Glucose starvation results in UDP-glucose deficiency and inactivation of glycogen synthase

Arch Biochem Biophys. 2004 May 15;425(2):242-8. doi: 10.1016/j.abb.2004.03.003.

Abstract

The effects of glucose starvation on glycogen synthase (GS) activity and protein expression were investigated. Fibroblasts were cultured in medium supplemented with either glucose or pyruvate. Pyruvate-cultured cells exhibited UDP-glucose contents that amounted to approximately 10% of those in cells cultured with glucose. GS activity, protein and mRNA amounts in pyruvate-cultured cells were decreased to approximately 35, 60, and 60%, respectively, of values in glucose-cultured cells. Incubation of extracts from glucose-cultured cells with radioactive UDP-glucose resulted in substantial binding of ligand to immunoprecipitated GS. However, binding in immunoprecipitates from pyruvate-cultured cells was decreased to approximately 25% of values in glucose-cultured cells. These data indicate that glucose starvation and the subsequent depletion of UDP-glucose result in: (1) inactivation of GS, owing to a decrease in its ability to bind UDP-glucose, and (2) decreased amount of GS protein, owing to a decrease in the levels of GS mRNA.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Cricetinae
  • Cricetulus
  • Enzyme Activation
  • Enzyme Inhibitors
  • Fibroblasts / metabolism*
  • Glucose / deficiency*
  • Glycogen Synthase / metabolism*
  • Lung / metabolism
  • Mutagenesis, Site-Directed
  • Mutation
  • Starvation / metabolism
  • Uridine Diphosphate Glucose / deficiency*

Substances

  • Enzyme Inhibitors
  • Glycogen Synthase
  • Glucose
  • Uridine Diphosphate Glucose