Down-regulation of Sp1 Activity through Modulation of O-Glycosylation by Treatment with a Low Glucose Mimetic, 2-Deoxyglucose

Hyun Tae Kang, Jung Won Ju, Jin Won Cho, Eun Seong Hwang

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

2-Deoxyglucose (2-DG), a nonmetabolizable glucose analogue, blocks glycolysis at the phosphohexose isomerase step and has been frequently used as a glucose starvation mimetic in studies of a wide variety of physiological dysfuctions. However, the effect of 2-DG on protein glycosylation and related signal pathways has not been investigated in depth. In HeLa, an HPV18-positive cervical carcinoma line, 2-DG treatment down-regulates human papillomavirus early gene transcription. This down-regulation was also achieved by low glucose supply or hypoxia, suggesting that this is a response commonly modulated by cellular glucose or energy level. We investigated how 2-DG and low glucose affect transcriptional activity. Human papillomavirus gene transcription was only marginally affected by the inhibition of ATP synthesis or the supplementation of pyruvate to 2-DG-treated cells, suggesting that poor ATP generation is involved only to a limited extent. 2-DG treatment also inhibited activation of p21 WAF1 promoter, which is controlled by p53 and/or Sp1. In a reporter assay using p21 WAF1 promoter constructs, 2-DG exerted a strong inhibitory effect on Sp1 activity. DNA binding activity of Sp1 in 2-DG-treated HeLa cells was intact, whereas it was severely impaired in cells incubated in a low glucose medium or in hypoxic condition. Unexpectedly, Sp1 was heavily modified with Glc-NAc in 2-DG-treated cells, which is at least partially attributed to the inhibitory effect of 2-DG on N-acetyl-β -D-glucosaminidase activity. Our results suggest that 2-DG, like low glucose or hypoxic condition, down-regulates Sp1 activity, but through hyper-GlcNAcylation instead of hypo-GlcNAcylation.

Original languageEnglish
Pages (from-to)51223-51231
Number of pages9
JournalJournal of Biological Chemistry
Volume278
Issue number51
DOIs
Publication statusPublished - 2003 Dec 19

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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