Weak organic acids trigger conformational changes of the yeast transcription factor War1 in vivo to elicit stress adaptation.
The Saccharomyces cerevisiae zinc cluster regulator War1 mediates an essential transcriptional and adaptive response to weak organic acid stress. Here we investigate the mechanism of War1 activation upon weak acid stress. We identified several gain-of-function WAR1 alleles mapping to the central War1 region. These mutations constitutively increase levels of the plasma membrane ABC transporter Pdr12, the main War1 target mediating stress adaptation. Functional analysis of War1 reveals that the central region and its C-terminal activation domain are required for function. Notably, the native DNA-binding and dimerization domains appear dispensable for War1 activity, because they can be replaced by a LexA DNA-binding domain. Chromatin immunoprecipitation demonstrates elevated promoter affinity of activated War1, because its PDR12 promoter association increases upon stress. Hyperactive WAR1 alleles have constitutively high PDR12 promoter association. Furthermore, fluorescence resonance energy transfer of functional CFP-War1-YFP proteins also demonstrates conformational changes of stress-activated War1 in vivo. Our results suggest a mechanism whereby War1 activation is accompanied by conformational changes enhancing promoter association, thus initiating the adaptation process.
Gregori
Christa
C
Medical University of Vienna, Max F. Perutz Laboratories, Vienna, Austria.
Schüller
Christoph
C
University of Vienna, Max F. Perutz Laboratories, A-1030 Vienna, Austria. Electronic address: Christoph.Schueller@univie.ac.at.
Frohner
Ingrid E
IE
Medical University of Vienna, Max F. Perutz Laboratories, Vienna, Austria.
Ammerer
Gustav
G
University of Vienna, Max F. Perutz Laboratories, A-1030 Vienna, Austria.
Kuchler
Karl
K
Medical University of Vienna, Max F. Perutz Laboratories, Vienna, Austria. Electronic address: karl.kuchler@meduniwien.ac.at.
D000143:Acids / Q000494:pharmacology; D000595:Amino Acid Sequence; D004271:DNA, Fungal / Q000737:chemistry; D019281:Dimerization; D031541:Fluorescence Resonance Energy Transfer; D015966:Gene Expression Regulation, Fungal; D005838:Genotype; D008954:Models, Biological; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D000143:Acids; D004271:DNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C472674:War1 protein, S cerevisiae