A Downshift in Temperature Activates the High Osmolarity Glycerol (HOG) Pathway, Which Determines Freeze Tolerance in Saccharomyces cerevisiae
| Autor: | Francisca Randez-Gil, Sonia Rodríguez-Vargas, Jose Antonio Prieto, Joaquin Panadero, Claudia Pallotti |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Glycerol
Osmotic stress Saccharomyces cerevisiae Proteins Osmotic shock Blotting Western Saccharomyces cerevisiae Active Transport Cell Nucleus Biochemistry Fungal Proteins chemistry.chemical_compound Species Specificity Freezing Membrane fluidity Dimethyl Sulfoxide Thermosensing Phosphorylation Molecular Biology Mitogen-Activated Protein Kinase Kinases Fungal protein biology Osmolar Concentration Intracellular Signaling Peptides and Proteins Temperature HOG pathway Wild type Membrane Proteins RNA Fungal Cell Biology Blotting Northern biology.organism_classification Trehalose Gene regulation Cell biology DNA-Binding Proteins Microscopy Fluorescence chemistry RNA Mitogen-Activated Protein Kinases Protein Kinases Cold stress Plasmids |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 0021-9258 |
| Popis: | The molecular mechanisms that enable yeast cells to detect and transmit cold signals and their physiological significance in the adaptive response to low temperatures are unknown. Here, we have demonstrated that the MAPK Hog1p is specifically activated in response to cold. Phosphorylation of Hog1p was dependent on Pbs2p, the MAPK kinase (MAPKK) of the high osmolarity glycerol (HOG) pathway, and Ssk1p, the response regulator of the two-component system Sln1p-Ypd1p. However, Sho1p was not required. Interestingly, phosphorylation of Hog1p was stimulated at 30°C in cells exposed to the membrane rigidifier agent dimethyl sulfoxide. Moreover, Hog1p activation occurred specifically through the Sln1 branch. This suggests that Sln1p monitors changes in membrane fluidity caused by cold. Quite remarkably, activation of Hog1p at low temperatures affected the transcriptional response to cold shock. Indeed, the absence of Hog1p impaired the cold-instigated expression of genes for trehalose- and glycerol-synthesizing enzymes and small chaperones. Moreover, a downward transfer to 12 or 4°C stimulated the overproduction of glycerol in a Hog1p-dependent manner. However, hog1Δ mutant cells showed no growth defects at 12°C as compared with the wild type. On the contrary, deletion of HOG1 or GPD1 decreased tolerance to freezing of wildtype cells preincubated at a low temperature, whereas no differences could be detected in cells shifted directly from 30 to -20°C. Thus, exposure to low temperatures triggered a Hog1p-dependent accumulation of glycerol, which is essential for freeze protection. © 2006 by The American Society for Biochemistry and Molecular Biology, Inc. |
| Databáze: | OpenAIRE |
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