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Metal transport, subcellular localization, and tissue distribution of Zip8, a Zip14 homologue
Author(s) -
Wang Chia-Yu,
Jenkitkasemwong Supak,
Sparkman Brian K.,
Shawki Ali,
Mackenzie Bryan,
Knutson Mitchell
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.641.32
Subject(s) - chemistry , hek 293 cells , metal , complementary dna , rna , zinc , transporter , biochemistry , microbiology and biotechnology , biophysics , biology , gene , organic chemistry
We have previously demonstrated that Zip14, a member of the ZIP family of metal‐ion transport proteins, can transport zinc and iron into cells. The aim of the present study was to investigate metal transport, subcellular localization, and tissue distribution of Zip8, the most closely related protein to Zip14. Similar to Zip14, we found that transient transfection of HEK 293T cells with Zip8 cDNA enhanced the cellular uptake of iron and zinc, and that Zip8 is detectable at the cell surface as a transmembrane glycoprotein. Expression of Zip8 in RNA‐injected Xenopus oocytes stimulated between 15 and 150‐fold over control the uptake of 109 Cd 2+ , 57 Co 2+ , 55 Fe 2+ , and 65 Zn 2+ , but not 64 Cu (I or II). Zip8‐mediated transport of 55 Fe 2+ ( K 0.5 ≈ 0.5 μM) was maximal at pH ≈ 7.5. Quantitative RT‐PCR analysis of RNA from various human tissues revealed that Zip8 is most abundantly expressed in lung and placenta, whereas Zip14 is most abundant in liver and heart. We conclude that, although Zip8 and Zip14 have similar metal transport profiles, their distinct tissue distributions suggest that they serve nonredundant functions in metal metabolism. Funded by NIH. Grant Funding Source : NIH