Yeast Whi2 and Psr1-phosphatase form a complex and regulate STRE-mediated gene expression

Genes Cells. 2002 Jun;7(6):543-52. doi: 10.1046/j.1365-2443.2002.00538.x.


Background: In response to various stressful situations, including diauxic conditions, the Msn2 and Msn4 transcription factors induce STRE-mediated gene expression of many stress responsive genes in Saccharomyces cerevisiae. This is called the general stress response. The whi2 cells in the stationary phase are smaller than wild-type cells.

Results: Here we demonstrate that STRE-mediated gene expression in whi2 cells is reduced to half of that in the wild-type cells under various stress conditions. It is also delayed for several hours when the mutant cells enter the stationary phase. Using the two-hybrid system, we isolated a WHI2-interacting gene, PSR1, which is one of the redundant genes encoding plasma membrane phosphatases. whi2 and psr1 psr2 mutants had similar phenotypes, including reduced STRE-mediated gene expression, higher sensitivity to sodium ions and heat shock, and hyper-phosphorylation of Msn2. The phosphatase activity of Psr1 was necessary for the full activation of STRE-mediated gene expression. Furthermore, both Psr1 and Msn2 were co-immunoprecipitated with Whi2.

Conclusions: Thus, Whi2 and its binding partner, Psr1-phosphatase, are required for a full activation of the general stress response, possibly through the dephosphorylation of Msn2. These results may explain why stationary phase whi2 cells are small.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cyclin-Dependent Kinase 8
  • Cyclin-Dependent Kinases / metabolism
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation, Fungal / physiology*
  • Membrane Proteins
  • Phosphoprotein Phosphatases / genetics
  • Phosphoprotein Phosphatases / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Transcription Factors / metabolism
  • Yeasts


  • DNA-Binding Proteins
  • MSN2 protein, S cerevisiae
  • Membrane Proteins
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Whi2 protein, S cerevisiae
  • Cyclin-Dependent Kinase 8
  • Cyclin-Dependent Kinases
  • SSN3 protein, S cerevisiae
  • PSR2 protein, S cerevisiae
  • PSR1 protein, S cerevisiae
  • Phosphoprotein Phosphatases