cis-acting, element-specific transcriptional activity of differentially phosphorylated nuclear factor-kappa B.
Phosphorylation of nuclear factor-kappa B (NF-kappa B) subunits emerges as a mechanism by which transcriptional activity of nuclear NF-kappa B complexes is regulated in an inhibitor kappa B-independent fashion. As the main transactivator, the p65 subunit of NF-kappa B has an outstanding position in the hierarchy of NF-kappa B proteins. p65 is a multiply phosphorylated protein with phosphorylation sites in the C-terminal transactivation domain and the N-terminal Rel homology domain (RHD). In this study, we describe two previously non-reported phospho-acceptor sites within the p65 RHD. We show that differential phosphorylation of serine residues within the RHD modulates transcriptional activity in a cis-acting element and promoter-specific context, thus leading to a phosphorylation state-dependent gene expression profile. RelA(-/-) mouse embryonic fibroblasts reconstituted with wild-type p65 or p65 phosphorylation-deficient mutants showed a distinctive expression profile of synthetic kappa B-dependent reporters as well as endogenous genes. Hypophosphorylated p65 did not display cis-acting element-specific changes in DNA binding or dimerization behavior. This study shows for the first time that site-specific phosphorylation can target a transcription factor to a particular subset of genes.
Anrather
Josef
J
Division of Neurobiology, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York 10021, USA. joa@med.cornell.edu
Racchumi
Gianfranco
G
Iadecola
Costantino
C
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002460:Cell Line; D005786:Gene Expression Regulation; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D016415:Sequence Alignment; D012694:Serine; D051996:Transcription Factor RelA; D014158:Transcription, Genetic
D016328:NF-kappa B; D051996:Transcription Factor RelA; D012694:Serine