Spatial Regulation of Cytoskeleton During Chemotaxis

描述（由申请人提供）：许多真核细胞经历趋化性，朝向可溶性配体定向运动。这一过程是许多生物功能所必需的，包括伤口愈合、轴突导向和网骨细胞的聚集。趋化性也在疾病状态中发挥作用，如关节炎、癌症和多发性硬化症。定向细胞运动需要确定的细胞极性，其中细胞骨架的组成部分差异地定位在迁移细胞的前缘及其收缩的后部。这种极化可以通过异源三聚体G蛋白偶联的膜结合受体的化学引诱物结合来引发，并且随后下游信号转导途径的激活直接肌动蛋白和肌球蛋白细胞骨架的重组。我们以前的研究表明，一个极化的肌动蛋白细胞骨架是通过集中在细胞皮层的肌动蛋白组装的调节剂，如WASP和Escherin亚结构域。本研究的目的是了解在趋化过程中WASP的亚细胞定位和激活是如何调节的。我们推测，PCH家族蛋白，CLP 1/2，和RacC之间的复杂的相互作用，导致WASP和ACA的极化贩运，导致细胞极性的建立通过肌动蛋白细胞骨架的极化组织和ACA的不对称分布在网骨藻趋化性。为了验证这一假设，我们提出了以下具体目标：1）阐明PCH家族蛋白，CLP 1/2和RacC在控制囊泡形成过程中WASP的功能和定位中的作用。2)研究CLP 1/2、RacC和Unc 104在WASP-和ACA-囊泡运输中的作用。3)研究WASP-和ACA-囊泡的极化运输如何有助于在趋化过程中建立细胞极性。预计这些研究将不仅提供新的见解如何从高尔基体的胞吐囊泡形成的控制，但也了解细胞极性可以实现B囊泡运输过程中趋化。 公共卫生相关性：我们体内的许多细胞都经历趋化性，定向运动到一种化合物，这是许多生物功能所必需的，包括伤口愈合和神经系统的发育。趋化性也在疾病状态中发挥作用，如关节炎、癌症和多发性硬化症。我们提出的研究将帮助我们了解细胞如何保持细胞极性和定向细胞运动时，他们朝着一个方向性的线索定向迁移。

DESCRIPTION (provided by applicant): Many eukaryotic cells undergo chemotaxis, directed movement towards a soluble ligand. This process is necessary for many biological functions, including wound healing, axonal guidance, and the aggregation of Dictyostelium cells. Chemotaxis also plays a role in disease states such as arthritis, cancer, and multiple sclerosis. Directional cell movement requires a defined cell polarity in which components of the cytoskeleton are differentially localized at the leading edge of a migrating cell as well as its retracting posterior. This polarization can be initiated by the chemoattractant binding of heterotrimeric G protein-coupled membrane- bound receptors, and subsequent activation of downstream signal transduction pathways direct reorganization of the actin and myosin cytoskeleton. Our previous studies suggested that a polarized actin cytoskeleton is achieved by concentrating regulators of actin assembly such as WASP and WIP in subdomains at the cell cortex. The goal of this study is to understand how the subcellular localization and activation of WASP is regulated during chemotaxis. We hypothesize that a complex interplay between PCH family proteins, CLP1/2, and RacC leads to polarized trafficking of WASP and ACA, resulting in cell polarity establishment via the polarized organization of actin cytoskeleton and asymmetric distribution of ACA during Dictyostelium chemotaxis. To test this hypothesis, we propose the following specific aims: 1) To elucidate the role of PCH family proteins, CLP1/2 and RacC in controlling function and localization of WASP during vesicle formation. 2) To investigate roles of CLP1/2, RacC, and Unc104 in the trafficking of WASP- and ACA-vesicles. 3) To study how polarized trafficking of WASP- and ACA-vesicles contribute to establish cell polarity during chemotaxis. It is anticipated that these studies will serve not only to provide new insights on how exocytic vesicle formation from Golgi is controlled, but also to understand how cellular polarity can be achieved b vesicle trafficking during chemotaxis. PUBLIC HEALTH RELEVANCE: Many cells in our body undergo chemotaxis, directed movement toward a chemical compound which is necessary for many biological functions including wound healing and the development of the nervous system. Chemotaxis also plays a role in disease states such as arthritis, cancer, and multiple sclerosis. Our proposed research would help us understand how cells maintain cell polarity and directed cell movement when they migrate directionally toward a directional cue.