CYLD Limits Lys63- and Met1-Linked Ubiquitin at Receptor Complexes to Regulate Innate Immune Signaling

• Published in: Cell reports (Cambridge) 2016-03, Vol.14 (12), p.2846-2858
• Main Authors: Hrdinka, Matous, Fiil, Berthe Katrine, Zucca, Mattia, Leske, Derek, Bagola, Katrin, Yabal, Monica, Elliott, Paul R., Damgaard, Rune Busk, Komander, David, Jost, Philipp J., Gyrd-Hansen, Mads
• Format: Article
• Language: English
• Subjects: Catalytic Domain; Cell Line, Tumor; Cytokines - metabolism; Deubiquitinating Enzymes - antagonists & inhibitors; Deubiquitinating Enzymes - genetics; Deubiquitinating Enzymes - metabolism; Endopeptidases - chemistry; Endopeptidases - genetics; Endopeptidases - metabolism; HEK293 Cells; Humans; Immunity, Innate; Lysine - chemistry; Lysine - metabolism; Methionine - chemistry; Methionine - metabolism; Mutagenesis, Site-Directed; NF-kappa B - metabolism; Receptor-Interacting Protein Serine-Threonine Kinase 2 - metabolism; RNA Interference; RNA, Small Interfering - metabolism; Signal Transduction; Ubiquitin - chemistry; Ubiquitin - genetics; Ubiquitin - metabolism; Ubiquitin-Protein Ligases - antagonists & inhibitors; Ubiquitin-Protein Ligases - chemistry; Ubiquitin-Protein Ligases - metabolism; Ubiquitination
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2016.02.062

Innate immune signaling relies on the deposition of non-degradative polyubiquitin at receptor-signaling complexes, but how these ubiquitin modifications are regulated by deubiquitinases remains incompletely understood. Met1-linked ubiquitin (Met1-Ub) is assembled by the linear ubiquitin assembly complex (LUBAC), and this is counteracted by the Met1-Ub-specific deubiquitinase OTULIN, which binds to the catalytic LUBAC subunit HOIP. In this study, we report that HOIP also interacts with the deubiquitinase CYLD but that CYLD does not regulate ubiquitination of LUBAC components. Instead, CYLD limits extension of Lys63-Ub and Met1-Ub conjugated to RIPK2 to restrict signaling and cytokine production. Accordingly, Met1-Ub and Lys63-Ub were individually required for productive NOD2 signaling. Our study thus suggests that LUBAC, through its associated deubiquitinases, coordinates the deposition of not only Met1-Ub but also Lys63-Ub to ensure an appropriate response to innate immune receptor activation. [Display omitted] •CYLD associates with LUBAC via HOIP and limits signaling by NOD2•RIPK2 ubiquitination is regulated by CYLD and OTULIN•CYLD trims Lys63 and Met1 linkages conjugated to RIPK2•Productive NOD2 signaling requires Lys63 and Met1 linkages Hrdinka et al. show that productive signaling by the bacterial sensor NOD2 requires formation of Lys63- and Met1-linked ubiquitin. Both ubiquitin linkages are targeted by the deubiquitinase CYLD, which together with OTULIN regulates RIPK2 ubiquitination to restrict NOD2 signaling and cytokine production.