title: A functional C-terminal TRAF3-binding site in MAVS participates in positive and negative regulation of the IFN antiviral response.
abstract: Recognition of viral RNA structures by the cytosolic sensor retinoic acid-inducible gene-I (RIG-I) results in the activation of signaling cascades that culminate with the generation of the type I interferon (IFN) antiviral response. Onset of antiviral and inflammatory responses to viral pathogens necessitates the regulated spatiotemporal recruitment of signaling adapters, kinases and transcriptional proteins to the mitochondrial antiviral signaling protein (MAVS). We previously demonstrated that the serine/threonine kinase IKKε is recruited to the C-terminal region of MAVS following Sendai or vesicular stomatitis virus (VSV) infection, mediated by Lys63-linked polyubiquitination of MAVS at Lys500, resulting in inhibition of downstream IFN signaling (Paz et al, Mol Cell Biol, 2009). In this study, we demonstrate that C-terminus of MAVS harbors a novel TRAF3-binding site in the aa450-468 region of MAVS. A consensus TRAF-interacting motif (TIM), 455-PEENEY-460, within this site is required for TRAF3 binding and activation of IFN antiviral response genes, whereas mutation of the TIM eliminates TRAF3 binding and the downstream IFN response. Reconstitution of MAVS(-/-) mouse embryo fibroblasts with a construct expressing a TIM-mutated version of MAVS failed to restore the antiviral response or block VSV replication, whereas wild-type MAVS reconstituted antiviral inhibition of VSV replication. Furthermore, recruitment of IKKε to an adjacent C-terminal site (aa 468-540) in MAVS via Lys500 ubiquitination decreased TRAF3 binding and protein stability, thus contributing to IKKε-mediated shutdown of the IFN response. This study demonstrates that MAVS harbors a functional C-terminal TRAF3-binding site that participates in positive and negative regulation of the IFN antiviral response.
authors.affiliation: Terry Fox Molecular Oncology Group, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec H3T1E2, Canada.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Paz
authors.forename: Myriam
authors.initials: M
authors.lastname: Vilasco
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Werden
authors.forename: Meztli
authors.initials: M
authors.lastname: Arguello
authors.forename: Deshanthe
authors.initials: D
authors.lastname: Joseph-Pillai
authors.forename: Tiejun
authors.initials: T
authors.lastname: Zhao
authors.forename: Thi Lien-Anh
authors.initials: TL
authors.lastname: Nguyen
authors.forename: Qiang
authors.initials: Q
authors.lastname: Sun
authors.forename: Eliane F
authors.initials: EF
authors.lastname: Meurs
authors.forename: Rongtuan
authors.initials: R
authors.lastname: Lin
authors.forename: John
authors.initials: J
authors.lastname: Hiscott
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D025461:Feedback, Physiological; D055786:Gene Knockout Techniques; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D007113:Immunity, Innate; D007370:Interferon Type I / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D010253:Respirovirus Infections / Q000276:immunology; D029082:Sendai virus / Q000276:immunology; D048008:TNF Receptor-Associated Factor 3 / Q000276:immunology / Q000378:metabolism*; D054243:Vesicular Stomatitis / Q000276:immunology; D018116:Vesiculovirus / Q000276:immunology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D007370:Interferon Type I; C505371:MAVS protein, human; D010446:Peptide Fragments; D048008:TNF Receptor-Associated Factor 3; C090656:TRAF3 protein, human; D051550:I-kappa B Kinase