title: The ZIP7 gene (Slc39a7) encodes a zinc transporter involved in zinc homeostasis of the Golgi apparatus.
abstract: It has been suggested that ZIP7 (Ke4, Slc39a7) belongs to the ZIP family of zinc transporters. Transient expression of the V5-tagged human ZIP7 fusion protein in CHO cells led to elevation of the cytoplasmic zinc level. However, the precise function of ZIP7 in cellular zinc homeostasis is not clear. Here we report that the ZIP7 gene is ubiquitously expressed in human and mouse tissues. The endogenous ZIP7 was associated with the Golgi apparatus and was capable of transporting zinc from the Golgi apparatus into the cytoplasm of the cell. Moreover, by using the yeast mutant strain Deltazrt3 that was defective in release of stored zinc from vacuoles, we found that ZIP7 was able to decrease the level of accumulated zinc and in the meantime to increase the nuclear/cytoplasmic labile zinc level in the ZIP7-expressing zrt3 mutant. We showed that the protein expression of ZIP7 was repressed under zinc-rich condition, whereas there were no effects of zinc on ZIP7 gene expression and intracellular localization. Neither did zinc deficiency affect the intracellular distribution of ZIP7 in mammalian cells. Our study demonstrates that ZIP7 is a functional zinc transporter that acts by transporting zinc from the Golgi apparatus to the cytoplasm of the cell.
authors.affiliation: Agricultural Research Service, United States Department of Agriculture, Western Human Nutrition Research Center, University of California at Davis, 95616, USA. lhuang@whnrc.usda.gov <lhuang@whnrc.usda.gov>
authors.forename: Liping
authors.initials: L
authors.lastname: Huang
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Kirschke
authors.forename: Yunfan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yan Yiu
authors.initials: YY
authors.lastname: Yu
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D016466:CHO Cells; D027682:Cation Transport Proteins / Q000378:metabolism / Q000502:physiology*; D002460:Cell Line; D045744:Cell Line, Tumor; D002712:Chlorides / Q000494:pharmacology; D006224:Cricetinae; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D020224:Expressed Sequence Tags; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D020014:K562 Cells; D008099:Liver / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D015363:Quinolones / Q000737:chemistry; D011993:Recombinant Fusion Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014018:Tissue Distribution; D014105:Tosyl Compounds / Q000737:chemistry; D015032:Zinc / Q000737:chemistry; D017967:Zinc Compounds / Q000494:pharmacology; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D027682:Cation Transport Proteins; D002712:Chlorides; D018076:DNA, Complementary; D008565:Membrane Proteins; D015363:Quinolones; D011993:Recombinant Fusion Proteins; D014105:Tosyl Compounds; D015032:Zinc; D017967:Zinc Compounds; D001616:beta-Galactosidase; C102227:SLC39A7 protein, human; C000589478:Slc39a7 protein, mouse; C016837:zinc chloride; C084731:zinquin