Role of cyclic AMP response element-binding protein in cyclic AMP inhibition of NF-kappaB-mediated transcription.
The NF-kappaB family of transcription factors regulates the inducible expression of a variety of genes. Recently, we showed that elevation of intracellular cyclic AMP inhibits NF-kappaB-mediated transcription in human monocytes and endothelial cells without preventing nuclear translocation of NF-kappaB complexes. The present study examined the molecular mechanism of this inhibition. We hypothesized that activation of the protein kinase A signaling pathway may inhibit NF-kappaB-mediated transcription by phosphorylating proteins, such as cAMP response element-binding protein (CREB), which compete for limiting amounts of the coactivator CBP. Here, we show that the amino-terminal region (amino acids 1-450) of CBP specifically interacts with the carboxyl-terminal region (amino acids 286-551) of NF-kappaB p65 (RelA) both in vitro and in vivo. Functional studies using human endothelial cells demonstrated that overexpression of CBP rescued cAMP inhibition of NF-kappaB-mediated transcription and transcription mediated by a chimeric protein, GAL4-p65(286-551), which contained the GAL4 DNA binding domain fused to the carboxyl-terminal region of p65 (amino acids 286-551). In contrast, overexpression of CREB inhibited GAL4-p65(286-551)-mediated transcription. These results suggest that activation of the protein kinase A pathway inhibits NF-kappaB transcription by phosphorylating CREB, which competes with p65 for limiting amounts of CBP.
Parry
G C
GC
Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Mackman
N
N
D002135:Calcium-Binding Proteins; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000494:pharmacology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000502:physiology*; D004727:Endothelium / Q000166:cytology; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D009000:Monocytes / Q000166:cytology; D016328:NF-kappa B / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D050863:Synaptotagmin I; D050857:Synaptotagmins; D014158:Transcription, Genetic / Q000187:drug effects*
D002135:Calcium-Binding Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D009419:Nerve Tissue Proteins; D050863:Synaptotagmin I; D050857:Synaptotagmins; D000242:Cyclic AMP