title: Glucose starvation results in UDP-glucose deficiency and inactivation of glycogen synthase.
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.
authors.affiliation: Microbiology and Tumor Biology Center, Karolinska Institutet, Stockholm S-171 77, Sweden.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Higuita
authors.forename: Monica
authors.initials: M
authors.lastname: Thelestam
authors.forename: Abram
authors.initials: A
authors.lastname: Katz
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004789:Enzyme Activation; D004791:Enzyme Inhibitors; D005347:Fibroblasts / Q000378:metabolism*; D005947:Glucose / Q000172:deficiency*; D006006:Glycogen Synthase / Q000378:metabolism*; D008168:Lung / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D013217:Starvation / Q000378:metabolism; D014532:Uridine Diphosphate Glucose / Q000172:deficiency*
chemical_list: D004791:Enzyme Inhibitors; D006006:Glycogen Synthase; D005947:Glucose; D014532:Uridine Diphosphate Glucose