Transcriptional glucose signaling through the glucose response element is mediated by the pentose phosphate pathway

Bruno Doiron, Marie Hélène Cuif, Ruihuan Chen, Axel Kahn

Research output: Contribution to journalArticlepeer-review

115 Scopus citations

Abstract

Glucose catabolism induces the expression of the L-type pyruvate kinase (L-PK) gene through the glucose response element (GIRE). The metabolic pathway used by glucose after its phosphorylation to glucose 6-phosphate by glucokinase to induce L-PK gene expression in hepatocytes remains unknown. The sugar alcohol xylitol is metabolized to xylulose 5-phosphate, an intermediate of the nonoxidative branch of the pentose phosphate pathway. In this study, we demonstrated that xylitol at low concentration (0.5 mM) induced the expression of the L-PK/CAT construct in glucose-responsive mhAT3F hepatoma cells at the same level as 20 mM glucose, while it did not affect intracellular concentration of glucose 6-phosphate significantly. The effect of xylitol on the induction of the L-PK gene expression was noncumulative with that of glucose since 20 mM glucose plus 5 mM xylitol induced the expression of the L-PK/CAT construct similarly to 20 mM glucose alone. In hepatocytes in primary culture, 5 mM xylitol induced accumulation of the L- PK mRNA even in the absence of insulin. Furthermore, the response to xylitol as well as glucose required the presence of a functional GIRE. It can be assumed from these results that glucose induces the expression of the L-PK gene through the nonoxidative branch of the pentose phosphate pathway. The effect of xylitol at low concentration suggests that the glucose signal to the transcriptional machinery is mediated by xylulose 5-phosphate.

Original languageEnglish (US)
Pages (from-to)5321-5324
Number of pages4
JournalJournal of Biological Chemistry
Volume271
Issue number10
DOIs
StatePublished - Mar 8 1996
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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