The function of ATP2B3 (ATPase plasma membrane Ca2+ transporting 3, Ensembl gene identifier ENSG00000067842) is as follows. ATP-driven Ca(2+) ion pump involved in the maintenance of basal intracellular Ca(2+) levels at the presynaptic terminals (PubMed:18029012, PubMed:22912398, PubMed:25953895, PubMed:27035656). Uses ATP as an energy source to transport cytosolic Ca(2+) ions across the plasma membrane to the extracellular compartment (PubMed:25953895, PubMed:27035656). May counter-transport protons, but the mechanism and the stoichiometry of this Ca(2+)/H(+) exchange remains to be established (By similarity). {ECO:0000250|UniProtKB:Q64568, ECO:0000269|PubMed:18029012, ECO:0000269|PubMed:22912398, ECO:0000269|PubMed:25953895, ECO:0000269|PubMed:27035656}.