Symbol GRK1 Entrez 6011 OMIM 180381 | Alt. symbols RHOK HUGO 10013 RefSeq NM_002929 | |
Rhodopsin kinase (EC 2.7.11.14, cone opsin kinase, G-protein-coupled receptor kinase 1, GPCR kinase 1, GRK1, GRK7, opsin kinase, opsin kinase (phosphorylating), rhodopsin kinase (phosphorylating), RK, STK14) is a serine/threonine-specific protein kinase involved in phototransduction. This enzyme catalyses the following chemical reaction
ATP + rhodopsinMutations in rhodopsin kinase are associated with a form of night blindness called Oguchi disease.
More on Rhodopsin Kinase
Rhodopsin Kinase is involved in mammalian rod cells specifically with photo transduction. G coupled-protein receptor kinases are the family that rhodopsin kinase belong to. This kinase is referred to as GRK1 and phosphorylates rhodopsin resulting in partial photo-activation of rhodopsin activating the dim flash response. Dim flash response is activated in dim light and its ideal to de-activate the rod cell photoreceptor or rhodopsin over time. GRK1 AND GRK7 exist and are isoforms of rhodopsin kinase. Studies have proven that in mice rod cells, GRK1 has competition with arrestin-1 for the binding site of rhodopsin. Arrestin-1 when bound to rhodopsin inhibits signaling and turns off photo-transduction completely. As with any enzyme, rhodopsin kinase has a regulator or inhibitor known as recoverin. In the dark state of the rod cells recoverin inhibits rhodopsin kinase. Specifically, a study has proven that GRK1 acts on the cytoplasmic loops of rhodopsin both the second and third loops. The cytoplasmic loops act specifically where transducin binds to rhodopsin so this allows GRK1 and transducin to compete for the binding site on rhodopsin. With recoverin present, it exists between GRK1 and rhodopsin and it was shown that when bound competition between GRK1 and transducin suppressed .