title: IRF7 activation by Epstein-Barr virus latent membrane protein 1 requires localization at activation sites and TRAF6, but not TRAF2 or TRAF3.
abstract: Epstein-Barr virus (EBV) latent infection membrane protein 1 (LMP1), a constitutively aggregated and activated pseudoreceptor, activates IFN regulatory factor 7 (IRF7) through RIP1. We now report that the LMP1 cytoplasmic carboxyl terminal amino acids 379-386 bound IRF7 and activated IRF7. IRF7 activation required TRAF6 and RIP1, but not TRAF2 or TRAF3. LMP1 Y(384)YD(386), which are required for TRADD and RIP1 binding and for NF-kappaB activation, were not required for IRF7 binding, but were required for IRF7 activation, implicating signaling through TRADD and RIP1 in IRF7 activation. Association with active LMP1 signaling complexes was also critical for IRF7 activation because (i) a dominant-negative IRF7 bound to LMP1, blocked IRF7 association and activation, but did not inhibit LMP1 induced NF-kappaB or TBK1 or Sendai virus-mediated IFN stimulated response element activation; and (ii) two different LMP1 transmembrane domain mutants, which fail to aggregate, each bound IRF7 and prevented LMP1 from binding and activating IRF7 in the same cell, but did not prevent NF-kappaB activation. Thus, efficient IRF7 activation required association with LMP1 CTAR2 in proximity to LMP1 CTAR2 mediated kinase activation sites.
authors.affiliation: Department of Microbiology, Channing Laboratory/Brigham & Women's Hospital, Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Yoon-Jae
authors.initials: YJ
authors.lastname: Song
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Izumi
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Shinners
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Gewurz
authors.forename: Elliott
authors.initials: E
authors.lastname: Kieff
mesh_terms: D006801:Humans; D047468:Immunoprecipitation; D050839:Interferon Regulatory Factor-7 / Q000502:physiology*; D007372:Interferons / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D028861:Nuclear Pore Complex Proteins / Q000378:metabolism; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000378:metabolism; D015398:Signal Transduction; D053199:TNF Receptor-Associated Death Domain Protein / Q000378:metabolism; D047992:TNF Receptor-Associated Factor 2 / Q000502:physiology*; D048008:TNF Receptor-Associated Factor 3 / Q000502:physiology*; D048029:TNF Receptor-Associated Factor 6 / Q000502:physiology*; D020798:Two-Hybrid System Techniques; D014763:Viral Matrix Proteins / Q000502:physiology*
chemical_list: C119724:AGFG1 protein, human; C037662:EBV-associated membrane antigen, Epstein-Barr virus; C494234:IRF7 protein, human; D050839:Interferon Regulatory Factor-7; D016328:NF-kappa B; D028861:Nuclear Pore Complex Proteins; D016601:RNA-Binding Proteins; D053199:TNF Receptor-Associated Death Domain Protein; D047992:TNF Receptor-Associated Factor 2; D048008:TNF Receptor-Associated Factor 3; D048029:TNF Receptor-Associated Factor 6; D014763:Viral Matrix Proteins; D007372:Interferons