Characterization of the osmotic-stress response in Saccharomyces cerevisiae: osmotic stress and glucose repression regulate glycerol-3-phosphate dehydrogenase independently

Curr Genet. 1994 Jan;25(1):12-8. doi: 10.1007/BF00712960.

Abstract

Micro-organisms have developed systems to adapt to sudden changes in the environment. Here we describe the response of the yeast Saccharomyces cerevisiae to osmotic stress. A drop in the water activity (aw) of the medium following the addition of NaCl led to an immediate shrinkage of the cells. During the 2 h following the osmotic shock the cells partially restored their cell volume. This process depended on active protein synthesis. During the recovery period the cells accumulated glycerol intracellularly as a compatible solute and very little glycerol was leaking out of the cell. We have investigated in more detail the enzymes of glycerol metabolism and found that only the cytoplasmic glycerol-3-phosphate dehydrogenase was strongly induced. The level of induction was dependent on the yeast strain used and the degree of osmotic stress. The synthesis of cytoplasmic glycerol-3-phosphate dehydrogenase is also regulated by glucose repression. Using mutants defective in glucose repression (hxk2 delta), or derepression (snf1 delta), and with invertase as a marker enzyme, we show that glucose repression and the osmotic-stress response system regulate glycerol-3-phosphate dehydrogenase synthesis independently. We infer that specific control mechanisms sense the osmotic situation of the cell and induce responses such as the production and retention of glycerol.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Enzyme Induction
  • Genes, Fungal
  • Glucose / pharmacology
  • Glycerol / metabolism
  • Glycerolphosphate Dehydrogenase / biosynthesis*
  • Glycerolphosphate Dehydrogenase / genetics
  • Mutation
  • Osmotic Pressure
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*

Substances

  • Glycerolphosphate Dehydrogenase
  • Glucose
  • Glycerol