Referenced in: none

Automatically associated channels: Kir3.4

Title: Specificity of Gbetagamma signaling depends on Galpha subunit coupling with G-protein-sensitive K(+) channels.

Authors: Xian Geng, Xiao-na Du, Radda Rusinova, Bo-Yi Liu, Fang Li, Xuan Zhang, Xing-juan Chen, Diomedes E Logothetis, Hai-lin Zhang

Journal, date & volume: Pharmacology, 2009 , 84, 82-90

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/19590257

Abstract
Many neurotransmitters activate G-protein-gated inwardly rectifying K(+) (Kir3) channels by stimulating G-protein-coupled receptors. However, in native systems, only receptors coupled to pertussis-toxin (PTX)-sensitive G proteins (Gi/Go) have been shown to be able to activate Kir3 channels through the betagamma subunits of G proteins (Gbetagamma), whereas activation of receptors coupled to PTX-insensitive G proteins such as Gq or Gs do not activate Kir3 channels. The question remains as to how signaling specificity is achieved and what are its key determinants. In this study, we have used the Xenopus oocyte expression system to investigate specific activation of Kir3 channels by heterotrimeric G proteins. We have demonstrated the activation of Kir3.4 channels by agonist stimulation of non-PTX-sensitive G proteins under conditions of Galpha subunit overexpression. We present evidence to suggest a key role for the coupling efficiency of Galpha subunits in determining the specificity of Gbetagamma signaling to the channel.