Protein phosphatase type 1 regulates ion homeostasis in Saccharomyces cerevisiae

Genetics. 2002 Apr;160(4):1423-37. doi: 10.1093/genetics/160.4.1423.


Protein phosphatase type 1 (PP1) is encoded by the essential gene GLC7 in Saccharomyces cerevisiae. glc7-109 (K259A, R260A) has a dominant, hyperglycogen defect and a recessive, ion and drug sensitivity. Surprisingly, the hyperglycogen phenotype is partially retained in null mutants of GAC1, GIP2, and PIG1, which encode potential glycogen-targeting subunits of Glc7. The R260A substitution in GLC7 is responsible for the dominant and recessive traits of glc7-109. Another mutation at this residue, glc7-R260P, confers only salt sensitivity, indicating that the glycogen and salt traits of glc7-109 are due to defects in distinct physiological pathways. The glc7-109 mutant is sensitive to cations, aminoglycosides, and alkaline pH and exhibits increased rates of l-leucine and 3,3'-dihexyloxacarbocyanine iodide uptake, but it is resistant to molar concentrations of sorbitol or KCl, indicating that it has normal osmoregulation. KCl suppresses the ion and drug sensitivities of the glc7-109 mutant. The CsCl sensitivity of this mutant is suppressed by recessive mutations in PMA1, which encodes the essential plasma membrane H(+)ATPase. Together, these results indicate that Glc7 regulates ion homeostasis by controlling ion transport and/or plasma membrane potential, a new role for Glc7 in budding yeast.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aminoglycosides
  • Anti-Bacterial Agents / metabolism
  • Calcineurin / metabolism
  • Cesium / metabolism
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Glycogen / metabolism
  • Hydrogen-Ion Concentration
  • Leucine / metabolism
  • Mutation
  • Phosphoprotein Phosphatases / genetics
  • Phosphoprotein Phosphatases / metabolism*
  • Potassium / metabolism
  • Proton-Translocating ATPases / genetics
  • Proton-Translocating ATPases / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Sodium Chloride / metabolism


  • Aminoglycosides
  • Anti-Bacterial Agents
  • Fungal Proteins
  • Saccharomyces cerevisiae Proteins
  • Cesium
  • Sodium Chloride
  • Glycogen
  • Calcineurin
  • Phosphoprotein Phosphatases
  • PMA1 protein, S cerevisiae
  • Proton-Translocating ATPases
  • Leucine
  • Potassium