Retinal rod and cone photoreceptors express two distinct sodium/potassium/calcium exchanger (NCKX) gene products [, ]. Both the rod NCKX1 and cone NCKX2 are critical components of the visual transduction cascade, controlling the calcium concentration of outer segments during light and darkness []. This entry represents NCKX2, also known as SLC24A2, which is found in cones, in retinal ganglion cells, and in various parts of the brain [, ]. Both NCKX1 and NCKX2 transport 1 Ca2+ and 1 K+ in exchange for 4 Na+.
