The high osmotic response and cell wall integrity pathways cooperate to regulate transcriptional responses to zymolyase-induced cell wall stress in Saccharomyces cerevisiae.
The adaptation of Saccharomyces cerevisiae to situations in which cell wall integrity is seriously compromised mainly involves the cell wall integrity (CWI) pathway. However, in a recent work ( Bermejo, C., Rodriguez, E., García, R., Rodríguez-Peña, J. M., Rodríguez de la Concepción, M. L., Rivas, C., Arias, P., Nombela, C., Posas, F., and Arroyo, J. (2008) Mol. Biol. Cell 19, 1113-1124 ) we have demonstrated the co-participation of the high osmotic response (HOG) pathway to ensure yeast survival to cell wall stress mediated by zymolyase, which hydrolyzes the beta-1,3 glucan network. Here we have characterized the role of both pathways in the regulation of the overall yeast transcriptional responses to zymolyase treatment using whole genome expression profiling. A main group of yeast genes is dependent on both MAPKs, Slt2 and Hog1, for their induction. The transcriptional activation of these genes depends on the MAPKKK Bck1, the transcription factor Rlm1, and elements of the sho1 branch of the HOG pathway, but not on the sensors of the CWI pathway. A second group of genes is dependent on Slt2 but not Hog1 or Pbs2. However, the induction of these genes is dependent on upstream elements of the HOG pathway such as Sho1, Ste50, and Ste11, in accordance with a sequential activation of the HOG and CWI pathways. Zymolyase also promotes an osmotic-like transcriptional response with the activation of a group of genes dependent on elements of the Sho1 branch of HOG pathway but not on Slt2, with the induction of many of them dependent on Msn2/4. Additionally, in the absence of Hog1, zymolyase induces an alternative response related to mating and filamentation as a consequence of the cross-talk between these pathways and the HOG pathway. Finally, in the absence of Slt2, zymolyase increases the induction of genes associated with osmotic adaptation with respect to the wild type, suggesting an inhibitory effect of the CWI pathway over the HOG pathway. These studies clearly reveal the complexity of the signal transduction machinery responsible for regulating yeast adaptation responses to cell wall stress.
García
Raúl
R
Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain.
Rodríguez-Peña
Jose M
JM
Bermejo
Clara
C
Nombela
César
C
Arroyo
Javier
J
D002473:Cell Wall / Q000378:metabolism*; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism*; D026161:MADS Domain Proteins; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D009997:Osmotic Pressure; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
D026161:MADS Domain Proteins; C095725:RLM1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C037833:zymolyase; C072075:BCK1 protein, S cerevisiae; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae; D020929:Mitogen-Activated Protein Kinase Kinases; D006867:Hydrolases