cytoskeleton and membrane traffic. Today, it is not clear how these components are regulated and how they interact with each other. The long-term goal of this project is to define the elements involved in cytokinesis and to understand how these elements integrate to accomplish cytokinesis. Toward that goal, three proteins required for cytokinesis in Dictyostelium have been identified. These three proteins provide a handle on three different pathways that come together during cytokinesis. The objective of this grant is to dissect the contribution of these three pathways during cytokinesis: 1) The role of LvsA in cytokinesis and osmore, qulation will be determined. LvsA is a member of the novel beach family of membrane trafficking proteins and is required for cytokinesis and for the function of the contractile vacuole. This provides the opportunity to dissect the contribution of membrane traffic to cytokinesis in a simple model system. The functional contribution of each of the LvsA domains to its localization and function in vivo will be ascertained. Binding partners for LvsA will be identified and their requirement for cytokinesis will be tested. Genetic suppressors of LvsA will be isolated and the mechanism of suppression will be determined. These studies will illuminate our understanding of membrane processes in cytokinesis and also how mutations in a human homologue of LvsA (LYST) cause a human disorder, the Chediak-Higashi Syndrome. 2) The signaling pathway mediated by RacE and essential for cytokinesis will be delineated. The small GTPase Race is essential for the development of cortical tension and for the ingression of the cleavage furrow. A combination of approaches will be used to dissect the mechanisms by which racE controls cytokinesis and cortical tension. The hypothesis that racE promotes crosslinking of the actin cytoskeleton to enhance cortical tension will be tested. The requirement of cortical tension for the proper ingression of the cleavage furrow will be determined. Binding partners racE will be identified and their role in the development of cortical tension and cytokinesis will be determined. 3) The role of DdlNCENP in cytokinesis will be dissected. INCENP is a microtubule-binding protein known to be important for mitosis & cytokinesis in all organisms but its exact role in cytokinesis has not been identified. Our group has identified the Dictyostelium INCENP homologue and created a DdlNCENP knockout mutant. These tools will be used to explore the relationship of the microtubule cytoskeleton with the organization of the contractile ring during cytokinesis. Since INCENPs are known to be involved in tumorigenesis these results may provide insights into the mechanisms of tumor formation.

描述（由申请人提供）：尽管最近取得了进展，胞质分裂仍然是细胞周期中最不为人所知的方面。在动物细胞中，胞质分裂需要多种细胞成分的协调，包括微管细胞骨架、肌动蛋白细胞骨架和膜运输。目前，尚不清楚这些组件是如何监管的以及它们如何相互作用。该项目的长期目标是定义参与胞质分裂的元素，并了解这些元素如何整合以完成胞质分裂。为了实现这一目标，已鉴定出盘基网柄菌胞质分裂所需的三种蛋白质。这三种蛋白质提供了在胞质分裂过程中聚集的三种不同途径的控制。这笔资助的目的是剖析这三种途径在胞质分裂过程中的贡献： 1)将确定LvsA在胞质分裂和渗透压中的作用。 LvsA 是新型膜运输蛋白 beach 家族的成员，是胞质分裂和收缩液泡功能所必需的。这提供了在简单的模型系统中剖析膜运输对胞质分裂的贡献的机会。将确定每个 LvsA 结构域对其体内定位和功能的功能贡献。将鉴定 LvsA 的结合伴侣并测试它们对胞质分裂的要求。 LvsA 的基因抑制因子将被分离出来并确定抑制机制。这些研究将阐明我们对胞质分裂中膜过程的理解，以及人类 LvsA 同源物 (LYST) 的突变如何导致人类疾病，即 Chediak-Higashi 综合征。 2) 将描述由 RacE 介导且对于胞质分裂至关重要的信号传导途径。小 GTP 酶种族对于皮质张力的发展和乳沟的进入至关重要。将使用多种方法来剖析 racE 控制胞质分裂和皮质张力的机制。 racE 促进肌动蛋白细胞骨架交联以增强皮质张力的假设将得到检验。将确定乳沟沟正确进入的皮质张力要求。将鉴定结合伙伴 racE，并确定其在皮质张力和胞质分裂发展中的作用。 3)将剖析DdlNCENP在胞质分裂中的作用。 INCENP 是一种微管结合蛋白，已知对所有生物体的有丝分裂和胞质分裂都很重要，但其在胞质分裂中的确切作用尚未确定。我们的小组已经鉴定了盘基网柄菌 INCENP 同源物并创建了 DdlNCENP 敲除突变体。这些工具将用于探索胞质分裂过程中微管细胞骨架与收缩环组织的关系。由于已知 INCENP 参与肿瘤发生，这些结果可能为肿瘤形成机制提供见解。