Molecular mechanism of trafficking regulation of G protein-coupled receptor

2015 Fiscal Year Final Research Report

• Project/Area Number: 25460326
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: General pharmacology
• Research Institution: Shiga University of Medical Science (2014-2015); Hokkaido University (2013)
• Principal Investigator: Terada Koji 滋賀医科大学, 医学部, 准教授 (70342722)
• Co-Investigator(Renkei-kenkyūsha): MIWA Soichi 北海道大学, 大学院医学研究科, 教授 (40157706)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: エンドセリン / ユビキチン / エンドサイトーシス / リサイクリング

Outline of Final Research Achievements

Two types of G protein-coupled receptors for endothelin-1 (ET-1), ET type A receptor (ETAR) and ETBR, resemble each other, but upon ET-1 stimulation, they follow different intracellular trafficking pathways. In this study, we showed that ETBR but not ETAR was ubiquitinated upon ET-1 stimulation, and that ETBR was internalized and degraded in lysosome more rapidly than ETAR. The mutant ETBR (designated “5KR mutant”) in which 5 lysine residues in C-tail were substituted to arginine was not ubiquitinated, and its rates of internalization and degradation after ET-1 stimulation became slower. Confocal microscopic study showed that following ET-1 stimulation, ETAR and 5KR mutant of ETBR were co-localized mainly with Rab11, a marker of recycling endosome, whereas ETBR was with Rab7, a marker of late endosome/lysosome. These results demonstrate that agonist-induced ubiquitination in C-tail of ETBR switches intracellular trafficking from recycling to plasma membrane to targeting to lysosome.

Free Research Field

生化学、分子薬理学