G Protein signaling at the endosome

内体中的 G 蛋白信号传导

基本信息

批准号：
7425534
负责人：
Henrik G. Dohlman
金额：
$ 5.34万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-05-01 至 2011-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7425534
关键词：
1-Phosphatidylinositol 3-Kinase Affinity Binding Binding Proteins Cell Surface Receptors Cell membrane Cell surface Cells Characteristics Complex Copper Cytoplasm Dissociation Employee Strikes Endosomes Eukaryota Eukaryotic Cell Event Figs - dietary Fungal Genome G Beta Gamma G-Protein-Coupled Receptors GTP Binding GTP-Binding Protein alpha Subunits, Gs GTP-Binding Proteins Green Fluorescent Proteins Guanine Nucleotide Exchange Factors Guanine Nucleotides Guanosine Triphosphate Phosphohydrolases Hormones Human Intracellular Second Messenger Link Maps Mediating Mitogen-Activated Protein Kinases Modeling Molecular Conformation Monitor Neurotransmitters Partner in relationship Pathway interactions Pheromone Pheromone Receptors Phosphatidylinositols Phospholipids Phosphotransferases Physiological Point Mutation Production Protein Overexpression Proteins Recruitment Activity Relative (related person)Research Personnel Role Second Messenger Systems Series Signal Pathway Signal Transduction Signaling Molecule Signaling Protein Site Structure System Testing Transducers Ursidae Family WD Repeat Yeasts human disease hypertension treatment mutant nervous system disorder novel phosphatidylinositol 3-phosphate programs protein function receptor receptor binding research study response rho second messenger yeast protein

项目摘要

Most hormones and neurotransmitters bind to cell surface receptors, activate G proteins, and produce a second messenger that propagates the signal within the cell. In yeast the G-beta/gamma subunits are necessary and sufficient for most aspects of the response to mating pheromones. Recently however,we determined that the G-alpha protein (Gpa1) can also transmit a signal mediated by the only known phosphatidylinositol 3-kinase in yeast (Vps34) and the phospholipid second messenger, Ptdlns 3-P. Notably, Gpa1 and Vps34 are both located at the endosome, far removed from receptors and the G-beta/gamma subunits. Our objective in this proposal is to identify other components of the pathway (receptor, G- beta/gamma, effector target) and the mechanism by which these proteins transmit their signal at the endosome. There are three specific aims: Aim 1. How is the G protein at the endosome activated? We have shown that Gpa1 stimulates Vps34 and Ptdlns 3-P production at the endosome but we do not know how Gpa1 is activated in this case. Our hypothesis is that Gpa1 and Vps34 are activated by internalized pheromone receptors and subsequently by a second exchange factor at the endosome. Aim 2. What are the G-beta/gamma-like proteins at the endosome? We found that the Ptdlns 3-kinase regulatory subunit Vps15 has a 7-WD repeat domain structure typical of that found in G-beta proteins. Our hypothesis is that Vps15 functions as the G-beta subunit at the endosome. Aim 3. How is G protein signaling at the endosome transmitted? We have shown that the Ptdlns 3-P- binding protein Bem1 translocates to the endosome in response to Gpa1 activation. Our hypothesis is that Ptdlns 3-P activates Bem1 and recruits a subset of signaling proteins to the endosome. These findings reveal a surprising new role and a new site of action for this well-characterized signaling molecule. Mechanisms discovered in yeast are usually recapitulated in higher eukaryotes, so the principles elucidated here will likely apply as well to hormone and neurotransmitter function in humans. Just as G protein coupled receptors at the cell surface are proven targets for the treatment of hypertension and diverse neurological disorders, intracellular receptors are likely as well to be useful in treating human disease.

大多数激素和神经递质与细胞表面受体结合，激活 G 蛋白，并产生在细胞内传播信号的第二信使。在酵母中，G-β/γ 亚基是对于交配信息素反应的大多数方面都是必要和充分的。然而最近，我们确定 G-α 蛋白 (Gpa1) 也可以传递由唯一已知的介导的信号酵母中的磷脂酰肌醇 3-激酶 (Vps34) 和磷脂第二信使 Ptdlns 3-P。尤其， Gpa1 和 Vps34 均位于内体，远离受体和 G-beta/gamma 亚单位。我们在此提案中的目标是确定该途径的其他组成部分（受体、G- β/γ，效应器靶标）以及这些蛋白质在内体。具体目标有以下三个：目标 1. 内体上的 G 蛋白是如何被激活的？我们已经证明 Gpa1 刺激 Vps34 和 Ptdlns 3-P 在内体中产生，但我们不知道在这种情况下 Gpa1 是如何被激活的。我们的假设 Gpa1 和 Vps34 被内化信息素受体激活，随后被内体的第二个交换因子。目标 2. 内体中的 G-β/γ 样蛋白是什么？我们发现 Ptdlns 3-激酶调节亚基 Vps15 具有 G-β 蛋白中典型的 7-WD 重复结构域结构。我们的假设 Vps15 在内体中充当 G-β 亚基。目标 3. 内体中的 G 蛋白信号如何传递？我们已经证明 Ptdlns 3-P- 结合蛋白 Bem1 响应 Gpa1 激活而易位至内体。我们的假设是 Ptdlns 3-P 激活 Bem1 并将信号蛋白子集招募到内体。这些发现揭示了这种特征明确的信号传导的令人惊讶的新作用和新的作用位点分子。在酵母中发现的机制通常可以在高等真核生物中重现，因此这些原理这里阐明的可能也适用于人类的激素和神经递质功能。正如G 细胞表面的蛋白质偶联受体已被证明是治疗高血压和多种疾病的靶标神经系统疾病，细胞内受体也可能用于治疗人类疾病。