TRIM68 negatively regulates IFN-β production by degrading TRK fused gene, a novel driver of IFN-β downstream of anti-viral detection systems

PLoS One. 2014 Jul 7;9(7):e101503. doi: 10.1371/journal.pone.0101503. eCollection 2014.

Abstract

In recent years members of the tripartite motif-containing (TRIM) family of E3 ubiquitin ligases have been shown to both positively and negatively regulate viral defence and as such are emerging as compelling targets for modulating the anti-viral immune response. In this study we identify TRIM68, a close homologue of TRIM21, as a novel regulator of Toll-like receptor (TLR)- and RIG-I-like receptor (RLR)-driven type I IFN production. Proteomic analysis of TRIM68-containing complexes identified TRK-fused gene (TFG) as a potential TRIM68 target. Overexpression of TRIM68 and TFG confirmed their ability to associate, with TLR3 stimulation appearing to enhance the interaction. TFG is a known activator of NF-κB via its ability to interact with inhibitor of NF-κB kinase subunit gamma (IKK-γ) and TRAF family member-associated NF-κB activator (TANK). Our data identifies a novel role for TFG as a positive regulator of type I IFN production and suggests that TRIM68 targets TFG for lysosomal degradation, thus turning off TFG-mediated IFN-β production. Knockdown of TRIM68 in primary human monocytes resulted in enhanced levels of type I IFN and TFG following poly(I:C) treatment. Thus TRIM68 targets TFG, a novel regulator of IFN production, and in doing so turns off and limits type I IFN production in response to anti-viral detection systems.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autoantigens / chemistry
  • Autoantigens / metabolism*
  • DEAD Box Protein 58
  • DEAD-box RNA Helicases / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Immunity, Innate*
  • Interferon-beta / biosynthesis*
  • Interferon-beta / genetics
  • Promoter Regions, Genetic / genetics
  • Protein Structure, Tertiary
  • Proteins / metabolism*
  • Proteolysis
  • Receptors, Immunologic
  • Tripartite Motif Proteins
  • Ubiquitin-Protein Ligases / chemistry
  • Ubiquitin-Protein Ligases / deficiency
  • Ubiquitin-Protein Ligases / metabolism*
  • Ubiquitination
  • Viruses / immunology*

Substances

  • Autoantigens
  • Proteins
  • Receptors, Immunologic
  • TFG protein, human
  • Tripartite Motif Proteins
  • Interferon-beta
  • TRIM68 protein, human
  • Ubiquitin-Protein Ligases
  • RIGI protein, human
  • DEAD Box Protein 58
  • DEAD-box RNA Helicases