title: Tyrosine nitration on p65: a novel mechanism to rapidly inactivate nuclear factor-kappaB.
abstract: NO is an important factor that induces post-translational modifications of proteins by cellular reduction and oxidation mechanism: cysteinyl-nitrosylation or Tyr nitration. Nuclear factor (NF)-kappaB activity can be rapidly suppressed by sodium nitroprusside, a NO donor. This effect was effectively reversed by peroxynitrite scavenger deferoxamine, suggesting a Tyr nitration-mediated mechanism. Western blot with nitrotyrosine-specific antibody demonstrated that the p65 subunit of NF-kappaB was predominantly nitrated on Tyr residues. Tyr nitration of p65 induced its dissociation from p50, its association with IkappaBalpha, and subsequent sequestration of p65 in the cytoplasm by IkappaBalpha-mediated export. Liquid chromatography-coupled nanoelectrospray mass spectrometry revealed specific nitration on Tyr-66 and Tyr-152 residues of p65. Mutation studies confirmed that both Tyr-66 and Tyr-152 residues were important for the direct effects of NO on p65, which resulted in more p65 export and inactivation of NF-kappaB activity. This study identified a novel and efficient pathway where NO rapidly inactivated NF-kappaB activity by inducing Tyr nitration on p65.
authors.affiliation: Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA.
authors.forename: Sung Wook
authors.initials: SW
authors.lastname: Park
authors.forename: M D Mostaqul
authors.initials: MD
authors.lastname: Huq
authors.forename: Xinli
authors.initials: X
authors.lastname: Hu
authors.forename: Li-Na
authors.initials: LN
authors.lastname: Wei
mesh_terms: D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D002853:Chromatography, Liquid; D003676:Deferoxamine / Q000494:pharmacology; D006801:Humans; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D030421:Peroxynitrous Acid / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D021241:Spectrometry, Mass, Electrospray Ionization; D051996:Transcription Factor RelA; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D016328:NF-kappa B; D020030:Nitric Oxide Donors; D051996:Transcription Factor RelA; D030421:Peroxynitrous Acid; D009599:Nitroprusside; D009569:Nitric Oxide; D014443:Tyrosine; D003676:Deferoxamine