A small molecule ubiquitination inhibitor blocks NF-kappa B-dependent cytokine expression in cells and rats
| Autor: | Pamela Volkel, Yi-Zheng Xu, Martin Huber, Teresa Biegel, Chakkodabylu S. Ramesha, Simon W. Lee, Marie Dinh, Liliana E. Scarafia, Jim W. Barnett, Qing-Fen Gan, Amy Y. Mak, Stacie A. Dalrymple, On-Yee So, James Patrick Dunn, Mary Mulkins, David C. Swinney, Ina Lee |
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| Rok vydání: | 2002 |
| Předmět: |
Male
Lysine Alpha (ethology) Tetrazoles Biochemistry Jurkat cells Substrate Specificity chemistry.chemical_compound Ubiquitin NF-KappaB Inhibitor alpha Animals Humans Enzyme Inhibitors Rats Wistar Molecular Biology biology NF-kappa B NF-κB Cell Biology NFKB1 Molecular biology Ubiquitin ligase Rats DNA-Binding Proteins chemistry Sulfoxides biology.protein Cytokines Tumor necrosis factor alpha I-kappa B Proteins |
| Zdroj: | The Journal of biological chemistry. 277(26) |
| ISSN: | 0021-9258 |
| Popis: | A small molecule inhibitor of NF-kappaB-dependent cytokine expression was discovered that blocked tumor necrosis factor (TNF) alpha-induced IkappaB(alpha) degradation in MM6 cells but not the degradation of beta-catenin in Jurkat cells. Ro106-9920 blocked lipopolysaccharide (LPS)-dependent expression of TNFalpha, interleukin-1beta, and interleukin-6 in fresh human peripheral blood mononuclear cells with IC(50) values below 1 microm. Ro106-9920 also blocked TNFalpha production in a dose-dependent manner following oral administration in two acute models of inflammation (air pouch and LPS challenge). Ro106-9920 was observed to inhibit an ubiquitination activity that does not require betaTRCP but associates with IkappaB(alpha) and will ubiquitinate IkappaB(alpha) S32E,S36E (IkappaB(alpha)(ee)) specifically at lysine 21 or 22. Ro106-9920 was identified in a cell-free system as a time-dependent inhibitor of IkappaB(alpha)(ee) ubiquitination with an IC(50) value of 2.3 +/- 0.09 microm. The ubiquitin E3 ligase activity is inhibited by cysteine-alkylating reagents, supported by E2UBCH7, and requires cIAP2 or a cIAP2-associated protein for activity. These activities are inconsistent with what has been reported for SCF(betaTRCP), the putative E3 for IkappaB(alpha) ubiquitination. Ro106-9920 was observed to be selective for IkappaB(alpha)(ee) ubiquitination over the ubiquitin-activating enzyme (E1), E2UBCH7, nonspecific ubiquitination of cellular proteins, and 97 other molecular targets. We propose that Ro106-9920 selectively inhibits an uncharacterized but essential ubiquitination activity associated with LPS- and TNFalpha-induced IkappaB(alpha) degradation and NF-kappaB activation. |
| Databáze: | OpenAIRE |
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