※ GRK family introduction

    GRK (G protein-coupled receptor (GPCR) kinases), belong to the AGC family, are characterized by its role in relation with GPCR. GPCRs are multi-domain proteins, including an N-termainal unique region, a regulator of G protein signaling (RGS) homology domain (RH) and a kinase catalytic domain. The C-terminal domain is involved in their membrane targeting. GRK isoforms have been shown to target to specialized membrane compartments in specific cell types, which is suggested to have relation with their specific function. GRK is directly activated by docking with active GPCRs and GRK can phosphorylate the Serine/Threonine residue on active GPCR and regulation de downstream signaling. Besides GPCR, GRK can also mediate the phosphorylation of non-GPCR receptors including LRP6, PDGFRb, DREAM, NFkB1 and Nedd4, and involved in specific cellular processes or cell signaling cascade (1).

Reference
1. Gurevich, E.V., Tesmer, J.J., Mushegian, A. and Gurevich, V.V. (2012) G protein-coupled receptor kinases: more than just kinases and not only for GPCRs. Pharmacol Ther, 133, 40-69. PMID: 21903131