Biochemical and Biophysical Research Communications, Vol.503, No.1, 165-170, 2018
G protein gamma (G gamma) subtype dependent targeting of GRK2 to M3 receptor by G beta gamma
Interactions of cytosolic G protein coupled receptor kinase 2 (GRK2) with activated G protein coupled receptors (GPCRs) induce receptor phosphorylation and desensitization. GRK2 is recruited to active M3-muscarinic receptors (M3R) with the participation of the receptor, G alpha q and G beta gamma. Since we have shown that signaling efficacy of G beta gamma is governed by its G gamma subtype identity, the present study examined whether recruitment of GRK2 to M3R is also G gamma subtype dependent. To capture the dynamics of GRK2-recruitment concurrently with GPCR-G protein activation, we employed live cell confocal imaging and a novel assay based on G beta gamma translocation. Data show that M3R activation-induced GRK2 recruitment is G gamma subtype dependent in which G beta gamma dimers with low PM-affinity G gamma 9 exhibited a two-fold higher GRK2-recruitment compared to high PM affinity G gamma 3 expressing cells. Since 12-mammalian G gamma types exhibit a cell and tissue specific expressions and the PM-affinity of a G gamma is linked to its subtype identity, our results indicate a mechanism by which G gamma profile of a cell controls GRK2 signaling and GPCR desensitization. (C) 2018 Elsevier Inc. All rights reserved.