G Protein signaling at the endosome

内体中的 G 蛋白信号传导

• 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
• 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

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A 第二使电池内信号传播的信使。在酵母中，G-Beta/Gamma亚基是 对于对交配信息素的响应的大多数方面来说，必要且足够。但是最近，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都位于内体，远离受体和G-Beta/Gamma 亚基。我们在此提案中的目标是确定途径的其他组成部分（受体，g- β/伽马，效应子靶标）以及这些蛋白在其处传输信号的机制 内体。有三个特定的目标： 目标1。内体的G蛋白如何激活？我们已经证明GPA1刺激VPS34和 PTDLNS 3-P在内体处产生，但我们不知道在这种情况下如何激活GPA1。我们的 假设是GPA1和VPS34被内在的信息素受体激活，随后由 内体的第二交换因子。 AIM 2。内体的G-Beta/Gamma样蛋白是什么？我们发现PTDLNS 3激酶 调节亚基VPS15具有G-Beta蛋白中典型的7-WD重复域结构。我们的 假设是VPS15在内体处充当G-Beta亚基。 目标3。内体的G蛋白信号如何传播？我们已经证明了PTDLNS 3-P- 结合蛋白BEM1响应GPA1激活而易位到内体。我们的假设是 PTDLNS 3-P激活BEM1，并将信号蛋白的子集募集到内体。 这些发现揭示了令人惊讶的新角色和新的作用现场，用于这种良好的信号 分子。在酵母中发现的机制通常在较高的真核生物中概括，因此原理 这里阐明的可能也适用于人类的激素和神经递质功能。就像g一样 细胞表面的蛋白质偶联受体已被证明是治疗高血压和多样的靶标 神经系统疾病，细胞内受体也可能在治疗人类疾病中有用。