Zinc ion:proton antiporter that could function at the plasma membrane mediating zinc efflux from cells against its electrochemical gradient protecting them from intracellular zinc accumulation and toxicity (PubMed:31471319, PubMed:33996761, PubMed:39422023, PubMed:39111308, PubMed:39390258). Alternatively, could prevent the transport to the plasma membrane of CACNB2, the L-type calcium channels regulatory subunit, through a yet to be defined mechanism. By modulating the expression of these channels at the plasma membrane, could prevent calcium and zinc influx into cells. By the same mechanism, could also prevent L-type calcium channels-mediated heavy metal influx into cells (By similarity). In some cells, could also function as a zinc ion:proton antiporter mediating zinc entry into the lumen of cytoplasmic vesicles. In macrophages, can increase zinc ions concentration into the lumen of cytoplasmic vesicles containing engulfed bacteria and could help inactivate them (PubMed:32441444). Forms a complex with TMC6/EVER1 and TMC8/EVER2 at the ER membrane of keratynocytes which facilitates zinc uptake into the ER (PubMed:18158319). Down-regulates the activity of transcription factors induced by zinc and cytokines (PubMed:18158319). Also functions as a copper transporter, facilitating the entry of copper into cells, which is crucial for copper-induced cell death (cuproptosis) (PubMed:39111308). Acts as a Zn(2+)/Ca(2+) exchanger, exporting zinc in exchange for calcium influx (PubMed:38669333). {ECO:0000250|UniProtKB:Q62720, ECO:0000269|PubMed:18158319, ECO:0000269|PubMed:31471319, ECO:0000269|PubMed:32441444, ECO:0000269|PubMed:33996761, ECO:0000269|PubMed:38669333, ECO:0000269|PubMed:39111308, ECO:0000269|PubMed:39390258, ECO:0000269|PubMed:39422023}. This is the function of Ensembl gene identifier ENSG00000170385 (SLC30A1, solute carrier family 30 member 1).