Calcium, potassium:sodium antiporter that transports 1 Ca(2+) and 1 K(+) in exchange for 4 Na(+) (By similarity). Required for learming and memory by regulating neuronal Ca(2+), which is essential for the development of synaptic plasticity (PubMed:16407245). Ca(2+)(out) + K(+)(out) + 4 Na(+)(in) = Ca(2+)(in) + K(+)(in) + 4 Na(+)(out) Mice display a significan reduction in Ca(2+) flux in cortical neurons, leading to a profound loss of long term potentiation and an increase in long term depression at hippocampal Schaffer/CA1 synapses, and clear deficits in specific tests of motor learning and spatial working memory (PubMed:16407245). Mice do not show any obvious loss of photoreceptor function in cones (PubMed:16407245). Belongs to the Ca(2+):cation antiporter (CaCA) (TC 2.A.19) family. SLC24A subfamily.