Role of endocytosis in the activation of the extracellular signal-regulated kinase cascade by sequestering and nonsequestering G protein-coupled receptors

作     者：Pierce, KL Maudsley, S Daaka, Y Luttrell, LM Lefkowitz, RJ 

作者机构：Duke Univ Med Ctr Howard Hughes Med Inst Durham NC 27710 USA Duke Univ Med Ctr Dept Med Durham NC 27710 USA Duke Univ Med Ctr Dept Surg Durham NC 27710 USA Duke Univ Med Ctr Dept Biochem Durham NC 27710 USA 

出 版 物：《PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA》 (美国国家科学院汇刊)

年 卷 期：2000年第97卷第4期

页      面：1489-1494页

核心收录：

学科分类：07[理学] 08[工学] 

基　　金：NHLBI NIH HHS [R01 HL016037  HL16037] Funding Source: Medline 

主　　题：肾上腺素能α激动剂/药理学 COS细胞 网格蛋白/代谢 胞吞作用 酶抑制剂 表皮生长因子/药理学 荧光抗体技术 GTP结合蛋白质类/代谢 异丙肾上腺素/药理学 丝裂原激活蛋白激酶类/代谢 磷酰化 喹唑啉类 喹恶啉类/药理学 受体 肾上腺素能α/代谢 受体 肾上腺素能β/代谢 受体 细胞表面/代谢 转染 酪氨酸磷酸化抑制剂/药理学 动物 

摘      要：Acting through a number of distinct pathways, many G protein-coupled receptors (GPCRs) activate the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) cascade. Recently, it has been shown that in some cases, clathrin-mediated endocytosis is required for GPCR activation of the ERK/MAPK cascade, whereas in others it is not. Accordingly, we compared ERK activation mediated by a GPCR that does not undergo agonist-stimulated endocytosis, the alpha(2A) adrenergic receptor (alpha(2A) AR), with ERK activation mediated by the beta(2) adrenergic receptor (beta(2) AR), which is endocytosed. Surprisingly, we found that in COS-7 cells, ERK activation by the alpha(2A) AR, like that mediated by both the beta(2) AR and the epidermal growth factor receptor (EGFR), is sensitive to mechanistically distinct inhibitors of clathrin-mediated endocytosis, including monodansylcadaverine. a mutant dynamin I, and a mutant beta-arrestin 1. Moreover, we determined that, as has been shown for many other GPCRs, both alpha(2A) and beta(2) AR-mediated ERK activation involves transactivation of the EGFR, Using confocal immunofluorescence microscopy, we found that stimulation of the beta(2) AR, the alpha(2A) AR, or the EGFR each results in internalization of a green fluorescent protein-tagged EGFR. Although beta(2) AR stimulation leads to redistribution of both the beta(2) AR and EGFR, activation of the alpha(2A) AR leads to redistribution of the EGFR but the alpha(2A) AR remains on the plasma membrane. These findings separate GPCR endocytosis from the requirement for clathrin-mediated endocytosis in EGFR transactivation-mediated ERK activation and suggest that it is the receptor tyrosine kinase or another downstream effector that must engage the endocytic machinery.