Cdc37p is required for stress-induced high-osmolarity glycerol and protein kinase C mitogen-activated protein kinase pathway functionality by interaction with Hog1p and Slt2p (Mpk1p).
The yeast Saccharomyces cerevisiae utilizes rapidly responding mitogen-activated protein kinase (MAPK) signaling cascades to adapt efficiently to a changing environment. Here we report that phosphorylation of Cdc37p, an Hsp90 cochaperone, by casein kinase 2 controls the functionality of two MAPK cascades in yeast. These pathways, the high-osmolarity glycerol (HOG) pathway and the cell integrity (protein kinase C) MAPK pathway, mediate adaptive responses to high osmotic and cell wall stresses, respectively. Mutation of the phosphorylation site Ser14 in Cdc37p renders cells sensitive to osmotic stress and cell wall perturbation by calcofluor white. We found that levels of the MAPKs Hog1p and Slt2p (Mpk1p) in cells are reduced in a cdc37-S14A mutant, and consequently downstream responses mediated by Hog1p and Slt2p are compromised. Furthermore, we present evidence that Hog1p and Slt2p both interact in a complex with Cdc37p in vivo, something that has not been reported previously. The interaction of Hsp90, Slt2p, and Hog1p with Cdc37p depends on the phosphorylation status of Cdc37p. In fact, our biochemical data show that the osmosensitive phenotype of the cdc37-S14A mutant is due to the loss of the interaction between Cdc37p, Hog1p, and Hsp90. Likewise, during cell wall stress, the interaction of Slt2p with Cdc37p and Hsp90 is crucial for Slt2p-dependent downstream responses, such as the activation of the transcription factor Rlm1p. Interestingly, phosphorylated Slt2p, but not phosphorylated Hog1p, has an increased affinity for Cdc37p. Together these observations suggest that Cdc37p acts as a regulator of MAPK signaling.
Hawle
Patricija
P
Department of Biochemistry and Molecular Biology, Faculty of Science, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
Horst
Danielle
D
Bebelman
Jan Paul
JP
Yang
Xiao Xian
XX
Siderius
Marco
M
van der Vies
Saskia M
SM
D018797:Cell Cycle Proteins / Q000378:metabolism*; D002473:Cell Wall / Q000737:chemistry; D015966:Gene Expression Regulation, Fungal; D005990:Glycerol / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D026161:MADS Domain Proteins; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism*; D009997:Osmotic Pressure; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism
C513270:CDC37 protein, S cerevisiae; D018797:Cell Cycle Proteins; D018841:HSP90 Heat-Shock Proteins; D026161:MADS Domain Proteins; D018832:Molecular Chaperones; C095725:RLM1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D011493:Protein Kinase C; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae; D005990:Glycerol