Structural Basis for Binding to G Protein Beta Gamma

与 G 蛋白 Beta Gamma 结合的结构基础

• 批准号: 7237253
• 负责人: Alan V. Smrcka
• 金额: $ 31.73万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7237253
• 关键词: Structural; Basis; Binding; Protein; Beta

DESCRIPTION (provided by applicant): The betagamma subunits from heterotrimeric G proteins occupy a central position in the G protein-coupled receptor system. They are multifaceted proteins that have determinants to specify interactions with G protein-coupled receptors, G protein alpha subunits, and multiple downstream target effector molecules. While the three dimensional structure for this protein has been solved, the structural and biochemical features that are responsible for functional interactions with protein partners are not understood. A major goal of our laboratory has been to understand the nature of the interactions between betagamma subunits and its various binding partners. In the course of the last funding period we obtained evidence that G protein betagamma subunits have a unique surface, with properties similar to protein-protein interaction "hot spots," that is critical for mediating effector recognition and regulation. Surprisingly, we found that peptides that bind to this surface activate signal transduction pathways in living cells via a mechanism that does not involve receptors or nucleotide exchange on the alpha subunit. G protein coupled receptor and nucleotide exchange-independent mechanisms for activation of G protein signaling are emerging as playing important regulatory roles in biology. Our identification of a novel mechanism for receptor independent G protein activation suggests another pathway that could be utilized in a cellular context to regulate G protein betagamma subunit signaling. This proposal will explore the mechanisms and physiological implications for this novel G protein activation process in the following specific aims: 1. Determination of the nature of the protein recognition surface on betagammasubunits and its role in a novel nucleotide exchange-independent mechanism for betagamma subunit release. 2. Determination of the mechanism for activation of betagamma-dependent signal transduction in living cells by cell permeable peptides that mediate nucleotide exchange-independent G protein subunit dissociation. 3. Identification of cellular factors that mediate nucleotide exchange-independent subunit dissociation. 4. Identification of sites of interaction G protein betagamma subunits with cellular targets using deuterium exchange mass spectrometry.

描述（由申请人提供）：来自异三聚体G蛋白的betagamma亚基在G蛋白偶联受体系统中占中心位置。它们是具有决定因素的多面蛋白，可以指定与G蛋白偶联受体，G蛋白α亚基和多个下游靶效应分子的相互作用。虽然已解决了该蛋白质的三维结构，但尚不了解导致与蛋白质伴侣功能相互作用的结构和生化特征。我们实验室的一个主要目标是了解Betagamma亚基与其各种约束伙伴之间相互作用的性质。在最后一个资金期间，我们获得了G蛋白Betagamma亚基的证据，其特性类似于蛋白质 - 蛋白质相互作用“热点”，这对于介导效应子识别和调节至关重要。令人惊讶的是，我们发现与该表面结合的肽通过不涉及α亚基上受体或核苷酸交换的机制激活活细胞中的信号转导途径。 G蛋白偶联受体和核苷酸交换非依赖性G蛋白信号传导的机制已成为生物学中重要的调节作用。我们对一种新型受体G蛋白激活机制的鉴定表明，可以在细胞环境中使用的另一种途径来调节G蛋白Betagamma亚基信号传导。该建议将在以下特定目的中探索对这一新型G蛋白激活过程的机制和生理意义：1。确定贝塔加马硫基亚基上蛋白质识别表面的性质及其在新型核苷酸交换机制中的作用来确定betagamma subunit释放的新型核苷酸交换机制。 2。确定通过可渗透肽介导核苷酸交换依赖性G蛋白亚基分离的细胞渗透肽激活活细胞中Betagamma依赖性信号转导的机制。 3。鉴定介导核苷酸交换非依赖性亚基解离的细胞因子。 4。使用氘交换质谱法鉴定与细胞靶标的相互作用G蛋白Betagamma亚基的位点。