SARS-CoV-2 PLpro negatively regulates interferon-β immune pathway induced by DDX3
Objective To discover the host factor interacting with severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)papain-like protease(PLpro)and explore the potential mechanism.Methods The second-generation proximity-dependent biotin identification(BioID2)approach combined with mass spectrometry analysis was used to search for the potential host factors.Immunofluorescence and co-immunoprecipitation(Co-IP)assay were used to verify the interactions between DEAD-box helicase 3(DDX3)and PLpro.The influence of PLpro on DDX3-inhibitor of kappa B kinase ε(IKKε)-TANK-binding kinase 1(TBK1)and DDX3-mitochondrial antiviral signaling protein(MAVS)complexes was also investigated by Co-IP.The effect of PLpro on interferon-β(IFN-β)immune pathway and the protease activity on substrates were studied via luciferase activity assay.Results DDX3 could co-locate and interact with PLpro intracellularly.PLpro might possibly inhibit both the formation of DDX3-MAVS complex and the interactions between DDX3-IKK-ε-TBK1.PLpro could negatively regulate type Ⅰ interferon pathway.Overexpression of DDX3 could lead to a significant increase in the cleavage activity of PLpro/PLP-TM that might be significantly decreased in case of inventions with DDX3 expressions.Conclusion DDX3 may be one of the host factors that interact with SARS-CoV-2 PLpro.PLpro negatively regulates IFN-β immune pathway induced by DDX3,which may provide a favorable immune environment for virus replication.
severe acute respiratory syndrome coronavirus-2papain-like proteaseDEAD-box helicase 3antiviral innate immunity
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