Molecular mechanism of influenza A NS1-mediated TRIM25 recognition and inhibition.
Koliopoulos, M.G., Lethier, M., van der Veen, A.G., Haubrich, K., Hennig, J., Kowalinski, E., Stevens, R.V., Martin, S.R., Reis E Sousa, C., Cusack, S., Rittinger, K.(2018) Nat Commun 9: 1820-1820
- PubMed: 29739942 
- DOI: https://doi.org/10.1038/s41467-018-04214-8
- Primary Citation of Related Structures:  
5NT1, 5NT2, 6FLM, 6FLN - PubMed 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.
Organizational Affiliation: 
Molecular Structure of Cell Signalling Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.