title: A20 inhibits LUBAC-mediated NF-κB activation by binding linear polyubiquitin chains via its zinc finger 7.
abstract: Linear polyubiquitination of proteins has recently been implicated in NF-κB signalling and is mediated by the linear ubiquitin chain assembly complex (LUBAC), consisting of HOIL-1, HOIP and Sharpin. However, the mechanisms that regulate linear ubiquitination are still unknown. Here, we show that A20 is rapidly recruited to NEMO and LUBAC upon TNF stimulation and that A20 inhibits LUBAC-induced NF-κB activation via its C-terminal zinc-finger 7 (ZF7) domain. Expression of a polypeptide corresponding to only ZF7 was sufficient to inhibit TNF-induced NF-κB activation. Both A20 and ZF7 can form a complex with NEMO and LUBAC, and are able to prevent the TNF-induced binding of NEMO to LUBAC. Finally, we show that ZF7 preferentially binds linear polyubiquitin chains in vitro, indicating A20-ZF7 as a novel linear ubiquitin-binding domain (LUBID). We thus propose a model in which A20 inhibits TNF- and LUBAC-induced NF-κB signalling by binding to linear polyubiquitin chains via its seventh zinc finger, which prevents the TNF-induced interaction between LUBAC and NEMO.
authors.affiliation: Department for Molecular Biomedical Research, Unit of Molecular Signal Transduction in Inflammation, VIB, Ghent, Belgium.
authors.forename: Kelly
authors.initials: K
authors.lastname: Verhelst
authors.forename: Isabelle
authors.initials: I
authors.lastname: Carpentier
authors.forename: Marja
authors.initials: M
authors.lastname: Kreike
authors.forename: Laura
authors.initials: L
authors.lastname: Meloni
authors.forename: Lynn
authors.initials: L
authors.lastname: Verstrepen
authors.forename: Tobias
authors.initials: T
authors.lastname: Kensche
authors.forename: Ivan
authors.initials: I
authors.lastname: Dikic
authors.forename: Rudi
authors.initials: R
authors.lastname: Beyaert
mesh_terms: D004268:DNA-Binding Proteins / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D025821:Polyubiquitin / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D016335:Zinc Fingers / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; C491731:IKBKG protein, human; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D014409:Tumor Necrosis Factor-alpha; D025821:Polyubiquitin; D051550:I-kappa B Kinase; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3