May function in the removal and maintenance of calcium homeostasis during signaling in the adult and in signaling events during embryogenesis and patterning of imaginal disks. Transports one Ca(2+) and 1 K(+) in exchange for 4 Na(+). Expressed in the adult nervous system. Expressed in the photoreceptor cells as well as in the lamina, medulla, and optic lobes of the brain. Expressed during ventral nerve cord development in the embryo and in larval imaginal disks. Expressed in a dorsal-ventral pattern in the eye-antennal disk. Partially edited. Target of Adar. Belongs to the Ca(2+):cation antiporter (CaCA) (TC 2.A.19) family. SLC24A subfamily. Contaminating sequence. Potential poly-A sequence.