Regulation of Microtubules by Rho GTPases

Rho GTPases 对微管的调节

• 批准号: 7152542
• 负责人: Gregg G Gundersen
• 金额: $ 35.4万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7152542
• 关键词: Actins; Adenomatous Polyposis Coli Protein; Affect; Behavior; Binding; Biochemical; Biological; Biological Models; COX7A2L Protein; Cell Nucleus; Cell Polarity; Cells; Characteristics; Complex; Cytoskeleton; DNA Sequence Rearrangement; Development; Dynein ATPase; Eukaryotic Cell; Event; Family; Fibroblasts; Genetic; Goals; Grant; Guanosine Triphosphate Phosphohydrolases; In Vitro; Kinesin; Lysophospholipids; Maintenance; Mammalian Cell; Mediating; Microtubule Stabilization; Microtubule-Organizing Center; Microtubules; Monomeric GTP-Binding Proteins; Motor; Movement; Myosin ATPase; Myosin Type II; Neoplasm Metastasis; Pathway interactions; Phosphorylation; Phosphotransferases; Plus End of the Microtubule; Polymers; Positioning Attribute; Process; Proteins; Regulation; Rewards; Serum; Signal Pathway; Signal Transduction; System; Testing; Thinking; Work; Wound Healing; Yeasts; actin kinase; cell associated matrix; cell cortex; cell motility; cellular transduction; dynactin; lysophosphatidic acid; monolayer; mutant; novel; response; rho; rho GTP-Binding Proteins; wound

DESCRIPTION (provided by applicant): The overall goal of this project is to understand how small GTPases of the Rho family regulate the stability and organization of microtubules (MTs) during cell polarization. The dynamics of MTs gives them the ability to response to external signals during cell polarization, yet little is known about how these signals are transduced to MTs or the proteins that are involved in MT rearrangements. Cells migration into an in vitro wound is a model system for studying the signals regulating MT as the contribution of soluble, matrix and cell-associated factors can be dissected. In the previous grant period, we found that the two rearrangements of MTs in wound edge migrating fibroblasts, formation of a subset of unusually stable MTs and reorientation of the MT organizing center (MTOC), are both triggered by serum lysophosphatidic acid (LPA), but are separately regulated by Rho and Cdc42 GTPases. Both of these rearrangements are thought to involve interactions of MT ends with the cell cortex, a process termed MT capture. We identified mDia, EB1, APC, GSK3beta and novel PKCs as factors working downstream of Rho and two separate pathways working downstream of Cdc42; one involving Par6, dynein and dynactin maintenance of the MTOC at the cell center, the other involving MRCK, actin and myosin II functioning in a novel reward movement of the nucleus. The current aims are to further explore the mechanism of MT stabilization by: exploring how mDia's activity toward MTs and actin is apportioned, by testing whether mDia can directly affect MT stabilization and whether EB1 and APC may affect mDia's activity toward MTs. We will also test whether complexes between mDia, EB1 and APC are regulated by GSK3beta and and screen for additional proteins that may contribute to MT stabilization. The mechanism of Par6, dynein and dynactin regulated MTOC centration will be explored by determining how Par 6 regulates dynein and dynactin, whether additional proteins regulate dynein and dynactin and whether dynein and dynactin maintain the MTOC at the cell center by cortical MT capture. Understanding how Rho GTPases and the pathways they stimulate act to regulate MTs will provide new information about the fundamental ways cells transduce signals to control cytoskeletal systems during cell migration, a process of importance for development, wound healing and metastasis.

描述(由申请人提供)：本项目的总体目标是了解Rho家族的小GTP酶如何在细胞极化过程中调节微管(MT)的稳定性和组织。MTS的动力学使它们能够在细胞极化过程中对外部信号做出反应，但这些信号是如何传递到MTS或参与MT重排的蛋白质的，人们知之甚少。细胞迁移到体外创面是研究MT信号调控的一个模型系统，因为可以剖析可溶性、基质和细胞相关因素的贡献。在之前的研究中，我们发现创伤边缘移行成纤维细胞中MT的两次重排，即形成异常稳定的MT亚群和MT组织中心(MTOC)的重新定位，都是由血清溶血磷脂酸(LPA)触发的，但分别受Rho和CDC42 GTP酶的调控。这两种重排都被认为涉及MT末端与细胞皮质的相互作用，这一过程被称为MT捕获。我们确定MDIA、EB1、APC、GSK3β和新型PKCs是Rho下游的作用因子，以及在CDC42下游作用的两条独立的通路：一条涉及细胞中心MTOC的Par6、dynein和dynactin维持，另一条涉及MRCK、肌动蛋白和肌球蛋白II在细胞核的一种新的奖赏运动中发挥作用。目前的研究目的是通过检测MDIA是否能直接影响MT的稳定性，以及EB1和APC是否能影响MDIA对MTS的活性，从而进一步探讨MT的稳定机制。我们还将测试MDIA、EB1和APC之间的复合体是否受GSK3β和GSK3β的调节，并筛选可能有助于MT稳定的其他蛋白质。PAR6、dynein和dynactin调节MTOC浓度的机制将通过确定PAR 6如何调节dynein和dynactin，是否有额外的蛋白质调节dynein和dynactin，以及dynein和dynactin是否通过捕捉皮质MT而维持在细胞中心的MTOC来探讨。了解Rho GTP酶及其刺激的途径如何调节MTS，将为细胞在细胞迁移过程中传递信号以控制细胞骨架系统提供新的信息，这是一个对发育、伤口愈合和转移至关重要的过程。