The ubiquitin-like domain of TANK-binding kinase 1 mediates its binding and antagonism by snakehead vesiculovirus (SHVV) phosphoprotein to facilitate virus replication.

Abstract

The snakehead vesiculovirus (SHVV) is an emerging and highly pathogenic rhabdovirus that infects a variety of economically important fish species, posing a serious threat to the sustainable development of aquaculture. The phosphoprotein (P) of rhabdoviruses is known to facilitate viral replication and host immune evasion, although the precise mechanisms remain unclear. In this study, the spleen transcriptomic analysis of SHVV-infected fish revealed significantly enriched signaling pathways, and pull-down assays coupled with mass spectrometry identified TANK-binding kinase 1 (TBK1) ranked the first among the interacting protein with SHVV-P. The direct interaction was further confirmed through AlphaFold3-based structural prediction, molecular docking, co-immunoprecipitation (Co-IP), circular dichroism spectroscopy, and fluorescence co-localization assays. The structural properties of TBK1 in snakehead were subsequently characterized, and its response to SHVV infection was examined. Furthermore, overexpression of TBK1 enhanced interferon production and suppressed viral replication both in vitro and in vivo. Conversely, overexpression of the SHVV-P antagonized the TBK1-mediated antiviral response. Finally, structural modeling, Co-IP, and co-localization assays demonstrated that the ubiquitin-like domain (ULD) of TBK1 was responsible for its binding with the SHVV-P. These findings provide novel insights into the pathogenesis of SHVV and lay a foundation for the development of targeted control strategies against this virus.