Loss of Zhf and the tightly regulated zinc-uptake system SpZrt1 in Schizosaccharomyces pombe reveals the delicacy of cellular zinc balance

Annegret Boch, Aleksandra Trampczynska, Claudia Simm, Nadine Taudte, Ute Krämer, Stephan Clemens

Research output: Contribution to journalArticleResearchpeer-review

15 Citations (Scopus)

Abstract

Zinc is an essential micronutrient, and yet it can be toxic when present in excess. Zinc acquisition and distribution are dependent on tightly controlled transport of Zn2+ ions. Schizosaccharomyces pombe represents a second eukaryotic model to study cellular metal homeostasis. In several ways its micronutrient metabolism is fundamentally different from Saccharomyces cerevisiae. We identified the first Zn2+-uptake system in S. pombe and named it SpZrt1. Knock-out strains for all three ZIP (Zrt, Irt-like protein) transporters in fission yeast were constructed. Only zrt1Δ cells were unable to grow at low Zn2+ and showed reduced 65Zn 2+ uptake. Elemental profiles revealed a strong decrease in zinc accumulation. Cd2+ ions inhibited uptake but Fe2+ or Mn2+ did not. Both mRNA abundance and protein amount are tightly regulated. Zrt1 activity is rapidly shut down upon transfer of zinc-deficient cells to zinc-replete conditions. In cells lacking Zhf, a transporter mediating endoplasmic reticulum storage of zinc, this response is about 100-fold more sensitive. Thus, removal of excess of zinc from the cytosol is largely Zhf dependent. Moreover, cells deficient for both transporters are no longer able to adjust to changing external Zn2+ concentrations. Optimal growth is restricted to a narrow range of Zn2+ concentrations, illustrating the fine balance between micronutrient deficiency and toxicity.

Original languageEnglish
Pages (from-to)883-896
Number of pages14
JournalFEMS Yeast Research
Volume8
Issue number6
DOIs
Publication statusPublished - 1 Sep 2008
Externally publishedYes

Keywords

  • Fission yeast
  • Metal homeostasis
  • Zinc transport
  • Zinc uptake

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