Molecular Mechanism By Which NEDD4 Acetylation Promotes EBOV VP40 Budding

Ebola virus(EBOV)is one of the most deadly pathogens causing human and primates’ fatal hemorrhagic fever diseases.The 2013–2016 West African epidemic,by far the most geographically extensive,most fatal,and longest lasting epidemic in Ebola’s history,presented an enormous international public health challenge.The new outbreak in the Democratic Republic of Congo,June 2020 makes the virus infected with a very high mortality rate to be concerned by people again.Till now,effective vaccines and drugs against Ebola are few and far between.Therefore,in-depth understanding of the pathogenesis of Ebola virus and its relationship with host cells is particularly important for the development of new vaccines and antiviral drugs.The final stage of Ebola virus replication is viral particles bud from host cells and wherein matrix protein VP40 is essential to drive the formation of viral particles,and its expression alone can form virus-like particles.Many post-translational modifications have been found to regulate the budding of VP40 through different cellular signal transduction mechanisms,such as ubiquitination,sumoylation,and phosphorylation.Recent studies have shown that acetylation plays an important role in the life cycle of the virus,but its role in Ebola virus budding process has not been reported.Therefore,this paper explores the regulation of acetylation in the budding process of Ebola virus.First,after expressing VP40,enhancing the cellular acetylation level could help the release of VP40,suggesting that acetylation positively regulates the budding of Ebola virus.Then,we confirmed that VP40 had acetylation modification in cells,but the mutation of its acetylation site had no effect on the budding of the virus.Therefore,we speculated that the increased acetylation level of cytokines interacting with VP40 in host cells indirectly helped the budding of VP40.E3 ubiquitin ligase NEDD4 is the first reported host protein that interacts with VP40 to ubiquitinate and promote VP40 budding.We found that acetylation of NEDD4 K667 catalyzed by acetyltransferase P300 positively regulated the budding of VP40:1 Acetylation of NEDD4 helps VP40 migrate to the cell membrane and increases the formation of VP40 pseudopodia structure on the cell membrane.2 Acetylation of NEDD4 enhanced the interaction with VP40 and increased itself E3 ubiquitin ligase.3 Acetylation of NEDD4 enhanced ubiquitination of VP40,ultimately contributing to the release of VP40.In summary,this study clarified for the first time the role of NEDD4 acetylation in the budding process of Ebola virus,and supplemented the research on posttranslational modification of protein in the budding process of Ebola virus.