Multiomics approach reveals the ubiquitination-specific processes hijacked by SARS-CoV-2

The Coronavirus Disease 2019(COVID-19)caused by Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)is a global pandemic that seriously threatens health and socioeconomic development,but the existed antiviral drugs and vaccines still cannot yet halt the spread of the epidemic.Therefore,a comprehensive and profound understanding of the pathogenesis of SARS-CoV-2 is urgently needed to explore effective therapeutic targets.Here,we conducted a multiomics study of SARS-CoV-2-infected lung epithelial cells,including transcriptomic,proteomic,and ubiquitinomic.Multiomics analysis showed that SARS-CoV-2-infected lung epithelial cells activated strong innate immune response,including interferon and inflammatory responses.Ubiquitinomic further reveals the underlying mechanism of SARS-CoV-2 disrupting the host innate immune response.In addition,SARS-CoV-2 proteins were found to be ubiquitinated during infection despite the fact that SARS-CoV-2 itself didn’t code any E3 ligase,and that ubiquitination at three sites on the Spike protein could significantly enhance viral infection.Further screening of the E3 ubiquitin ligases and deubiquitinating enzymes(DUBs)library revealed four E3 ligases influencing SARS-CoV-2 infection,thus providing several new antiviral targets.This multiomics combined with high-throughput screening study reveals that SARS-CoV-2 not only modulates innate immunity,but also promotes viral infection,by hijacking ubiquitination-specific processes,highlighting potential antiviral and anti-inflammation targets.

SARS-CoV-2 helicase NSP13 hijacks the host protein EWSR1 to promote viral replication by enhancing RNA unwinding activity

Background:Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)emerged in December 2019 and has led to a global coronavirus disease 2019(COVID-19)pandemic.Currently,incomplete understanding of how SARS-CoV-2 arrogates the host cell to establish its life cycle has led to slow progress in the development of effective drugs.Results:In this study,we found that SARS-CoV-2 hijacks the host protein EWSR1(Ewing Sarcoma breakpoint region 1/EWS RNA binding protein 1)to promote the activity of its helicase NSP13 to facilitate viral propagation.NSP13 is highly conserved among coronaviruses and is crucial for virus replication,providing chemical energy to unwind viral RNA replication intermediates.Treatment with different SARS-CoV-2 NSP13 inhibitors in multi-ple cell lines infected with SARS-CoV-2 effectively suppressed SARS-CoV-2 infection.Using affinity-purification mass spectrometry,the RNA binding protein EWSR1 was then identified as a potent host factor that physically associated with NSP13.Furthermore,silencing EWSR1 dramatically reduced virus replication at both viral RNA and protein levels.Mechanistically,EWSR1 was found to bind to the NTPase domain of NSP13 and potentially enhance its dsRNA unwinding ability.Conclusions:Our results pinpoint EWSR1 as a novel host factor for NSP13 that could potentially be used for drug repurposing as a therapeutic target for COVID-19.