Overview:

GRK7 is a member of the G protein-coupled receptor kinase subfamily and is a Ser/Thr protein kinase. GRK7 is specifically expressed in the retina and has been shown to phosphorylate cone opsins and initiate their deactivation (1). GRK7 catalyzes rhodopsin phosphorylation in a light-dependent manner. GRK7 co-localizes with GRK1 in human cone outer segments. PKA phosphorylates GRK7 at Ser(23) and Ser(36) in vitro and phosphorylation of GRK7 by PKA reduces the ability of GRK7 to phosphorylate rhodopsin in vitro (2). Since exposure to light causes a decrease in cAMP levels in rod cells, it is proposed that phosphorylation of GRK7 by PKA occurs in the dark.

Gene Aliases:

GPRK7

Genbank Number:

NM_139209

References:

1. Chen, C-K. et al: Characterization of human GRK7 as a potential cone opsin kinase. Molec. Vision 7: 305-313, 2001.

2. Horner, T J. et al: Phosphorylation of GRK1 and GRK7 by cAMP-dependent protein kinase attenuates their enzymatic activities. J Biol Chem. 2005 Aug 5;280(31):28241-50.