Molecular mechanism of influenza A NS1-mediated TRIM25 recognition and inhibition

Nat Commun. 2018 May 8;9(1):1820. doi: 10.1038/s41467-018-04214-8.

Abstract

RIG-I is a viral RNA sensor that induces the production of type I interferon (IFN) in response to infection with a variety of viruses. Modification of RIG-I with K63-linked poly-ubiquitin chains, synthesised by TRIM25, is crucial for activation of the RIG-I/MAVS signalling pathway. TRIM25 activity is targeted by influenza A virus non-structural protein 1 (NS1) to suppress IFN production and prevent an efficient host immune response. Here we present structures of the human TRIM25 coiled-coil-PRYSPRY module and of complexes between the TRIM25 coiled-coil domain and NS1. These structures show that binding of NS1 interferes with the correct positioning of the PRYSPRY domain of TRIM25 required for substrate ubiquitination and provide a mechanistic explanation for how NS1 suppresses RIG-I ubiquitination and hence downstream signalling. In contrast, the formation of unanchored K63-linked poly-ubiquitin chains is unchanged by NS1 binding, indicating that RING dimerisation of TRIM25 is not affected by NS1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cells, Cultured
  • DEAD Box Protein 58 / immunology
  • HEK293 Cells
  • Humans
  • Interferons / biosynthesis
  • Protein Binding
  • Protein Domains
  • Protein Multimerization
  • RNA, Viral / immunology
  • Receptors, Immunologic
  • Signal Transduction
  • Transcription Factors / antagonists & inhibitors*
  • Transcription Factors / chemistry
  • Transcription Factors / immunology*
  • Tripartite Motif Proteins / antagonists & inhibitors*
  • Tripartite Motif Proteins / chemistry
  • Tripartite Motif Proteins / immunology*
  • Ubiquitin-Protein Ligases / antagonists & inhibitors*
  • Ubiquitin-Protein Ligases / chemistry
  • Ubiquitin-Protein Ligases / immunology*
  • Ubiquitination
  • Viral Nonstructural Proteins / chemistry*
  • Viral Nonstructural Proteins / immunology*

Substances

  • INS1 protein, influenza virus
  • RNA, Viral
  • Receptors, Immunologic
  • Transcription Factors
  • Tripartite Motif Proteins
  • Viral Nonstructural Proteins
  • Interferons
  • TRIM25 protein, human
  • Ubiquitin-Protein Ligases
  • RIGI protein, human
  • DEAD Box Protein 58