May play a role in polarized cells by carrying out serosal-to-mucosal zinc transport (PubMed:15322118). Seems to play a central role in controlling organismal zinc status (PubMed:15322118). Could regulate the BMP/TGF-beta (bone morphogenetic protein/transforming growth factor-beta) signaling pathway and modulates extracellular matrix (ECM) proteins of the sclera (By similarity). Plays a role in eye development (By similarity). Expressed in all stages of eye development and primarily in the sclera and several layers of the retina, including the inner segment, outer plexiform layer and ganglion cell layer. Expressed at 10 dpc, postnatal day P0, P13 and adult. Glycosylated. Methylated at His-371 by METTL9. Belongs to the ZIP transporter (TC 2.A.5) family.