ABSTRACT
Poly(ADP-ribose) polymerase-1 (PARP-1) and nuclear factor kappaB (NF-kappaB) have both been demonstrated to play a pathophysiological role in a number of inflammatory disorders. We recently presented evidence that PARP-1 can act as a promoter-specific coactivator of NF-kappaB in vivo independent of its enzymatic activity. PARP-1 directly interacts with p300 and both subunits of NF-kappaB (p65 and p50) and synergistically coactivates NF-kappaB-dependent transcription. Here we show that PARP-1 is acetylated in vivo at specific lysine residues by p300/CREB-binding protein upon stimulation. Furthermore, acetylation of PARP-1 at these residues is required for the interaction of PARP-1 with p50 and synergistic coactivation of NF-kappaB by p300 and the Mediator complex in response to inflammatory stimuli. PARP-1 physically interacts with the Mediator. Interestingly, PARP-1 interacts in vivo with histone deacetylases (HDACs) 1-3 but not with HDACs 4-6 and might be deacetylated in vivo by HDACs 1-3. Thus, acetylation of PARP-1 by p300/CREB-binding protein plays an important regulatory role in NF-kappaB-dependent gene activation by enhancing its functional interaction with p300 and the Mediator complex.
Subject(s)
CREB-Binding Protein/metabolism , Gene Expression Regulation/physiology , NF-kappa B/physiology , Poly(ADP-ribose) Polymerases/metabolism , Acetylation , Animals , Cell Cycle Proteins/analysis , Cell Cycle Proteins/physiology , Chemokine CXCL2 , Chemokines/genetics , Histone Acetyltransferases/analysis , Histone Acetyltransferases/physiology , Macrophages/metabolism , Mice , Mice, Knockout , NF-kappa B/pharmacology , Nitric Oxide Synthase Type II/genetics , Poly (ADP-Ribose) Polymerase-1 , Poly(ADP-ribose) Polymerases/deficiency , Poly(ADP-ribose) Polymerases/genetics , Promoter Regions, Genetic/genetics , Transcription Factors/analysis , Transcription Factors/physiology , Transcription, Genetic , Transcriptional Activation , Transfection , Tumor Necrosis Factor-alpha/pharmacology , p300-CBP Transcription FactorsABSTRACT
Nuclear factor kappaB (NF-kappaB) plays an important role in the transcriptional regulation of genes involved in inflammation and cell survival. Here, we show that coactivator-associated arginine methyltransferase CARM1/PRMT4 is a novel transcriptional coactivator of NF-kappaB and functions as a promoter-specific regulator of NF-kappaB recruitment to chromatin. Carm1 knockout cells showed impaired expression of a subset of NF-kappaB-dependent genes upon TNFalpha or LPS stimulation. CARM1 forms a complex with p300 and NF-kappaB in vivo and interacts directly with the NF-kappaB subunit p65 in vitro. CARM1 seems to act in a gene-specific manner mainly by enhancing NF-kappaB recruitment to cognate sites. Moreover, CARM1 synergistically coactivates NF-kappaB-mediated transactivation, in concert with the transcriptional coactivators p300/CREB-binding protein and the p160 family of steroid receptor coactivators. For at least a subset of CARM1-dependent NF-kappaB target genes, the enzymatic activities of both CARM1 and p300 are necessary for the observed synergy between CARM1 and p300. Our results suggest that the cooperative action between protein arginine methyltransferases and protein lysine acetyltransferases regulates NF-kappaB-dependent gene activation in vivo.
