Modification of RelA by O-linked N-acetylglucosamine links glucose metabolism to NF-κB acetylation and transcription

The molecular mechanisms linking glucose metabolism with active transcription remain undercharacterized in mammalian cells. Using nuclear factor-kappa B (NF-kappa B) as a glucose-responsive transcription factor, we show that cells use the hexosamine biosynthesis pathway and O-linked beta-N-acetylglucosamine (O-GlcNAc) transferase (OGT) to potentiate gene expression in response to tumor necrosis factor (TNF) or etoposide. Chromatin immunoprecipitation assays demonstrate that, upon induction, OGT localizes to NF-kappa B-regulated promoters to enhance RelA acetylation. Knockdown of OGT abolishes p300-mediated acetylation of RelA on K310, a posttranslational mark required for full NF-kappa B transcription. Mapping studies reveal T305 as an important residue required for attachment of the O-GlcNAc moiety on RelA. Furthermore, p300 fails to acetylate a full-length RelA(T305A) mutant, linking O-GlcNAc and acetylation events on NF-kappa B. Reconstitution of RelA null cells with the RelA(T305A) mutant illustrates the importance of this residue for NF-kappa B-dependent gene expression and cell survival. Our work provides evidence for a unique regulation where attachment of the O-GlcNAc moiety to RelA potentiates p300 acetylation and NF-kappa B transcription.