Abstract
Sln1p is a plasma membrane-localized two-component histidine kinase that functions as an osmotic stress sensor in Saccharomyces cerevisiae. Changes in osmotic pressure modulate Sln1p kinase activity, which, together with Ypd1p, a phosphorelay intermediate, changes the phosphorylation status of two response regulators, Ssk1p and Skn7p. Ssk1p controls the activity of the HOG1 mitogen-activated protein kinase pathway. Skn7p is a nuclearly localized transcription factor that regulates genes involved in cell wall integrity and other processes. Subcellular compartmentalization may therefore play an important role in eukaryotic two-component pathway regulation. We have studied the subcellular localization of SLN1 pathway components and find that Ypd1p is a dynamic protein with a role in shuttling the osmotic stress signal from Sln1p to Ssk1p in the cytosol and to Skn7p in the nucleus. The need to translocate the signal into different intracellular compartments contributes a spatial dimension to eukaryotic two-component pathways compared to the prototypical two-component pathways of prokaryotes.
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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Cell Nucleus / metabolism
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Cytoplasm / metabolism
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Fungal Proteins / genetics
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Fungal Proteins / metabolism*
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Genes, Reporter
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Green Fluorescent Proteins
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Intracellular Signaling Peptides and Proteins
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Luminescent Proteins / metabolism
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Microscopy, Confocal
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Models, Biological
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Osmotic Pressure
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Oxidative Stress
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Phosphorylation
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Protein Kinases / genetics
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Protein Kinases / metabolism*
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Temperature
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Transcription Factors / genetics
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Transcription Factors / metabolism*
Substances
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DNA-Binding Proteins
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Fungal Proteins
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Intracellular Signaling Peptides and Proteins
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Luminescent Proteins
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Recombinant Fusion Proteins
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SKN7 protein, S cerevisiae
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SSK1 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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Transcription Factors
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Green Fluorescent Proteins
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Protein Kinases
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YPD1 protein, S cerevisiae
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SLN1 protein, S cerevisiae