The E3 ubiquitin ligase MIB2 enhances inflammation by degrading the deubiquitinating enzyme CYLD
| Autor: | Tsutomu Kai, Atsushi Uematsu, Shigeki Higashiyama, Chikako Takahashi, Tatsuya Sawasaki, Shuhei Yoshida, Fuminori Tokunaga, Kouhei Shimizu, Kohki Kido, Yuta Yanagihara, Mamoru Honda, Hirotaka Takahashi, Masashi Maekawa, Yuuki Imai, Noritaka Saeki |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Male Proteasome Endopeptidase Complex Ubiquitin-Protein Ligases Notch signaling pathway Biochemistry Deubiquitinating Enzyme CYLD Proinflammatory cytokine Deubiquitinating enzyme 03 medical and health sciences Mice Ubiquitin Animals Humans Polyubiquitin Molecular Biology Inflammation Mice Knockout 030102 biochemistry & molecular biology biology Deubiquitinating Enzymes Chemistry Tumor Necrosis Factor-alpha NF-kappa B Transcription Factor RelA Ubiquitination Cell Biology Ubiquitin ligase Cell biology RING finger domain Mice Inbred C57BL Cysteine Endopeptidases 030104 developmental biology HEK293 Cells Protein Synthesis and Degradation biology.protein Female Signal transduction HeLa Cells Signal Transduction |
| Zdroj: | J Biol Chem |
| Popis: | The tumor suppressor CYLD is a deubiquitinating enzyme that suppresses polyubiquitin-dependent signaling pathways, including the proinflammatory and cell growth–promoting NF-κB pathway. Missense mutations in the CYLD gene are present in individuals with syndromes such as multiple familial trichoepithelioma (MFT), but the pathogenic roles of these mutations remain unclear. Recent studies have shown that CYLD interacts with a RING finger domain protein, mind bomb homologue 2 (MIB2), in the regulation of NOTCH signaling. However, whether MIB2 is an E3 ubiquitin ligase that acts on CYLD is unknown. Here, using the cell-free–based AlphaScreen and pulldown assays to detect protein-protein interactions, along with immunofluorescence assays and murine Mib2 knockout cells and animals, we demonstrate that MIB2 promotes proteasomal degradation of CYLD and enhances NF-κB signaling. Of note, arthritic inflammation was suppressed in Mib2-deficient mice. We further observed that the ankyrin repeat in MIB2 interacts with the third CAP domain in CYLD and that MIB2 catalyzes Lys-48–linked polyubiquitination of CYLD at Lys-338 and Lys-530. MIB2-dependent CYLD degradation activated NF-κB signaling via tumor necrosis factor alpha (TNFα) stimulation and the linear ubiquitination assembly complex (LUBAC). Mib2-knockout mice had reduced serum interleukin-6 (IL-6) and exhibited suppressed inflammatory responses in the K/BxN serum-transfer arthritis model. Interestingly, MIB2 significantly enhanced the degradation of a CYLD(P904L) variant identified in an individual with MFT, although the molecular pathogenesis of the disease was not clarified here. Together, these results suggest that MIB2 enhances NF-κB signaling in inflammation by promoting the ubiquitin-dependent degradation of CYLD. |
| Databáze: | OpenAIRE |
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