Protein Kinase A Regulates Constitutive Expression of Small Heat-Shock Genes in an Msn2/4p-Independent and Hsf1p-Dependent Manner in Saccharomyces cerevisiae

DOI PDF 被引用文献2件
  • Scott B Ferguson
    Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059
  • Erik S Anderson
    Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059
  • Robyn B Harshaw
    Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059
  • Tim Thate
    Howard Hughes Medical Institute and the Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2185
  • Nancy L Craig
    Howard Hughes Medical Institute and the Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2185
  • Hillary C M Nelson
    Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6059

抄録

<jats:title>Abstract</jats:title> <jats:p>Hsf1p, the heat-shock transcription factor from Saccharomyces cerevisiae, has a low level of constitutive transcriptional activity and is kept in this state through negative regulation. In an effort to understand this negative regulation, we developed a novel genetic selection that detects altered expression from the HSP26 promoter. Using this reporter strain, we identified mutations and dosage compensators in the Ras/cAMP signaling pathway that decrease cAMP levels and increase expression from the HSP26 promoter. In yeast, low cAMP levels reduce the catalytic activity of the cAMP-dependent kinase PKA. Previous studies had proposed that the stress response transcription factors Msn2p/4p, but not Hsf1p, are repressed by PKA. However, we found that reduction or elimination of PKA activity strongly derepresses transcription of the small heat-shock genes HSP26 and HSP12, even in the absence of MSN2/4. In a strain deleted for MSN2/4 and the PKA catalytic subunits, expression of HSP12 and HSP26 depends on HSF1 expression. Our findings indicate that Hsf1p functions downstream of PKA and suggest that PKA might be involved in negative regulation of Hsf1p activity. These results represent a major change in our understanding of how PKA signaling influences the heat-shock response and heat-shock protein expression.</jats:p>

収録刊行物

  • Genetics

    Genetics 169 (3), 1203-1214, 2005-03-01

    Oxford University Press (OUP)

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