GBeta5/RGS proteins and GPCR signaling

Gbeta5/RGS 蛋白和 GPCR 信号传导

• 批准号: 7904747
• 负责人: JOHN E SONDEK
• 金额: $ 27.46万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7904747
• 关键词: Activities of Daily Living; Binding; Binding Proteins; Biochemical; Boxing; Complement; Complex; Crystallography; Data; Event; Exhibits; Free Will; G Protein-Coupled Receptor Signaling; G-Protein-Coupled Receptors; GTP Binding; GTP-Binding Protein Regulators; GTP-Binding Proteins; GTPase-Activating Proteins; Guanine Nucleotides; Guanosine Triphosphate Phosphohydrolases; Heterotrimeric G Protein Subunit; Heterotrimeric GTP-Binding Proteins; Length; Lobe; Mediating; Membrane; Molecular Models; N-terminal; Physiological; Protein Subunits; Proteins; RGS Domain; RGS Proteins; RGS9 protein; Research; Research Personnel; Role; Signal Pathway; Signal Transduction; Signaling Protein; Specificity; Structure; Surface; System; Testing; Treatment Protocols; Work; base; design; dimer; empowered; molecular modeling; novel; programs; protein complex; reconstitution

DESCRIPTION (provided by applicant): The Regulator of G protein Signaling (RGS) proteins originally were identified as GTPase-activating proteins (GAPs) for heterotrimeric G protein ? subunits. However, many RGS proteins possess highly- conserved domains in addition to the signature RGS box, which empower a multifunctional character that underlies poorly understood but physiologically important interactions among components of heterotrimeric G protein signaling cascades as well as with other signaling pathways. The R7 subfamily of RGS proteins possess a distinctive G-?-like (GGL) domain that mediates specific and obligate heterodimer formation with the atypical G protein subunit, G?5, suggesting that these signaling proteins exhibit functions similar to conventional G?? dimers. Our recently refined crystal structure of G?5/RGS9 support this idea and provides a framework for testing hypotheses related to various binding interfaces of this dimer that likely subserve the organization and integration of higher-order, multifunctional G protein/GPCR/RGS complexes. Consequently, we propose to: 1) use crystallography and mutational analyses to define the complete functionality and G? specificity of RGS domains within full-length G??5/R7 dimers; 2) extend our understanding of the functional and structural relationships between G??5/R7 dimers and their anchoring proteins, R9AP and R7BP; and 3) quantify the functional capacities of G??5/R7 dimers to interact with GDP- G? subunits and GPCRs using reconstituted systems of purified components. While it is clear that R7 proteins are required for proper signaling mediated by G protein-coupled receptors under a variety of physiological settings, the roles of these proteins in coordinating these signaling events are relatively poorly understood. The work proposed here is designed to place R7 proteins within a detailed structural and functional context with respect to G protein-coupled receptors and heterotrimeric G proteins. It is anticipated that these studies will then be used to guide treatment regimens in cases where coordinated signaling mediated by R7 proteins has failed.

描述（由申请人提供）： G 蛋白信号调节蛋白（RGS）最初被鉴定为异源三聚体 G 蛋白的 GTP 酶激活蛋白（GAP）？亚单位。然而，许多 RGS 蛋白除了特征性的 RGS 盒外还具有高度保守的结构域，这些结构域赋予了多功能特征，该特征是异源三聚体 G 蛋白信号级联成分之间以及与其他信号传导途径之间的相互作用的基础，但在生理学上知之甚少。 RGS 蛋白的 R7 亚家族具有独特的 G-β 样 (GGL) 结构域，可介导与非典型 G 蛋白亚基 Gβ5 形成特异性和专性异二聚体，表明这些信号蛋白表现出与常规 Gβ 相似的功能。二聚体。我们最近精制的 G?5/RGS9 晶体结构支持了这一想法，并提供了一个框架来测试与该二聚体的各种结合界面相关的假设，这些结合界面可能有助于高级、多功能 G 蛋白/GPCR/RGS 复合物的组织和整合。因此，我们建议：1）使用晶体学和突变分析来定义完整的功能和G？全长 G??5/R7 二聚体中 RGS 结构域的特异性； 2）扩展我们对G??5/R7二聚体及其锚定蛋白R9AP和R7BP之间功能和结构关系的理解； 3) 量化 G??5/R7 二聚体与 GDP-G? 相互作用的功能能力？使用纯化组分的重构系统来构建亚基和 GPCR。虽然很明显，在各种生理环境下，R7 蛋白是 G 蛋白偶联受体介导的正确信号传导所必需的，但人们对这些蛋白在协调这些信号传导事件中的作用相对知之甚少。这里提出的工作旨在将 R7 蛋白置于 G 蛋白偶联受体和异三聚体 G 蛋白的详细结构和功能背景中。预计这些研究将用于在 R7 蛋白介导的协调信号传导失败的情况下指导治疗方案。