Together with SLC30A6 forms a functional proton-coupled zinc ion antiporter mediating zinc entry into the lumen of organelles along the secretory pathway (PubMed:11904301, PubMed:15525635, PubMed:15994300, PubMed:19366695, PubMed:22529353). By contributing to zinc ion homeostasis within the early secretory pathway, regulates the activation and folding of enzymes like alkaline phosphatases and enzymes involved in phosphatidylinositol glycan anchor biosynthesis (PubMed:15525635, PubMed:15994300, PubMed:16636052, PubMed:35525268). Through the transport of zinc into secretory granules of pancreatic beta-cells, plays an important role in the storage and secretion of insulin (PubMed:11904301). ; [Isoform 2]: Zinc ion:proton antiporter mediating influx and efflux of zinc at the plasma membrane.
