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cAMP-independent G protein signaling in yeast

酵母中不依赖 cAMP 的 G 蛋白信号传导

基本信息

批准号：
8003041
负责人：
Jeanne P. Hirsch
金额：
$ 15.81万
依托单位：
ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-02-12 至 2010-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8003041
关键词：
Address Adenylate Cyclase Affect Affinity Alleles Binding Biochemical Biological Assay Biological Process Catalytic Domain Cell Nucleus Cell surface Cells Complex Cyclic AMP Cyclic AMP-Dependent Protein Kinases Cytoplasm Detection Development Environment GTP Binding GTP-Binding Protein beta Subunits GTP-Binding Proteins Genes Genetic Glucose Goals Growth Guanine Nucleotides Human Hydrolysis In Vitro Measures Mediating Modeling Molecular Nuclear Nutritional Outcome Pathway interactions Phenotype Phosphotransferases Physiological Physiological Processes Population Process Production Protein Isoforms Proteins Reporter Research Personnel Role Saccharomyces cerevisiae Signal Pathway Signal Transduction Signal Transduction Pathway Starvation Stress System Testing Transducers Variant Yeasts extracellular glucose receptor interest mutant novel overexpression programs promoter protein kinase A kinase protein protein interaction receptor coupling research study response transmission process

项目摘要

Pseudohyphal and invasive growth in the yeast Saccharomyces cerevisiae require a signaling pathway that is mediated by the G protein beta-subunit Gpa2p and its coupled receptor Gpr1. Gpr1p is a low affinity glucose receptor that responds to high concentrations of glucose in the environment. Transmission of a signal from Gpr1p to Gpa2p results in phenotypes associated with high levels of intracellular cAMP. We have recently identified KRH1 and KRH2 as genes that encode components of the Gpa2p signaling pathway. We have shown that Krh1p and Krh2p act downstream of adenylyl cyclase to inhibit protein kinase A (PKA) by a process that does not involve production of intracellular cAMP. Activation of Gpa2p is thought to relieve the inhibition of PKA by Krh1p and Krh2p, resulting in high levels of PKA activity. The long-term objectives of this project are: 1) To obtain a complete description of the molecular processes that comprise the Gpa2p signal transduction pathway; 2) To understand the biological function of the Gpa2p pathway in terms of an entire cell population undergoing pseudohyphal growth. The first specific aim of this project is to determine how Krh1p and Krh2p regulate PKA. These studies will investigate whether binding of Krh1p and Krh2p to PKA is direct and whether binding inhibits PKA kinase activity. The second specific aim is to determine whether Krh1p and Krh2p control signaling by affecting the localization of PKA. The third specific aim is to investigate whether the GTP-bound form of Gpa2p blocks the inhibitory function of Krh1p and Krh2p by determining the effects of non-activatable and constitutive alleles of GPA2 on Krh1p and Krh2p function. The fourth specific aim is to test whether Gpa2p is specifically activated in cells at the edge of a growing colony in order to suppress stress and starvation responses and to promote growth and pseudohyphal development. The goal of this aim is to develop a reporter system to allow detection of activated Gpa2p at the level of a whole colony undergoing pseudohyphal growth. These studies will provide new information about G protein-mediated signaling pathways, which are essential for the proper functioning of many physiological processes in humans.

酿酒酵母中的假菌丝和侵入性生长需要由 G 蛋白 β 亚基 Gpa2p 及其偶联受体 Gpr1 介导的信号传导途径。 Gpr1p 是一种低亲和力葡萄糖受体，可对环境中的高浓度葡萄糖做出反应。信号从 Gpr1p 传输到 Gpa2p 会导致与高水平细胞内 cAMP 相关的表型。我们最近发现 KRH1 和 KRH2 是编码 Gpa2p 信号通路成分的基因。我们已经证明，Krh1p 和 Krh2p 作用于腺苷酸环化酶下游，通过不涉及细胞内 cAMP 产生的过程抑制蛋白激酶 A (PKA)。 Gpa2p 的激活被认为可以缓解 Krh1p 和 Krh2p 抑制 PKA，导致高水平的 PKA 活性。该项目的长期目标是： 1）获得构成Gpa2p信号转导途径的分子过程的完整描述； 2) 了解 Gpa2p 通路在整个细胞群假菌丝生长过程中的生物学功能。该项目的第一个具体目标是确定 Krh1p 和 Krh2p 如何调节 PKA。这些研究将调查 Krh1p 和 Krh2p 与 PKA 的结合是否是直接的，以及结合是否会抑制 PKA 激酶活性。第二个具体目标是确定 Krh1p 和 Krh2p 是否通过影响 PKA 的定位来控制信号传导。第三个具体目标是通过确定 GPA2 的不可激活和组成型等位基因对 Krh1p 和 Krh2p 功能的影响，研究 Gpa2p 的 GTP 结合形式是否阻断 Krh1p 和 Krh2p 的抑制功能。第四个具体目标是测试 Gpa2p 是否在生长菌落边缘的细胞中被特异性激活，以抑制应激和饥饿反应并促进生长和假菌丝发育。该目标的目标是开发一个报告系统允许在整个菌落水平上检测激活的 Gpa2p 假菌丝生长。这些研究将提供有关 G 蛋白介导的信号传导途径的新信息，这对于人类许多生理过程的正常运作至关重要。