title: Role of cysteine residues of p65/NF-kappaB on the inhibition by the sesquiterpene lactone parthenolide and N-ethyl maleimide, and on its transactivating potential.
abstract: Sesquiterpene lactones (SLs) are potent anti-inflammatory substances. It was previously shown that the anti-inflammatory effect could be partly explained by the inhibition of the transcription factor NF-kappaB. Whether they inhibit the DNA binding of NF-kappaB, the activation of the IkappaB-kinase, or both is still a matter of debate. The data supporting these hypotheses were obtained using different cell systems. In this contribution we analyzed the mechanism of the sesquiterpene lactone-mediated inhibition using different cell systems, and showed that in all the cell lines analyzed, SLs inhibited both NF-kappaB binding and the IkappaB-kinase, but that the former played a more preponderant role in the inhibition. These results again confirm the importance of cysteine 38 in the inhibition and regulation of NF-kappaB's function. Moreover, we compared the selectivity of the SL parthenolide with that of N-ethyl maleimide (NEM). We showed that NEM directly alkylated p65 as well as p50 of NF-kappaB, whereas SLs possess a selectivity towards p65. Finally, we studied the transactivating properties of various p65 mutants, to analyze the effect of exchanged cysteine residues in the DNA binding domain of NF-kappaB/p65 on its function and demonstrated that the transactivating potential of the mutants did not correlate with their DNA binding strenght.
authors.affiliation: Department of Pharmaceutical Biology, Institute of Pharmaceutical Science, Albert-Ludwigs-University Freiburg, Stefan-Meier-Str. 19, 79104 Freiburg, Germany.
authors.forename: A J
authors.initials: AJ
authors.lastname: García-Piñeres
authors.forename: M T
authors.initials: MT
authors.lastname: Lindenmeyer
authors.forename: I
authors.initials: I
authors.lastname: Merfort
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002135:Calcium-Binding Proteins; D003545:Cysteine; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D005033:Ethylmaleimide / Q000494:pharmacology*; D006367:HeLa Cells; D006801:Humans; D051550:I-kappa B Kinase; D019169:Jurkat Cells; D008264:Macrophages; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009154:Mutation; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D012717:Sesquiterpenes / Q000494:pharmacology*; D050863:Synaptotagmin I; D050857:Synaptotagmins; D051996:Transcription Factor RelA; D015533:Transcriptional Activation / Q000187:drug effects*; D014162:Transfection
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D009419:Nerve Tissue Proteins; D012717:Sesquiterpenes; D050863:Synaptotagmin I; D051996:Transcription Factor RelA; D050857:Synaptotagmins; C002669:parthenolide; D017346:Protein Serine-Threonine Kinases; C496559:CHUK protein, human; C496564:Chuk protein, mouse; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human; C496562:Ikbkb protein, mouse; C496566:Ikbke protein, mouse; D003545:Cysteine; D005033:Ethylmaleimide