Role of Gbeta 2 in the Nucleus of Angiotensin Receptor Activated Cells

Gbeta 2 在血管紧张素受体激活细胞核中的作用

• 批准号: 8098947
• 负责人: ANUSHREE BHATNAGAR
• 金额: $ 4.94万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8098947
• 关键词: Actinin; Acute; Angiotensin II; Angiotensin II Receptor; Angiotensin Receptor; Angiotensins; Antihypertensive Agents; Binding; Biochemical; Biological; Biological Assay; Blood Pressure; Calcium; Calcium-Binding Proteins; Cardiovascular Physiology; Cell Nucleus; Cell Surface Receptors; Cell membrane; Cells; Chromatin; Chromatin Remodeling Factor; Chymosin; Clinical Trials; Co-Immunoprecipitations; Complex; Congestive Heart Failure; Dissociation; Enzymes; Event; Face; G Protein-Coupled Receptor Signaling; G-Protein-Coupled Receptors; GTP-Binding Proteins; Gene Chips; Gene Expression; Gene Expression Regulation; Goals; HDAC5 gene; Heterotrimeric G Protein Subunit; Heterotrimeric GTP-Binding Proteins; Histones; Hormones; Link; Mass Spectrum Analysis; Mediating; Membrane; Membrane Lipids; Messenger RNA; Microarray Analysis; Modification; Molecular; Mutagenesis; Nuclear; Nuclear Protein; Nuclear Proteins; Nuclear Translocation; Organ; Pharmaceutical Preparations; Physiological; Prevention; Protein Kinase; Proteins; Proteome; RNA Interference; Receptor Activation; Role; Scaffolding Protein; Signal Transduction; Site-Directed Mutagenesis; Specificity; System; Transducers; Water-Electrolyte Balance; alpha Actinin; chromatin remodeling; knock-down; novel; polypeptide; programs; protein complex; protein protein interaction; receptor; release of sequestered calcium ion into cytoplasm; tool; transcription factor

DESCRIPTION (provided by applicant): The rennin-angiotensin system hormone, angiotensin II (Ang II) is a master regulator of normal cardiovascular physiology. Normally, Ang II regulates acute changes in blood pressure and water-electrolyte balance. Under pathological conditions, Ang II modulates gene expression leading to a remodeling program in the target cells. Both types of Ang II actions are mediated by AT1 receptors. Antagonists of AT1 receptor are used in antihypertensive therapy and are currently in clinical trial for prevention of congestive heart failure and other types of end organ damage. These drugs reverse the remodeling gene expression changes in addition to controlling the acute actions of Ang II. Therefore, a mechanistic understanding of modulation of gene expression by AT1 receptor is essential. We approached this problem by tracking protein-protein interactions in the nuclear compartment of Ang II receptor activated cells. To identify novel protein complexes involved in the modulation of gene expression, we analyzed nuclear proteome of AT1 receptor-activated cells by high throughput mass-spectrometry. Among the candidate proteins that translocated to the nucleus, the G-protein beta2 (G(32) subunit polypeptide was a surprising finding. GP is a component of heterotrimeric G proteins which are vital transducers of GPCR signals. Activation of a GPCR, such as AT1 receptor upon Ang II binding, causes catalytic dissociation of G-proteins into Gpy and Got subunits which in turn activate their respective effectors. The GP and Gy subunits always remain in complex and they are generally tethered to the inner face of the plasma membrane by lipid modifications on Gy. Therefore, the GP has traditionally been thought to transduce signals at plasma membrane and has never been shown to be part of the nuclear proteome. We found that Gp2 translocated into the nucleus upon AT1 receptor activation and formed a complex with HDAC5 and alpha-actinin-4. Actinin-4 is a calcium binding protein and HDAC5 is a chromatin remodeling enzyme. Hence, we hypothesize that Ang II activated AT1 receptor stimulates nuclear translocation of GP and assembly of a calcium sensitive chromatin remodeling complex involving actinin-4 and HDAC5. The goals of this project are (i) to determine the specificity of interaction between these three molecules using mutagenesis and Biacore analysis and (ii) to establish the functional significance of this complex formation by microarray analysis of AT1 receptor-dependent gene expression in RNAi knock-down of Gbeta 2 in cells. Our proposed studies will demonstrate a novel mode of control of gene expression by a GPCR.

描述（由申请人提供）：肾素 - 血管紧张素系统激素，血管紧张素II（ANG II）是正常心血管生理学的主要调节剂。通常，ANG II调节血压和水电解质平衡的急性变化。在病理条件下，ANG II调节基因表达，从而导致目标细胞中的重塑程序。两种类型的ANG II作用都是由AT1受体介导的。 AT1受体的拮抗剂用于降压治疗，目前正在临床试验中预防充血性心力衰竭和其他类型的最终器官损伤。除了控制ANG II的急性作用外，这些药物反转了重塑基因表达的变化。因此，必须对通过AT1受体对基因表达调节的调节的机械理解至关重要。我们通过跟踪ANG II受体活化细胞的核区室中的蛋白质蛋白质相互作用来解决这个问题。为了鉴定与基因表达调节有关的新型蛋白质复合物，我们通过高吞吐量质谱法分析了AT1受体激活细胞的核蛋白质组。 Among the candidate proteins that translocated to the nucleus, the G-protein beta2 (G(32) subunit polypeptide was a surprising finding. GP is a component of heterotrimeric G proteins which are vital transducers of GPCR signals. Activation of a GPCR, such as AT1 receptor upon Ang II binding, causes catalytic dissociation of G-proteins into Gpy and Got subunits which反过来，它们各自的效应子。 HDAC5和α-肌动蛋白4。该项目的目标是（i）使用诱变和BIACORE分析确定这三个分子之间的相互作用的特异性，以及（ii）通过对细胞中GBETA 2的RNAI基因敲除中AT1受体依赖性基因表达的微阵列分析来确定该复合物形成的功能意义。我们提出的研究将证明GPCR对基因表达的一种新型控制方式。