G protein-coupled receptor kinase 1 (GRK1)

G protein-coupled receptor kinase 1 (GRK1), commonly referred to as rhodopsin kinase, is an enzyme predominantly expressed in retinal rod cells. It phosphorylates activated rhodopsin following light stimulation, initiating receptor desensitization by recruiting arrestins and thereby terminating phototransduction signaling[2][3]. This phosphorylation is essential for the recovery phase of vision and prevents continuous activation of the light response. Structurally, GRK1 features a central kinase domain within a regulator of G protein signaling homology (RH) domain, an N-terminal α-helix, and a membrane-targeting C-terminal region; it belongs to the AGC kinase subfamily[2][3][4]. Loss-of-function mutations in GRK1 are associated with congenital stationary night blindness (Oguchi disease), highlighting its critical physiological role in visual processes[2][3]. No clinically approved drugs target GRK1 specifically, but it remains an important molecular target for the investigation of GPCR regulation, retinal disease mechanisms, and potential therapeutic development.

Other names

Rhodopsin kinaseGRK1RHOKRKGPRK1

Kinase inhibition (potential mechanism in experimental settings; e.g., small molecule inhibitors reduce phosphorylation activity) Modulation of GRK1 function could alter GPCR desensitization, arrestin recruitment, and visual signaling.