The outer segment of retinal rod and cone photoreceptors contains electrogenic sodium-calcium exchangers which mediate a light-induced decrease in free calcium concentration. This function in cones is performed by SLC24A2 (Prinsen et al., 2000 [PubMed 10662833]).[supplied by OMIM].
Critical component of the visual transduction cascade, controlling the calcium concentration of outer segments during light and darkness. Light causes a rapid lowering of cytosolic free calcium in the outer segment of both retinal rod and cone photoreceptors and the light-induced lowering of calcium is caused by extrusion via this protein which plays a key role in the process of light adaptation. Transports 1 Ca(2+) and 1 K(+) in exchange for 4 Na(+).