Spatial Regulation of RGS and G Protein Signaling

RGS 和 G 蛋白信号传导的空间调控

• 批准号: 8817041
• 负责人: MARILYN Gist FARQUHAR
• 金额: $ 43.36万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-17 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8817041
• 关键词: 1-Phosphatidylinositol 3-Kinase; Abbreviations; Affect; Affinity; Autophagocytosis; Binding; Binding Proteins; Biogenesis; Biological Assay; CDK5 gene; Cell Proliferation; Cell membrane; Cell physiology; Cells; Clathrin-Coated Vesicles; Co-Immunoprecipitations; Coat Protein Complex I; Cytoplasm; Data; Development; Disease; Dissociation; Dominant-Negative Mutation; EGF gene; Early Endosome; Electron Microscopy; Endocytic Vesicle; Endocytosis; Endoplasmic Reticulum; Endosomes; Epidermal Growth Factor Receptor; Equilibrium; Fluorescence Resonance Energy Transfer; Funding; G Protein-Coupled Receptor Genes; G-Protein-Coupled Receptors; GTP-Binding Protein Regulators; GTP-Binding Protein alpha Subunits, Gs; GTP-Binding Proteins; GTPase-Activating Proteins; Goals; Golgi Apparatus; Grant; Green Fluorescent Proteins; Growth; Growth Factor; Growth Factor Receptors; Guanine; Guanine Nucleotide Dissociation Inhibitors; Guanine Nucleotide Exchange Factors; Guanosine Triphosphate; Hand; Heterotrimeric GTP-Binding Proteins; Immunofluorescence Immunologic; Immunoprecipitation; In Situ; Intracellular Membranes; Ligation; Light; Link; Malignant Neoplasms; Mass Spectrum Analysis; Mediating; Membrane; Mitosis; Modeling; Molecular; Monomeric GTP-Binding Proteins; Neoplasm Metastasis; Normal Cell; Pathway interactions; Phosphorylation; Phosphotransferases; Physiological; Positioning Attribute; Proliferating; Property; Protein Binding; Protein C; Proteins; RGS Proteins; RGS19 gene; Receptor Protein-Tyrosine Kinases; Recycling; Regulation; Relative (related person); Role; Signal Pathway; Signal Transduction; Site; Small Interfering RNA; Testing; Transducers; Transport Vesicles; Vesicle; Vesicle Transport Pathway; Work; anticancer research; antitumor agent; base; cell behavior; cell motility; genetic regulatory protein; inhibitor/antagonist; insight; migration; mutant; new therapeutic target; novel; protein complex; protein function; public health relevance; receptor downregulation; research study; response; secretory protein; tool; trafficking

DESCRIPTION (provided by applicant): Under this grant we have discovered a number of G protein binding proteins, established their properties and revealed new roles for heterotrimeric G proteins in cells. During the current funding period we characterized GIV, a non-receptor GEF that activates G�proteins. GIV serves as a multimodular signal transducer that assembles protein complexes and links G�ubunits to other signaling pathways (growth factor and PI3K/Akt signaling) and to several important cell functions, including cell migration, autophagy, transport of secretory proteins, and endocytosis of growth factor receptors. GIV also binds G� promotes EGF receptor downregulation, and shuts down proliferative signaling from endosomes. The overall goal of the work proposed is to take advantage of the tools and insights we have developed to shed light on some well-known but poorly understood functions of G proteins especially on intracellular membranes. We will focus on two specific aims: Specific Aim #1: To pinpoint the mechanisms by which GIV and its interactions with G�and G�regulate EGFR trafficking and growth factor signaling. Our working model based on preliminary data is that GIV sequentially binds G� and G�after EGF stimulation and that phosphomodification of GIV regulates the relative binding to the two G proteins and determines whether cells migrate or proliferate. Specific Aim #2: To determine the role of G� and GIV in Golgi functions and to define the mechanisms involved. Our data indicate that depletion of GIV or a GIV mutant that fails to activate G� slows transport of newly synthesized proteins through the Golgi. Our working hypothesis based on preliminary data is that GIV does so by activating G�, down-regulating Arf1 activity, and facilitating vesicle uncoating. These studies can be expected to provide novel insights into how GIV binds and regulates two different G proteins and influences growth factor signaling, Golgi functions, cell migration and cell proliferation. Based on its crucil functions in regulating cell behavior, it is essential to define GIV's functions and interactions. Our studies will not only provide insights into fundamental roles of G proteins in cell functions, but also it may establish new paradigms that will help to identify new therapeutic targets for development of pharmacologic and anti-tumor agents. We are uniquely positioned to tackle these problems by taking advantage of the new tools, expertise, and information we have in hand.

描述（由申请人提供）：在这项资助下，我们发现了一些G蛋白结合蛋白，确定了它们的性质，并揭示了异源三聚体G蛋白在细胞中的新作用。在目前的资助期内，我们对GIV进行了表征，这是一种激活G蛋白的非受体GEF。GIV是一种多模块信号传感器，可组装蛋白质复合物，并将G亚单位连接到其他信号通路（生长因子和PI3K/Akt信号通路）和一些重要的细胞功能，包括细胞迁移、自噬、分泌蛋白的运输和生长因子受体的内吞作用。GIV还结合G -促进EGF受体下调，并关闭内体的增殖信号。这项工作的总体目标是利用我们已经开发的工具和见解来阐明一些众所周知但知之甚少的G蛋白功能，特别是在细胞膜上。我们将专注于两个具体目标：具体目标#1：查明GIV及其与G和G相互作用调节EGFR贩运和生长因子信号传导的机制。我们基于初步数据的工作模型是，在EGF刺激后，GIV依次结合G和G，并且GIV的磷酸化调节与两种G蛋白的相对结合，并决定细胞是否迁移或增殖。具体目标#2：确定G和GIV在高尔基函数中的作用，并定义相关机制。我们的数据表明，GIV的耗尽或不能激活G的GIV突变体会减慢新合成蛋白通过高尔基体的运输。我们基于初步数据的工作假设是，GIV通过激活G α，下调Arf1活性，促进囊泡脱膜来实现这一功能。这些研究有望为GIV如何结合和调节两种不同的G蛋白并影响生长因子信号传导、高尔基体功能、细胞迁移和细胞增殖提供新的见解。基于其在调节细胞行为中的关键功能，有必要确定GIV的功能和相互作用。我们的研究不仅将提供G蛋白在细胞功能中的基本作用的见解，而且可能建立新的范式，将有助于确定新的治疗靶点，开发药物和抗肿瘤药物。通过利用我们手中的新工具、专业知识和信息，我们在解决这些问题方面处于独特的地位。