Angiomotin Counteracts the Negative Regulatory Effect of Host WWOX on Viral PPxY-Mediated Egress

Filoviridae family members Ebola virus (EBOV) and Marburg virus (MARV) and Arenaviridae family member Lassa virus (LASV) are emerging pathogens that can cause hemorrhagic fever and high rates of death in humans. A better understanding of the interplay between these viruses and the host will provide information about the biology of these pathogens and may lead to the identification of new targets for therapeutic development. Notably, expression of the filovirus VP40 and LASV-Z matrix proteins alone drives assembly and egress of virus-like particles (VLPs). The conserved PPxY late (L)-domain motifs in the filovirus VP40 and LASV-Z proteins play a key role in the budding process by mediating interactions with select host WW-domain-containing proteins, which then regulate virus egress and spread. To identify the full complement of host WW-domain interactors, we utilized wild-type and mutant PPxY peptides from EBOV and MARV VP40 and LASV-Z proteins to screen an array of glutathione S-transferase-WW-domain fusion proteins. We identified WW-domain-containing oxidoreductase (WWOX) as a novel PPxY-dependent interactor, and we went on to show that full-length WWOX physically interacts with EBOV VP40, MARV VP40, and LASV-Z to negatively regulate egress of VLPs and of a live vesicular stomatitis virus-EBOV recombinant virus (M40). Interestingly, WWOX is a versatile host protein that regulates multiple signaling pathways and cellular processes via modular interactions between its WW-domains and PPxY motifs of select interacting partners, including host angiomotin ( AMOT). Notably, we demonstrated recently that expression of endogenous AMOT not only positively regulates egress of VLPs but also promotes egress and spread of live EBOV and MARV. Regarding the mechanism of action, we show that the competitive and modular interplay among WWOX, AMOT, and VP40/Z regulates VLP and M40 virus egress. Thus, WWOX is the newest member of an emerging group of host WW-domain interactors (e. g., BAG3 and YAP/ TAZ) that negatively regulate viral egress. These findings further highlight the complex interplay of virus-host PPxY/ WW-domain interactions and their potential impact on the biology of both the virus and the host during infection. IMPORTANCE Filoviruses (EBOV and MARV) and arenavirus (LASV) are zoonotic, emerging pathogens that cause outbreaks of severe hemorrhagic fever in humans. A fundamental understanding of the virus-host interface is critical for understanding the biology of these viruses and for developing future strategies for therapeutic intervention. Here, we identified host WW-domain-containing protein WWOX as a novel interactor with VP40 and Z and showed that WWOX inhibited budding of VP40/Z VLPs and live virus in a PPxY/WW-domain-dependent manner. Our findings are important to the field as they expand the repertoire of host interactors found to regulate PPxY-mediated budding of RNA viruses and further highlight the competitive interplay and modular virus-host interactions that impact both the virus life cycle and the host cell.

Automated summary

The study identified the host WW-domain-containing protein WWOX as a novel interactor with VP40 and Z proteins, demonstrating that WWOX inhibits budding of VP40/Z VLPs and live virus in a PPxY/WW-domain-dependent manner. These findings expand the repertoire of host interactors regulating PPxY-mediated budding of RNA viruses and highlight competitive interplay and modular virus-host interactions impacting both the virus life cycle and the host cell.