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      Peroxiredoxin chaperone activity is critical for protein homeostasis in zinc-deficient yeast.

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          Abstract

          Zinc is required for the folding and function of many proteins. In Saccharomyces cerevisiae, homeostatic and adaptive responses to zinc deficiency are regulated by the Zap1 transcription factor. One Zap1 target gene encodes the Tsa1 peroxiredoxin, a protein with both peroxidase and protein chaperone activities. Consistent with its regulation, Tsa1 is critical for growth under low zinc conditions. We previously showed that Tsa1's peroxidase function decreases the oxidative stress that occurs in zinc deficiency. In this report, we show that Tsa1 chaperone, and not peroxidase, activity is the more critical function in zinc-deficient cells. Mutations restoring growth to zinc-deficient tsa1 cells inactivated TRR1, encoding thioredoxin reductase. Because Trr1 is required for oxidative stress tolerance, this result implicated the Tsa1 chaperone function in tolerance to zinc deficiency. Consistent with this hypothesis, the tsa1Δ zinc requirement was complemented by a Tsa1 mutant allele that retained only chaperone function. Additionally, growth of tsa1Δ was also restored by overexpression of holdase chaperones Hsp26 and Hsp42, which lack peroxidase activity, and the Tsa1 paralog Tsa2 contributed to suppression by trr1Δ, even though trr1Δ inactivates Tsa2 peroxidase activity. The essentiality of the Tsa1 chaperone suggested that zinc-deficient cells experience a crisis of disrupted protein folding. Consistent with this model, assays of protein homeostasis suggested that zinc-limited tsa1Δ mutants accumulated unfolded proteins and induced a corresponding stress response. These observations demonstrate a clear physiological role for a peroxiredoxin chaperone and reveal a novel and unexpected role for protein homeostasis in tolerating metal deficiency.

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          Author and article information

          Journal
          J. Biol. Chem.
          The Journal of biological chemistry
          1083-351X
          0021-9258
          Oct 25 2013
          : 288
          : 43
          Affiliations
          [1 ] From the Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706 and.
          Article
          M113.512384
          10.1074/jbc.M113.512384
          3829442
          24022485
          c4f34dc4-2772-4234-b4d7-05311b460145
          History

          Molecular Chaperone,Peroxiredoxin,Protein Folding,Yeast,Zinc

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