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XB-ART-49621
Curr Pharm Biotechnol 2014 Jan 01;1510:987-95. doi: 10.2174/1389201015666141031111916.
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G protein-coupled receptor signaling to Kir channels in Xenopus oocytes.

Hatcher-Solis C , Fribourg M , Spyridaki K , Younkin J , Ellaithy A , Xiang G , Liapakis G , Gonzalez-Maeso J , Zhang H , Cui M , Logothetis DE .


Abstract
Kir3 (or GIRK) channels have been known for nearly three decades to be activated by direct interactions with the βγ subunits of heterotrimeric G (Gαβγ) proteins in a membrane-delimited manner. Gα also interacts with GIRK channels and since PTX-sensitive Gα subunits show higher affinity of interaction they confer signaling specificity to G Protein- Coupled Receptors (GPCRs) that normally couple to these G protein subunits. In heterologous systems, overexpression of non PTX-sensitive Gα subunits scavenges the available Gβγ and biases GIRK activation through GPCRs that couple to these Gα subunits. Moreover, all Kir channels rely on their direct interactions with the phospholipid PIP2 to maintain their activity. Thus, signals that activate phospholipase C (e.g. through Gq signaling) to hydrolyze PIP2 result in inhibition of Kir channel activity. In this review, we illustrate with experiments performed in Xenopus oocytes that Kir channels can be used efficiently as reporters of GPCR function through Gi, Gs or Gq signaling. The membrane-delimited nature of this expression system makes it highly efficient for constructing dose-response curves yielding highly reproducible apparent affinities of different ligands for each GPCR tested.

PubMed ID: 25374032
PMC ID: PMC4426293
Article link: Curr Pharm Biotechnol
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: gprc6a kcnj3

References [+] :
Barnard, Translation of exogenous messenger RNA coding for nicotinic acetylcholine receptors produces functional receptors in Xenopus oocytes. 1982, Pubmed, Xenbase