Ethanol induces calcium influx via the Cch1-Mid1 transporter in Saccharomyces cerevisiae.
Yeast suffers from a variety of environmental stresses, such as osmotic pressure and ethanol produced during fermentation. Since calcium ions are protective for high concentrations of ethanol, we investigated whether Ca(2+) flux occurs in response to ethanol stress. We find that exposure of yeast to ethanol induces a rise in the cytoplasmic concentration of Ca(2+). The response is enhanced in cells shifted to high-osmotic media containing proline, galactose, sorbitol, or mannitol. Suspension of cells in proline and galactose-containing media increases the Ca(2+) levels in the cytoplasm independent of ethanol exposure. The enhanced ability for ethanol to induce Ca(2+) flux after the hypertonic shift is transient, decreasing rapidly over a period of seconds to minutes. There is partial recovery of the response after zymolyase treatment, suggesting that cell wall integrity affects the ethanol-induced Ca(2+) flux. Acetate inhibits the Ca(2+) accumulation elicited by the ethanol/osmotic stress. The Ca(2+) flux is primarily via the Cch1 Ca(2+) influx channel because strains carrying deletions of the cch1 and mid1 genes show greater than 90% reduction in Ca(2+) flux. Furthermore, a functional Cch1 channel reduced growth inhibition by ethanol.
Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno, 89557, USA. wcourchesne@medicine.nevada.edu
William E
WE
Courchesne
Christopher
C
Vlasek
Rachel
R
Klukovich
Sara
S
Coffee
D019342:Acetic Acid / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D002473:Cell Wall / Q000378:metabolism; D003470:Culture Media; D003593:Cytoplasm / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology*; D017353:Gene Deletion; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D009997:Osmotic Pressure; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
C108765:CCH1 protein, S cerevisiae; D015220:Calcium Channels; D003470:Culture Media; C090463:MID1 protein, S cerevisiae; D008562:Membrane Glycoproteins; D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol; D019342:Acetic Acid; D002118:Calcium