title: Non-enzymatic roles for the URE2 glutathione S-transferase in the response of Saccharomyces cerevisiae to arsenic.
abstract: The response of Saccharomyces cerevisiae to arsenic involves a large ensemble of genes, many of which are associated with glutathione-related metabolism. The role of the glutathione S-transferase (GST) product of the URE2 gene involved in resistance of S. cerevisiae to a broad range of heavy metals was investigated. Glutathione peroxidase activity, previously reported for the Ure2p protein, was unaffected in cell-free extracts of an ure2Δ mutant of S. cerevisiae. Glutathione levels in the ure2Δ mutant were lowered about threefold compared to the isogenic wild-type strain but, as in the wild-type strain, increased 2-2.5-fold upon addition of either arsenate (As(V)) or arsenite (As(III)). However, lack of URE2 specifically caused sensitivity to arsenite but not to arsenate. The protective role of URE2 against arsenite depended solely on the GST-encoding 3'-end portion of the gene. The nitrogen source used for growth was suggested to be an important determinant of arsenite toxicity, in keeping with non-enzymatic roles of the URE2 gene product in GATA-type regulation.
authors.affiliation: Faculty of Biology, Department of General and Applied Microbiology, Sofia University St. Kliment Ohridski, 1164, Sofia, Bulgaria.
authors.forename: Tatina T
authors.initials: TT
authors.lastname: Todorova
authors.forename: Anna V
authors.initials: AV
authors.lastname: Kujumdzieva
authors.forename: Stéphane
authors.initials: S
authors.lastname: Vuilleumier
mesh_terms: D001149:Arsenates / Q000378:metabolism; D001151:Arsenic / Q000378:metabolism*; D018053:Arsenites / Q000378:metabolism; D005816:Genetic Complementation Test; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism*; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D011328:Prions / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D001149:Arsenates; D018053:Arsenites; D011328:Prions; D029701:Saccharomyces cerevisiae Proteins; D005979:Glutathione Peroxidase; C067020:URE2 protein, S cerevisiae; D005982:Glutathione Transferase; D005978:Glutathione; C015001:arsenite; D001151:Arsenic; C025657:arsenic acid