Referenced in: none

Automatically associated channels: Kir2.1 , Kir3.1

Title: G beta gamma directly binds to the carboxyl terminus of the G protein-gated muscarinic K+ channel, GIRK1.

Authors: A Inanobe, K I Morishige, N Takahashi, H Ito, M Yamada, T Takumi, H Nishina, K Takahashi, Y Kanaho, T Katada

Journal, date & volume: Biochem. Biophys. Res. Commun., 1995 Jul 26 , 212, 1022-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/7626088

Abstract
beta gamma Subunits of heterotrimeric GTP-binding proteins (G beta gamma) activate the inwardly rectifying muscarinic K+ channel, GIRK1. The significant role for the carboxyl (C) terminus of GIRK1 in this interaction has been suggested. However, it is still unknown whether G beta gamma directly interacts with GIRK1. To elucidate the molecular basis of G beta gamma-activation of GIRK1, we examined the binding properties of G beta gamma to the C terminus of GIRK1 cloned from mouse brain cDNA library (MB-GIRK1). The C terminus of MB-GIRK1 fused with glutathione S-transferase directly bound to purified G beta gamma. Incubation of the C terminus with Gi pretreated with GTP gamma S, but not with GDP, resulted in the binding of Gi beta gamma to the protein. Purified G alpha-GDP, but not G alpha-GTP gamma S, inhibited the binding of G beta gamma to the fusion protein. These results indicate that G beta gamma dissociated from G alpha may directly bind to the C terminus of GIRK1.