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Activation of the Saccharomyces cerevisiae filamentation/invasion pathway by osmotic stress in high-osmolarity glycogen pathway mutantsMitogen-activated protein kinase (MAPK) cascades are frequently used signal transduction mechanisms in eukaryotes. Of the five MAPK cascades in Saccharomyces cerevisiae, the high-osmolarity glycerol response (HOG) pathway functions to sense and respond to hypertonic stress. We utilized a partial loss-of-function mutant in the HOG pathway, pbs2-3, in a high-copy suppressor screen to identify proteins that modulate growth on high-osmolarity media. Three high-copy suppressors of pbs2-3 osmosensitivity were identified: MSG5, CAK1, and TRX1. Msg5p is a dual-specificity phosphatase that was previously demonstrated to dephosphorylate MAPKs in yeast. Deletions of the putative MAPK targets of Msg5p revealed that kss1delta could suppress the osmosensitivity of pbs2-3. Kss1p is phosphorylated in response to hyperosmotic shock in a pbs2-3 strain, but not in a wild-type strain nor in a pbs2-3 strain overexpressing MSG5. Both TEC1 and FRE::lacZ expressions are activated in strains lacking a functional HOG pathway during osmotic stress in a filamentation/invasion-pathway-dependent manner. Additionally, the cellular projections formed by a pbs2-3 mutant on high osmolarity are absent in strains lacking KSS1 or STE7. These data suggest that the loss of filamentation/invasion pathway repression contributes to the HOG mutant phenotype.
Document ID
20040141783
Document Type
Reprint (Version printed in journal)
Authors
Davenport, K. D. (Rice University Houston, Texas 77005-1892, United States)
Williams, K. E.
Ullmann, B. D.
Gustin, M. C.
McIntire, L. V.
Date Acquired
August 22, 2013
Publication Date
November 1, 1999
Publication Information
Publication: Genetics
Volume: 153
Issue: 3
ISSN: 0016-6731
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: GMO-83262-7
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Cell Biology