Role of Ubiquitin in Cardiovascular System

泛素在心血管系统中的作用

• 批准号: 7256969
• 负责人: YONG TAE KWON
• 金额: $ 35.08万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-15 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7256969
• 关键词: Address; Affinity; Arginine; Aspartate; Binding; Blood Vessels; Boxing; Cardiac; Cardiac Myocytes; Cardiovascular system; Cell Proliferation; Cells; Congenital Heart Defects; Cultured Cells; Cysteine; Defect; Embryo; Embryonic Heart; Figs - dietary; G Protein-Coupled Receptor Signaling; G-Protein Signaling Pathway; G-Protein-Coupled Receptors; G-substrate; GTP-Binding Protein alpha Subunits, Gs; GTP-Binding Proteins; GTPase-Activating Proteins; Gases; Genes; Glutamates; Goals; Growth; Half-Life; Heart; Homeostasis; In Vitro; Individual; Knock-out; Mediating; Molecular; Myocardial; N-terminal; Names; Nature; Oxygen; Pathway interactions; Physiological; Protein Family; Protein Isoforms; Proteins; Proteolysis; Proteomics; RGS Proteins; Role; Screening procedure; Signal Transduction; Specificity; Testing; Transferase; Ubiquitin; Ventricular; Ventricular Septal Defects; angiogenesis; base; cofactor; in vivo; inhibitor/antagonist; insight; novel; small molecule; tRNA-arginine complex; ubiquitin ligase

DESCRIPTION (provided by applicant): The N-end rule pathway is one ubiquitin (Ub) proteolytic pathway that relates the in vivo half-life of a protein to the identity of its N terminal residue. Conjugation of arginine (Arg) from Arg-tRNA(Arg) to N-terminal aspartate (Asp), glutamate (Glu), or cysteine (Cys) is part of this proteolytic pathway in that it leads to ubiquitylation of the resulting, Arg-conjugated proteins. We previously observed that ATE1-/- embryos die due to various cardiovascular defects. However, the exact nature of the cardiovascular defects and the underlying molecular mechanisms are unknown. The overall goal of this project is to determine the physiological role of ATE1-dependent arginylation in the myocardial growth and to gain insights into the cardiovascular pathways/molecules in which the ATE1-dependent proteolytic pathway participates. Functional proteomic approach to identify the substrates of the N-end rule pathway and subsequent preliminary characterization of the selected candidate substrates led to the hypothesis that RGS4, RGS5, and RGS16 are ATE1 substrates that may underlie the ATE1-dependent cardiovascular system. RGS proteins are GTPase-activating proteins (GAP) for G(alpha) subunits and negatively regulate the G protein- coupled receptor (GPCR) signaling. RGS4, RGS5, and/or RGS16 have been implicated as important negative regulators of the Gq/Gi-activated signaling for myocardial growth and vascular maturation/integrity. We then asked the mechanism by which these RGS proteins are ubiquitylated for proteolysis by ubiquitin ligases (E3s). Using an affinity-based proteomic approach, we identified a novel protein family, named UBR1-UBR7, that potentially acts for ubiquitylation of RGS4, RGS5, and RGS16. Our overall hypothesis is that the cellular concentrations of RGS4, RGS5, and RGS16, and thus their functions as regulators of the cardiovascular G protein pathways, are regulated through the MetAPs-O2-ATE1-UBR proteolytic cascade. To address this hypothesis and related issues, we propose the following Aims. Aim 1: To test whether ATE1 has an in vivo role in intrinsic myocardial growth. Aim 2: To determine the role of ATE 1-dependent arginylation for turnover of RGS4, RGS5, and RGS16. Aim 3: To elucidate the molecular mechanism by which RGS4, RGS5, and RGS16 are ubiquitylated for proteolysis. Aim 4: To examine the physiological consequences of ATE1 knockout on the G protein pathways.

描述（由申请人提供）：N端规则途径是一种泛素（Ub）蛋白水解途径，它将蛋白质的体内半衰期与其N端残基的身份相关联。精氨酸 (Arg) 从 Arg-tRNA(Arg) 与 N 末端天冬氨酸 (Asp)、谷氨酸 (Glu) 或半胱氨酸 (Cys) 的缀合是该蛋白水解途径的一部分，因为它会导致所得 Arg- 的泛素化。结合蛋白。我们之前观察到 ATE1-/- 胚胎因各种心血管缺陷而死亡。然而，心血管缺陷的确切性质和潜在的分子机制尚不清楚。该项目的总体目标是确定 ATE1 依赖性精氨酰化在心肌生长中的生理作用，并深入了解 ATE1 依赖性蛋白水解途径参与的心血管途径/分子。通过功能蛋白质组学方法鉴定 N 端规则途径的底物以及随后对所选候选底物的初步表征，得出了这样的假设：RGS4、RGS5 和 RGS16 是 ATE1 底物，可能是 ATE1 依赖性心血管系统的基础。 RGS 蛋白是 G(α) 亚基的 GTP 酶激活蛋白 (GAP)，负向调节 G 蛋白偶联受体 (GPCR) 信号传导。 RGS4、RGS5 和/或 RGS16 被认为是心肌生长和血管成熟/完整性的 Gq/Gi 激活信号传导的重要负调节因子。然后我们询问这些 RGS 蛋白被泛素连接酶 (E3) 泛素化以进行蛋白水解的机制。使用基于亲和力的蛋白质组学方法，我们鉴定了一个名为 UBR1-UBR7 的新蛋白质家族，该家族可能对 RGS4、RGS5 和 RGS16 的泛素化起作用。我们的总体假设是，RGS4、RGS5 和 RGS16 的细胞浓度以及它们作为心血管 G 蛋白途径调节剂的功能是通过 MetAPs-O2-ATE1-UBR 蛋白水解级联来调节的。为了解决这一假设和相关问题，我们提出以下目标。目标 1：测试 ATE1 是否对内在心肌生长具有体内作用。目标 2：确定 ATE 1 依赖性精氨酰化对 RGS4、RGS5 和 RGS16 周转的作用。目标 3：阐明 RGS4、RGS5 和 RGS16 泛素化进行蛋白水解的分子机制。目标 4：检查 ATE1 敲除对 G 蛋白通路的生理影响。