PBS2, a yeast gene encoding a putative protein kinase, interacts with the RAS2 pathway and affects osmotic sensitivity of Saccharomyces cerevisiae

J Gen Microbiol. 1992 Nov;138(11):2425-32. doi: 10.1099/00221287-138-11-2425.


The yeast gene PBS2 encodes a presumed protein kinase. The gene is essential for manifestation of resistance to the antibiotic polymyxin B. Deletion of PBS2 enables a ras2-530 null mutant to grow on nonfermentable carbon sources; overexpression of PBS2+ enhances viability of a RAS2Val19 mutant. Overexpression of PBS2+ also diminishes cellular response to mating pheromone MF alpha. These results suggest that the PBS2 and RAS2 genes affect a common pathway that may communicate with the pheromone response pathway. In addition, disruption of PBS2 renders cells sensitive to high osmolarity: exposure to 0.9 M-NaCl causes growth arrest, appearance of bizarre morphological forms, and eventual death. A mutation suppressing pbs2 deletion has been found. That mutation restores full polymyxin B resistance but only partially corrects the osmotic sensitivity defect. These observations indicate that PBS2 is involved in diverse physiological pathways in yeast.

MeSH terms

  • Carbon / metabolism
  • Drug Resistance, Microbial
  • Gene Deletion
  • Genes, Fungal / genetics*
  • Osmotic Fragility / genetics*
  • Pheromones / pharmacology
  • Polymyxin B / pharmacology
  • Protein Kinases / genetics*
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics*
  • Signal Transduction*
  • Sodium Chloride / pharmacology
  • Suppression, Genetic


  • Pheromones
  • Sodium Chloride
  • Carbon
  • Protein Kinases
  • Polymyxin B