XB-ART-18880
J Biol Chem
1995 Dec 15;27050:30068-74.
Show Gene links
Show Anatomy links
The G protein beta gamma subunit transduces the muscarinic receptor signal for Ca2+ release in Xenopus oocytes.
???displayArticle.abstract???
At least 30 G protein-linked receptors stimulate phosphatidylinositol 4,5-bisphosphate phosphodiesterase (phospholipase C beta, PLC beta) through G protein subunits to release intracellular calcium from the endoplasmic reticulum (Clapham, D. E. (1995) Cell 80, 259-268). Although both G alpha and G beta gamma G protein subunits have been shown to activate purified PLC beta in vitro, G alpha q has been presumed to mediate the pertussis toxin-insensitive response in vivo. In this study, we show that G beta gamma plays a dominant role in muscarinic-mediated activation of PLC beta by employing the Xenopus oocyte expression system. Antisense nucleotides and antibodies to G alpha q/11 blocked the m3-mediated signal transduction by inhibiting interaction of the muscarinic receptor with the G protein. Agents that specifically bound free G beta gamma subunits (G alpha-GDP and a beta-adrenergic receptor kinase fragment) inhibited acetylcholine-induced signal transduction to PLC beta, and injection of G beta gamma subunits into oocytes directly induced release of intracellular Ca2+. We conclude that receptor coupling specificity of the G alpha q/G beta gamma heterotrimer is determined by G alpha q; G beta gamma is the predominant signaling molecule activating oocyte PLC beta.
???displayArticle.pubmedLink??? 8530411
???displayArticle.link??? J Biol Chem
???displayArticle.grants???
Species referenced: Xenopus
Genes referenced: gnaq