Human Sodium/Potassium/Calcium Exchanger 2, NCKX2 ELI

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(+).