Abstract
Very little is known about how cellular osmosensors monitor changes in osmolarity of the environment. Here, we report that in yeast, Sln1 osmosensor histidine kinase monitors changes in turgor pressures. Reductions in turgor caused by either hyperosmotic stress, nystatin, or removal of cell wall activate MAPK Hog1 specifically through the SLN1 branch, but not through the SHO1 branch of the high osmolarity glycerol pathway. The integrity of the periplasmic region of Sln1 was essential for its sensor function. We found that activity of the plant histidine kinase cytokinin response 1 (Cre1) is also regulated by changes in turgor pressure, in a manner identical to that of Sln1, in the presence of cytokinin. We propose that Sln1 and Cre1 are turgor sensors, and that similar turgor-sensing mechanisms might regulate hyperosmotic stress responses both in yeast and plants.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Arabidopsis Proteins / metabolism*
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Cell Wall / metabolism
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Cytokinins / metabolism
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Cytokinins / pharmacology
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Glycerol / metabolism
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Intracellular Signaling Peptides and Proteins
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Intracranial Pressure / physiology*
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Mitogen-Activated Protein Kinases / metabolism
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Nystatin / pharmacology
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Osmotic Pressure
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Protein Kinases / metabolism*
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Receptors, Cell Surface / metabolism*
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Water-Electrolyte Balance / physiology*
Substances
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Arabidopsis Proteins
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Cytokinins
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Intracellular Signaling Peptides and Proteins
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Receptors, Cell Surface
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Saccharomyces cerevisiae Proteins
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Nystatin
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Protein Kinases
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HOG1 protein, S cerevisiae
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Mitogen-Activated Protein Kinases
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SLN1 protein, S cerevisiae
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WOL protein, Arabidopsis
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Glycerol