GRK1 and retinal degeneration: The breakdown of this inactivation mechanism due to lack of rhodopsin kinase, arestin-1, or the absence of phosphorylation sites on rhodopsin results in Oguchi disease (a form of night blindness) or retinal degeneration in humans (Apfelstedt-Sylla et al., 1993; Fuchs et al., 1995; Cideciyan et al., 1998), as well as the loss of rod function and retinal degeneration in mice (Chen et al., 1995; Xu et al., 1997; Chen C.K. et al., 1999; Chen J. et al., 1999).