Inhibition of phosphoglucomutase activity by lithium alters cellular calcium homeostasis and signaling in Saccharomyces cerevisiae

Péter Csutora, András Strassz, Ferenc Boldizsár, Péter Németh, Katalin Sipos, David P. Aiello, David M. Bedwell, Attila Miseta

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16 Citations (Scopus)

Abstract

Phosphoglucomutase is a key enzyme of glucose metabolism that interconverts glucose-1-phosphate and glucose-6-phosphate. Loss of the major isoform of phosphoglucomutase in Saccharomyces cerevisiae results in a significant increase in the cellular glucose-1-phosphate-to-glucose-6-phosphate ratio when cells are grown in medium containing galactose as carbon source. This imbalance in glucose metabolites was recently shown to also cause a six- to ninefold increase in cellular Ca2+ accumulation. We found that Li+ inhibition of phosphoglucomutase causes a similar elevation of total cellular Ca2+ and an increase in 45Ca2+ uptake in a wild-type yeast strain grown in medium containing galactose, but not glucose, as sole carbon source. Li+ treatment also reduced the transient elevation of cytosolic Ca2+ response that is triggered by exposure to external CaCl2 or by the addition of galactose to yeast cells starved of a carbon source. Finally, we found that the Ca2+ overaccumulation induced by Li+ exposure was significantly reduced in a strain lacking the vacuolar Ca2+-ATPase Pmc1p. These observations suggest that Li+ inhibition of phosphoglucomutase results in an increased glucose-1-phosphate-to-glucose-6-phosphate ratio, which results in an accelerated rate of vacuolar Ca2+ uptake via the Ca 2+-ATPase Pmc1p.

Original languageEnglish
Pages (from-to)C58-C67
JournalAmerican Journal of Physiology - Cell Physiology
Volume289
Issue number1 58-1
DOIs
Publication statusPublished - Jul 1 2005

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Keywords

  • Calcium influx
  • Calcium signal
  • Galactose
  • Glucose phosphate

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

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