title: Oxidant-specific folding of Yap1p regulates both transcriptional activation and nuclear localization.
abstract: The yeast transcriptional regulator Yap1p is a key determinant in oxidative stress resistance. This protein is found in the cytoplasm under non-stressed conditions but rapidly accumulates in the nucleus following oxidant exposure. There it activates transcription of genes encoding antioxidants that return the redox balance of the cell to an acceptable range. Yap1p localization to the nucleus requires the oxidant-specific formation of disulfide bonds in the N-terminal cysteine-rich domain (N-CRD) and/or the C-terminal cysteine-rich domain (C-CRD). H(2)O(2) exposure triggers the formation of two interdomain disulfide bonds between the N-and C-CRDs. This dually disulfide-bonded structure has been argued to mask the nuclear export signal in the C-CRD that would otherwise prevent Yap1p nuclear accumulation. The C-CRD is required for wild-type H(2)O(2) tolerance but dispensable for resistance to diamide. The Saccharomyces cerevisiae TRX2 gene, encoding a thioredoxin protein, cannot be induced by H(2)O(2) in the presence of various mutant forms of Yap1p lacking the normally functioning C-CRD. In this work, we demonstrate that the proper folding of Yap1p in the presence of H(2)O(2) is required for recruitment of the mediator component Rox3p to the TRX2 promoter in addition to the nuclear accumulation of Yap1p during stress by this oxidant. These data demonstrate that the dually disulfide-bonded Yap1p N- and C-CRDs form a bifunctional protein domain controlling both nuclear localization and transcriptional activation.
authors.affiliation: Department of Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Kailash
authors.initials: K
authors.lastname: Gulshan
authors.forename: Sherry A
authors.initials: SA
authors.lastname: Rovinsky
authors.forename: Sean T
authors.initials: ST
authors.lastname: Coleman
authors.forename: W Scott
authors.initials: WS
authors.lastname: Moye-Rowley
mesh_terms: D001665:Binding Sites; D002467:Cell Nucleus / Q000737:chemistry*; D003545:Cysteine / Q000032:analysis; D003593:Cytoplasm / Q000737:chemistry; D004247:DNA / Q000378:metabolism; D018983:DNA Footprinting; D003850:Deoxyribonuclease I; D004220:Disulfides / Q000737:chemistry; D017353:Gene Deletion; D015870:Gene Expression / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D056892:Mediator Complex; D008565:Membrane Proteins / Q000235:genetics; D016296:Mutagenesis; D016877:Oxidants / Q000494:pharmacology*; D018384:Oxidative Stress; D010446:Peptide Fragments / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics; D017510:Protein Folding; D012319:RNA Polymerase II / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D013329:Structure-Activity Relationship; D013879:Thioredoxins / Q000235:genetics; D014157:Transcription Factors / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic / Q000502:physiology*
chemical_list: D004220:Disulfides; D056892:Mediator Complex; D008565:Membrane Proteins; D016877:Oxidants; D010446:Peptide Fragments; C103856:ROX3 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C516110:TRX2 protein, S cerevisiae; D014157:Transcription Factors; C086677:YAP1 protein, S cerevisiae; D013879:Thioredoxins; D004247:DNA; D006861:Hydrogen Peroxide; D012319:RNA Polymerase II; D003850:Deoxyribonuclease I; D003545:Cysteine