Selective electrodiffusion of zinc ions in a Zrt-, Irt-like protein, ZIPB

Wei Lin, Jin Chai, James Love, Dax Fu

Research output: Contribution to journalArticle

54 Scopus citations

Abstract

All living cells need zinc ions to support cell growth. Zrt-, Irt-like proteins (ZIPs) represent a major route for entry of zinc ions into cells, but how ZIPs promote zinc uptake has been unclear. Here we report the molecular characterization of ZIPB from Bordetella bronchiseptica, the first ZIP homolog to be purified and functionally reconstituted into proteoliposomes. Zinc flux through ZIPB was found to be nonsaturable and electrogenic, yielding membrane potentials as predicted by the Nernst equation. Conversely, membrane potentials drove zinc fluxes with a linear voltage-flux relationship. Direct measurements of metal uptake by inductively coupled plasma mass spectroscopy demonstrated that ZIPB is selective for two group 12 transition metal ions, Zn2+ and Cd2+, whereas rejecting transition metal ions in groups 7 through 11. Our results provide the molecular basis for cellular zinc acquisition by a zinc-selective channel that exploits in vivo zinc concentration gradients to move zinc ions into the cytoplasm.

Original languageEnglish (US)
Pages (from-to)39013-39020
Number of pages8
JournalJournal of Biological Chemistry
Volume285
Issue number50
DOIs
Publication statusPublished - Dec 10 2010

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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