Function
Rhodopsin kinase (RK) is an enzyme which catalyzes the conversion of rhodopsin and ATP to phosphorhodopsin and ADP. RK is retina-specific and the phosphorylation of rhodopsin initiates the phototransduction cascade[1]. The rapid desensitization permits rapid adaptation to changes in illumination. RK is inhibited by the neuronal calcium-binding protein recoverin.
Disease
Mutations in RK are associated with night blindness[2].
Structural highlights
The active site of RK is located between its small and large lobes and contains the nucleotide and Mg+2 ion[3]. An Asp residue is the catalytic base residue. Water molecules are shown as red spheres.
- ↑ Kuhn H, Wilden U. Deactivation of photoactivated rhodopsin by rhodopsin-kinase and arrestin. J Recept Res. 1987;7(1-4):283-98. PMID:3040978
- ↑ Yamamoto S, Sippel KC, Berson EL, Dryja TP. Defects in the rhodopsin kinase gene in the Oguchi form of stationary night blindness. Nat Genet. 1997 Feb;15(2):175-8. PMID:9020843 doi:https://dx.doi.org/10.1038/ng0297-175
- ↑ Singh P, Wang B, Maeda T, Palczewski K, Tesmer JJ. Structures of rhodopsin kinase in different ligand states reveal key elements involved in G protein-coupled receptor kinase activation. J Biol Chem. 2008 May 16;283(20):14053-62. Epub 2008 Mar 13. PMID:18339619 doi:10.1074/jbc.M708974200