cAMP-independent G protein signaling in yeast

酵母中不依赖 cAMP 的 G 蛋白信号传导

• 批准号: 6914591
• 负责人: Jeanne P. Hirsch
• 金额: $ 26.95万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6914591
• 关键词: G protein; Saccharomyces cerevisiae; alleles; bioassay; biological signal transduction; cell biology; cell growth regulation; cell population study; cell surface receptors; enzyme inhibitors; fungal genetics; fungal proteins; gene expression; genetic regulation; genetic techniques; green fluorescent proteins; microbiology; microorganism reproduction; protein kinase A; protein localization; protein protein interaction; protein structure; receptor coupling; reporter genes

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.

酿酒酵母中酵母糖疗法的伪氢和侵袭性生长需要一个由G蛋白β-亚基GPA2P介导的信号传导途径及其偶联受体GPR1。 GPR1P是一种低亲和力葡萄糖受体，对环境中高浓度的葡萄糖做出反应。信号从GPR1P传播到GPA2P会导致与高水平的细胞内cAMP相关的表型。我们最近将KRH1和KRH2识别为编码GPA2P信号通路组件的基因。我们已经表明，KRH1P和KRH2P通过不涉及细胞内cAMP产生的过程抑制蛋白激酶A（PKA）的下游来抑制蛋白激酶A（PKA）。人们认为激活GPA2P可以缓解 KRH1P和KRH2P对PKA的抑制作用，导致PKA活性较高。该项目的长期目标是：1）获得包含GPA2P信号转导途径的分子过程的完整描述； 2）从经历伪氢生长的整个细胞群体方面，了解GPA2P途径的生物学功能。 该项目的第一个具体目的是确定KRH1P和KRH2P如何调节PKA。这些研究将研究KRH1P和KRH2P与PKA的结合是否是直接的，以及结合是否抑制PKA激酶活性。第二个具体目的是确定KRH1P和KRH2P控制信号是否通过影响PKA的定位来确定。第三个具体目的是研究GPA2P的GTP结合形式是否通过确定GPA2对KRH1P和KRH2P函数的不可活跃和本构等位基因的影响是否通过确定不可活跃和本构等位基因的影响来阻止KRH1P和KRH2P的抑制作用。第四个具体目的是测试GPA2P是否在生长菌落边缘的细胞中特异性激活，以抑制压力和饥饿反应并促进生长和假氢发展。这个目标的目的是开发 记者系统允许在整个菌落的水平上检测激活的GPA2P 假氢生长。这些研究将提供有关G蛋白介导的信号通路的新信息，这对于人类许多生理过程的正确运作至关重要。