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ABSTRACT: Genome-wide studies have recently revealed the unexpected complexity of the genetic response to apparently simple physiological changes. Here, we show that when yeast cells are exposed to Cd(2+), most of the sulfur assimilated by the cells is converted into glutathione, a thiol-metabolite essential for detoxification. Cells adapt to this vital metabolite requirement by modifying globally their proteome to reduce the production of abundant sulfur-rich proteins. In particular, some abundant glycolytic enzymes are replaced by sulfur-depleted isozymes. This global change in protein expression allows an overall sulfur amino acid saving of 30%. This proteomic adaptation is essentially regulated at the mRNA level. The main transcriptional activator of the sulfate assimilation pathway, Met4p, plays an essential role in this sulfur-sparing response.
Molecular Cell 05/2002; 9(4):713-23. · 14.46 Impact Factor