Regulation of EGF Receptors by G protein receptor

G蛋白受体对EGF受体的调节

• 批准号: 6785962
• 负责人: John R Raymond
• 金额: $ 21.83万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6785962
• 关键词: G protein; G protein coupled receptor kinase; acidity /alkalinity; biological signal transduction; cell component structure /function; epidermal growth factor; green fluorescent proteins; growth factor receptors; immunoprecipitation; intermolecular interaction; intracellular transport; lysosomes; membrane transport proteins; metalloendopeptidases; microinjections; molecular site; neutralizing antibody; phosphorylation; proteasome; protein kinase C; protein localization; protein structure function; protein tyrosine kinase; receptor expression; receptor mediated endocytosis; tissue /cell culture

DESCRIPTION (provided by applicant): The purpose of this application is to explore the cross talk that occurs between G protein-coupled receptors (GPCR's) and receptor tyrosine kinases (RTK's), especially the epidermal growth factor receptor (EGFR). We, like others, have made the observation that activation of GPCR's leads to transphosphorylation and activation of EGFR's. We have also made the novel finding that prior activation of GPCR's leads to a profound desensitization of the EGFR's. The purpose of this application is to gain mechanistic insights into the desensitization process. In Specific Aim 1, we will determine which signaling pathway(s) is/are required for desensitization and transphosphorylation of the EGF receptor by GPCR's. We will mainly use primary cultures of cell types that have endogenous GPCR's and EGFR's. Those studies will be augmented by judicious use of transfected cells. Major questions to be answered in this aim are: What signaling molecules link GPCR activation to EGFR phosphorylation and transactivation? Are they the same as those that induce EGFR desensitization? We will focus primarily on the roles of protein kinase C, the non-receptor tyrosine kinase Src, and sodium proton exchanger type I (NHE-I). Is endocytosis of EGFR required for GPCR-mediated desensitization of EGFR? Is heparin-bound EGF (HB-EGF) required for either desensitization or transactivation of the EGFR? In order to answer this question, we will use a number of complementary methods to neutralize the native HB-EGF in primary cells in culture. In Specific Aim 2, we will determine the intracellular fate of the EGFR's after stimulation of GPCR's. To what compartments are the EGFR targeted after transactivation by GPCR' s? What other signaling components are internalized with the EGFR (GPCR, NRTK, NHE-1, HB-EGF), and are they processed through the same pathways? What enzymatic pathways are required for down-regulation of the EGFR? We will study the roles of lysosomes, proteasome, and zinc-regulated metalloproteinases in this process. These studies address important gaps in our knowledge of GPCR signals that regulate the functions of RTK's.

描述（由申请人提供）：本申请的目的是 探索 G 蛋白偶联受体 (GPCR) 之间发生的串扰 和受体酪氨酸激酶 (RTK)，尤其是表皮生长因子 受体（EGFR）。我们和其他人一样，观察到激活 GPCR 导致 EGFR 的转磷酸化和激活。我们还有 做出了新的发现，即 GPCR 的预先激活会导致深远的影响 EGFR 脱敏。该应用程序的目的是获得 对脱敏过程的机械见解。 在具体目标 1 中，我们将确定需要哪些信号通路 通过 GPCR 对 EGF 受体进行脱敏和转磷酸化。我们 将主要使用具有内源性 GPCR 的细胞类型的原代培养物 EGFR的。这些研究将通过明智地使用转染细胞而得到加强。 该目标需要回答的主要问题是：哪些信号分子相互连接 GPCR 激活导致 EGFR 磷酸化和反式激活？他们是一样的吗 那些诱导 EGFR 脱敏的药物？我们将主要关注角色 蛋白激酶 C、非受体酪氨酸激酶 Src 和钠质子 I 型交换器 (NHE-I)。 GPCR 介导是否需要 EGFR 内吞作用 EGFR脱敏？肝素结合 EGF (HB-EGF) 是否需要 EGFR 脱敏还是反式激活？为了回答这个问题 问题，我们将使用许多补充方法来抵消 培养的原代细胞中存在天然 HB-EGF。 在具体目标 2 中，我们将确定 EGFR 的细胞内命运 GPCR 的刺激。 EGFR 靶向哪些区室 GPCR 的反式激活？还有哪些其他信号成分被内化 与 EGFR (GPCR、NRTK、NHE-1、HB-EGF) 一起，并且它们是通过 相同的途径？下调该酶需要什么酶途径 表皮生长因子受体？我们将研究溶酶体、蛋白酶体和锌调节的作用 金属蛋白酶参与这个过程。这些研究解决了我们的重要差距 了解调节 RTK 功能的 GPCR 信号。