Signalling Processes in Dictyostelium

盘基网柄菌的信号传导过程

基本信息

批准号：
7988495
负责人：
RICHARD A FIRTEL
金额：
$ 9.74万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-12-17 至 2010-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7988495
关键词：
Adaptor Signaling Protein Adhesions Affect Back Biochemical Biochemical Genetics Biological Biological Assay Biological Models Biological Process Cell Adhesion Cell Polarity Cell-Matrix Junction Cells Chemotactic Factors Chemotaxis Complex Cytoskeleton Defect Development Dictyostelium Eukaryotic Cell Evolution Family GTPase-Activating Proteins Goals Guanine Nucleotide Exchange Factors Guanosine Triphosphate Phosphohydrolases Immune system Individual Insertional Mutagenesis Lateral Ligand Binding Ligands Mediating Methods Monomeric GTP-Binding Proteins Movement Natural Immunity Pathway interactions Phosphorylation Phosphotransferases Physiological Play Positioning Attribute Process Protein Phosphatase 2A Regulatory Subunit PR53 Proteins Reaction Regulation Reporter Role Side Signal Pathway Signal Transduction Surface System Time Translating Work base blastomere structure cancer cell cell motility cell type computerized data processing directional cell extracellular human disease insight macrophage man migration myosin heavy-chain kinase A neutrophil null mutation ras GTPase-Activating Proteins ras Guanine Nucleotide Exchange Factors ras Proteins ras-Related G-Proteins response small molecule yeast two hybrid system

项目摘要

DESCRIPTION (provided by applicant): Chemotaxis, or directed cell movement toward a small molecule ligand, plays a key role in many cellular and physiological responses, including metastasis of cancer cells, movement of neutrophils and macrophages in immune system reactions, migration of embryonic cells during development, and aggregation of Dictyostelium during development. In each of these varied cell types and processes, the responding cells are able to amplify a shallow extracellular chemoattractant gradient into a very steep intracellular gradient and thus translate the directional signal into directional cell movement. Fulfillment of this requirement occurs through an integrated circuit of signaling pathways that are highly conserved through evolution between Dictyostelium and man. Recent findings establish that the Ras and the related GTPase Rap1 are important for directional sensing, pseudopod formation, cell polarization, and cell attachment. Both Ras and Rap1 are preferentially activated at the leading edge of chemotaxing Dictyostelium cells and abrogation of their function impairs this process. This proposal focuses on the further examination of the roles of Ras and Rap1 of using Dictyostelium cells, which are amenable to biochemical, genetic, and cell biological approaches. We propose to identify the mechanisms by which the activations of Ras and Rap1 are regulated and spatially restricted to the leading edge of chemotaxing cells. This will be achieved through the analysis of a RasGEF complex and by examining defects in chemotaxis resulting from disruptions of specific GTPase activating proteins (GAPs) for Ras and for Rap1. Through the examination of the spatial and temporal regulation of activated Ras and Rap1 strains in which normal Ras and Rap1 activity is altered, we will elucidate the mechanisms by which cells orient themselves in a chemoattractant gradient. We propose to determine how Ras and Rap1 help mediate chemotaxis through the identification of downstream effectors. The function of these will be examined through the analysis of their null mutations with the aid of real-type fluorescent reporters and biochemical assays that reveal different components of directional sensing, pseudopod formation, and cell polarization. The work proposed in this application should provide new and important insights into mechanisms that control this highly evolutionarily conserved cell biological process, and thus provide the needed background to elucidate the cellular basis underlying a variety of human diseases, including those affecting innate immunity and metastasis of cancer cells.

描述（由申请人提供）：趋化性或向小分子配体的定向细胞运动在许多细胞和生理反应中起着关键作用，包括癌细胞的转移，中性粒细胞和巨噬细胞在免疫系统反应中的运动，在发育过程中胚胎细胞的迁移以及发育过程中的胚胎细胞的迁移。在这些各种细胞类型和过程中，响应细胞能够将浅的细胞外趋化剂梯度扩增到非常陡峭的细胞内梯度中，从而将方向信号转化为方向性的细胞运动。实现这一要求是通过信号通路的集成电路进行的，这些通路通过dictyostelium和han之间的进化而高度保守。最近的发现表明，RA和相关的GTPase RAP1对于定向感测，假脚架形成，细胞极化和细胞附着很重要。 RAS和RAP1都优先在趋化dictyostelium细胞的前缘激活，并废除其功能会损害此过程。该建议着重于对使用Dictyostelium细胞的Ras和Rap1的作用的进一步研究，这些细胞可与生化，遗传和细胞生物学方法相提并论。我们建议确定RAS和RAP1的激活受到调节并在空间上限制为化学轴向轴的前缘的机制。这将通过分析RASGEF复合物，并通过检查因RAS和RAP1的特定GTPase激活蛋白（GAP）而导致的趋化性缺陷来实现。通过检查正常RAS和RAP1活性的活化Ras和RAP1菌株的空间和时间调节，我们将阐明细胞以趋化吸引梯度定向的机制。我们建议通过鉴定下游效应子来确定RAS和RAP1如何帮助介导趋化性。这些功能将通过借助实型荧光报告基因和生化测定法对其无效突变进行研究，从而揭示了定向感测，假脚架形成和细胞极化的不同组成部分。本应用中提出的工作应提供有关控制这种高度进化保守的细胞生物学过程的机制的新的重要见解，从而提供了所需的背景，以阐明各种人类疾病的细胞基础，包括影响先天免疫和癌细胞转移的细胞。