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Down-regulation of Sp1 activity through modulation of O-glycosylation by treatment with a low glucose mimetic, 2-deoxyglucose.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2003 Dec 19; Vol. 278 (51), pp. 51223-31. Date of Electronic Publication: 2003 Oct 07. - Publication Year :
- 2003
-
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 GlcNAc in 2-DG-treated cells, which is at least partially attributed to the inhibitory effect of 2-DG on N-acetyl-beta-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.
- Subjects :
- Acetylglucosamine pharmacology
Cell Line, Tumor
Cyclin-Dependent Kinase Inhibitor p21
Cyclins genetics
Glycosylation drug effects
Humans
Molecular Mimicry
Oncogene Proteins, Viral biosynthesis
Promoter Regions, Genetic drug effects
Transcription, Genetic drug effects
Antimetabolites pharmacology
DNA-Binding Proteins
Deoxyglucose pharmacology
Down-Regulation drug effects
Sp1 Transcription Factor metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 278
- Issue :
- 51
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 14532290
- Full Text :
- https://doi.org/10.1074/jbc.M307332200