Figure 2.

Zn transporter expression in the secreting epithelium of the rat prostate. Lobes of the rat prostate are illustrated on the left. On the right, a cartoon of an epithelial cell of the lateral lobe illustrates our current understanding of Zn transporter localization and Zn function. Zip2 and Zip3 are localized to the apical membrane and Zip1 is localized to the basal membrane; all function to import Zn into the cell. ZnT4, ZnT6, and ZnT7 are localized to the Golgi apparatus and ZnT2 is localized to the ER; these transporters likely function to maintain the secretory pathway. There is no known transporter for the mitochondria where high Zn levels inhibit the oxidation of citrate, providing a source for secretion.