OTUB1 is a key regulator of RIG-I dependent immune signalling and is targeted for proteasomal degradation by influenza A NS1

Jahan, A. S.; Biquand, E.; Munoz-Moreno, R.; Le Quang, A.; Mok, C. K.-P.; Wong, H. H.; Teo, Q. W.; Doak, S.; Chin, A.; Poon, L. L. M.; te Velthuis, A.; Garcia-Sastre, A.; Demeret, C.; Sanyal, S.

doi:10.1101/634014

bioRxiv · 10.1101/634014

OTUB1 is a key regulator of RIG-I dependent immune signalling and is targeted for proteasomal degradation by influenza A NS1

Jahan, A. S.·Biquand, E.·Munoz-Moreno, R.·Le Quang, A.·Mok, C. K.-P.·Wong, H. H.·Teo, Q. W.·Doak, S.·Chin, A.·Poon, L. L. M.·te Velthuis, A.·Garcia-Sastre, A.·Demeret, C.·Sanyal, S.

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Abstract

Deubiquitylases (DUBs) regulate critical signaling pathways at the intersection of host innate immunity and viral pathogenesis. Although RIG-I activation is heavily dependent on ubiquitylation, DUBs that regulate this pathway have not been identified. Using a ubiquitin C-terminal electrophile, we profiled DUBs that function during influenza A virus (IAV) infection, and isolated OTUB1 as a key regulator of RIG-I dependent antiviral responses. OTUB1 was interferon-inducible, and interacted with RIG-I, viral PB2 and NS1. Upon infection, OTUB1 relocalised from the nucleus to mitochondrial membranes, and activated the RIG-I signaling complex via hydrolysis of K48 polyubiquitin chains and by forming a repressive complex with UBCH5c. Using a reconstituted system composed of in vitro translated [35S]IRF3, purified RIG-I, mitochondrial membranes and cytosol expressing OTUB1 variants, we recapitulated the mechanism of OTUB1-dependent RIG-I activation. A wide range of IAV NS1 proteins triggered proteasomal degradation of OTUB1, thereby antagonizing the RIG-I signaling cascade and antiviral responses.\n\nHighlightsO_LIOTUB1 is induced during influenza A virus infections in an IFN-I dependent manner\nC_LIO_LIOTUB1 regulates the RIG-I complex by hydrolysing K48-linked polyubiquitin chains and by sequestering UBCH5c to prevent K48 polyubiquitylation\nC_LIO_LIOptimal K63 versus K48 polyubiquitin chain concentrations determine RIG-I activation\nC_LIO_LIInfluenza NS1 targets OTUB1 for proteasomal degradation\nC_LI

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Jahan, A. S., Biquand, E., Munoz-Moreno, R., Le Quang, A., Mok, C. K.-P., Wong, H. H., Teo, Q. W., Doak, S., Chin, A., Poon, L. L. M., te Velthuis, A., Garcia-Sastre, A., Demeret, C., Sanyal, S.. 2019-05-15. OTUB1 is a key regulator of RIG-I dependent immune signalling and is targeted for proteasomal degradation by influenza A NS1. https://doi.org/10.1101/634014

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