Identification of a GABAB Receptor Subunit, gb2, Required for Functional GABAB Receptor Activity

• DOI: 10.1074/jbc.274.12.7607
• Publication Date: 2002-07-26T15:11:54Z
• Authors: Gordon Y.K. Ng; Janet Clark; Nathalie Coulombe; Nathalie Ethier; Terence E. Hebert; Richard Sullivan; Stacia Kargman; Anne Chateauneuf; Naohiro Tsukamoto; Terry McDonald; Paul Whiting; Éva Mezey; Michael P. Johnson; Qingyun Liu; Lee F. Kolakowski; Jilly F. Evans; Tom I. Bonner; Gary P. O'Neill
• Keywords: GABAB receptor

G protein-coupled receptors are commonly thought to bind their cognate ligands and elicit functional responses primarily as monomeric receptors. In studying the recombinant gamma-aminobutyric acid, type B (GABAB) receptor (gb1a) a GABAB-like orphan (gb2), we observed that both functionally inactive when expressed individually in multiple heterologous systems. Characterization of tissue distribution each by situ hybridization histochemistry rat brain revealed co-localization gb1 gb2 transcripts many regions, suggesting hypothesis may interact vivo. three established systems (inwardly rectifying K+ channel currents Xenopus oocytes, melanophore pigment aggregation, direct cAMP measurements HEK-293 cells), GABA mediated response cells coexpressing gb1a but not expressing either individually. This activity could be blocked with GABAB antagonist CGP71872. COS-7 receptors, co-immunoprecipitation was demonstrated, indicating act subunits formation receptor.