title: Arsenic Directly Binds to and Activates the Yeast AP-1-Like Transcription Factor Yap8.
abstract: The AP-1-like transcription factor Yap8 is critical for arsenic tolerance in the yeast Saccharomyces cerevisiae. However, the mechanism by which Yap8 senses the presence of arsenic and activates transcription of detoxification genes is unknown. Here we demonstrate that Yap8 directly binds to trivalent arsenite [As(III)] in vitro and in vivo and that approximately one As(III) molecule is bound per molecule of Yap8. As(III) is coordinated by three sulfur atoms in purified Yap8, and our genetic and biochemical data identify the cysteine residues that form the binding site as Cys132, Cys137, and Cys274. As(III) binding by Yap8 does not require an additional yeast protein, and Yap8 is regulated neither at the level of localization nor at the level of DNA binding. Instead, our data are consistent with a model in which a DNA-bound form of Yap8 acts directly as an As(III) sensor. Binding of As(III) to Yap8 triggers a conformational change that in turn brings about a transcriptional response. Thus, As(III) binding to Yap8 acts as a molecular switch that converts inactive Yap8 into an active transcriptional regulator. This is the first report to demonstrate how a eukaryotic protein couples arsenic sensing to transcriptional activation.
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden.
authors.forename: Nallani Vijay
authors.initials: NV
authors.lastname: Kumar
authors.affiliation: Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA.
authors.forename: Jitesh K
authors.initials: JK
authors.lastname: Pillai
authors.affiliation: Department of Biochemistry and Molecular Biology and Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan, USA.
authors.forename: Swati
authors.initials: S
authors.lastname: Rawat
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden.
authors.forename: Carlos
authors.initials: C
authors.lastname: Solano
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden.
authors.forename: Abhay
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden.
authors.forename: Morten
authors.initials: M
authors.lastname: Grøtli
authors.affiliation: Department of Biochemistry and Molecular Biology and Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan, USA.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Stemmler
authors.affiliation: Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA.
authors.forename: Barry P
authors.initials: BP
authors.lastname: Rosen
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden markus.tamas@cmb.gu.se.
authors.forename: Markus J
authors.initials: MJ
authors.lastname: Tamás
mesh_terms: D053502:Arsenate Reductases / Q000235:genetics; D001151:Arsenic / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D026901:Membrane Transport Proteins / Q000235:genetics; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: C109281:ACR3 protein, S cerevisiae; C494591:ARR1 protein, S cerevisiae; D050976:Basic-Leucine Zipper Transcription Factors; D004271:DNA, Fungal; D026901:Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; D018808:Transcription Factor AP-1; C506971:ARR2 protein, S cerevisiae; D053502:Arsenate Reductases; D001151:Arsenic