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Updated: Jul 1, 2026
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Growth-based Determination and Biochemical Confirmation of Genetic Requirements for Protein Degradation in Saccharomyces cerevisiae
Published on: February 16, 2015
Chromate causes sulfur starvation in yeast.
Yannick Pereira1, Gilles Lagniel, Emmanuel Godat
1Laboratoire de Biologie Intégrative, SBIGeM/iBiTec-S, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France.
Toxicological Sciences : an Official Journal of the Society of Toxicology
|September 17, 2008
Summary
Chromate exposure severely disrupts sulfur metabolism in yeast, leading to sulfur starvation and altered gene expression. Supplementing sulfate alleviates chromate toxicity by competing with chromate uptake and metabolism.
Area of Science:
- Environmental toxicology
- Cellular and molecular biology
- Biochemistry
Background:
- Chromate is a pervasive environmental pollutant with poorly understood toxicity mechanisms.
- Understanding chromate's cellular effects requires a model eukaryote system.
Purpose of the Study:
- To investigate the physiological impacts of chromate exposure on Saccharomyces cerevisiae.
- To elucidate the molecular mechanisms underlying chromate toxicity and cellular responses.
Main Methods:
- Yeast (Saccharomyces cerevisiae) was used as a eukaryote cell model.
- Analysis of sulfate assimilation, sulfur metabolite pools, and enzyme induction.
- Investigated gene regulation at the mRNA level and transcription factor dependency.
- Studied chromate uptake via sulfate transporters and competitive inhibition.
Main Results:
- Chromate exposure induced sulfur starvation by decreasing sulfate assimilation and sulfur metabolite pools.
- Enzymes in the sulfur pathway and sulfur-sparing response (e.g., Pdc6) were highly induced.
- Pdc6 induction was regulated at the mRNA level and dependent on Met32/Met4 transcriptional activation.
- Chromate uptake occurred through sulfate transporters, competitively inhibiting sulfate uptake.
- Sulfate supplementation mitigated chromate toxicity, suggesting competitive interactions.
Conclusions:
- Chromate disrupts cellular sulfur metabolism, leading to sulfur starvation and adaptive responses in yeast.
- Chromate toxicity involves competitive inhibition of sulfate uptake and potentially other metabolic steps.
- The Met32/Met4 pathway plays a crucial role in regulating the cellular response to chromate-induced sulfur depletion.
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