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. Author manuscript; available in PMC: 2025 Jun 24.
Published in final edited form as: J Mol Cell Cardiol. 2022 Jul 22;172:14–23. doi: 10.1016/j.yjmcc.2022.07.008

Figure 2. Subfamily organization and domain mapping of GRKs.

Figure 2.

All GRKs possess a highly conserved amino-terminal (Nt) domain (red) and a Regulator of G protein signaling (RGS) homology (RH) domain (orange), followed by a catalytic (kinase) domain (yellow). The carboxy-terminal (Ct) domain is highly variable between GRK subfamilies. GRK1 and GRK7 comprise the visual or opsin kinase subfamily and possess a unique Nt prenylation site. GRK2 and GRK3 comprise the adrenergic receptor kinase (ARK) GRK subfamily and possess a Ct PH domain that interacts with G protein βγ subunits. The GRK4 subfamily (GRK4, GRK5 and GRK6) is highly variable but share a Ct helix palmitoylation site; additionally, members of this family all possess putative nuclear localization signals, with GRK5 containing both a known nuclear localization signal (dark blue) and a known nuclear export signal (light blue). Numbers above domain maps for each GRK correspond to amino acid residue numbers delineating regions; italicized numbers below domain maps correspond to catalytic lysine (K) residues.