Recoverin is a 23 kilodalton (kDa) neuronal calcium-binding protein that is primarily detected in the photoreceptor cells of the eye. It plays a key role in the inhibition of rhodopsin kinase, a molecule which regulates the phosphorylation of rhodopsin. A reduction in this inhibition helps regulate sensory adaptation in the retina, since the light-dependent channel closure in photoreceptors causes calcium levels to decrease, which relieves the inhibition of rhodopsin kinase by calcium-bound recoverin, leading to a more rapid inactivation of metarhodopsin II (activated form of rhodopsin).
