Oxidation of Ikappa Balpha at methionine 45 is one cause of taurine chloramine-induced inhibition of NF-kappa B activation

J Biol Chem. 2002 Jul 5;277(27):24049-56. doi: 10.1074/jbc.M110832200. Epub 2002 Apr 30.

Abstract

A band shift of IkappaBalpha was observed in Western blots with Jurkat cells treated with 1 mm taurine chloramine (TauCl) for 1 h. TauCl treatment inhibited tumor necrosis factor alpha (TNFalpha)-initiated nuclear factor kappaB (NF-kappaB) activation. TauCl did not inhibit either the upstream of IkappaB kinase (IKK) activation or IKK itself but did inhibit NF-kappaB activation induced by IKK overexpression. Deletion experiments showed that a TauCl modification site causing the band shift of IkappaBalpha is Met45. High performance liquid chromatography and mass spectrometry analyses of a small peptide containing Met45 revealed that TauCl oxidizes Met45. A mutant of IkappaBalpha whose Met45 was converted to alanine did not generate a band shift upon TauCl treatment and degraded in response to TNFalpha stimulation. However, a reporter assay revealed that NF-kappaB-dependent luciferase expression was not fully recovered in cells transfected with this mutant. These results indicate that Met45 oxidation of IkappaBalpha is a molecular mechanism underlying the TauCl-induced inhibition of NF-kappaB activation. A similar band shift was observed when HL-60 cells expressing myeloperoxidase were treated with 100 microm hydrogen peroxide for 5 min. When rat neutrophils were incubated with bacteria, intracellular taurine decreased interleukin-8 production. Therefore, taurine may help suppress excessive inflammatory reaction in neutrophils.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Cell Line
  • Chromatography, High Pressure Liquid
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Genes, Reporter
  • Humans
  • I-kappa B Proteins*
  • Interleukin-8 / metabolism
  • Jurkat Cells
  • Kinetics
  • Luciferases / genetics
  • Luciferases / metabolism
  • Mass Spectrometry
  • Methionine
  • Mutagenesis, Site-Directed
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / metabolism*
  • Oligonucleotide Probes
  • Oxidation-Reduction
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Taurine / analogs & derivatives
  • Taurine / pharmacology*

Substances

  • DNA-Binding Proteins
  • Enzyme Inhibitors
  • I-kappa B Proteins
  • Interleukin-8
  • NF-kappa B
  • NFKBIA protein, human
  • Nfkbia protein, rat
  • Oligonucleotide Probes
  • Recombinant Proteins
  • NF-KappaB Inhibitor alpha
  • Taurine
  • N-chlorotaurine
  • Methionine
  • Luciferases