Download MendeleyThe E3 ligase Riplet promotes RIG-I signaling independent of RIG-I oligomerization.
Wang, W., Gotte, B., Guo, R., Pyle, A.M.(2023) Nat Commun 14: 7308-7308
- PubMed: 37951994
- DOI: https://doi.org/10.1038/s41467-023-42982-0
- Primary Citation of Related Structures:
8G7T, 8G7U, 8G7V - PubMed Abstract:
RIG-I is an essential innate immune receptor that responds to infection by RNA viruses. The RIG-I signaling cascade is mediated by a series of post-translational modifications, the most important of which is ubiquitination of the RIG-I Caspase Recruitment Domains (CARDs) by E3 ligase Riplet. This is required for interaction between RIG-I and its downstream adapter protein MAVS, but the mechanism of action remains unclear. Here we show that Riplet is required for RIG-I signaling in the presence of both short and long dsRNAs, establishing that Riplet activation does not depend upon RIG-I filament formation on long dsRNAs. Likewise, quantitative Riplet-RIG-I affinity measurements establish that Riplet interacts with RIG-I regardless of whether the receptor is bound to RNA. To understand this, we solved high-resolution cryo-EM structures of RIG-I/RNA/Riplet complexes, revealing molecular interfaces that control Riplet-mediated activation and enabling the formulation of a unified model for the role of Riplet in signaling.
Organizational Affiliation:
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, 06511, USA.
