SDC4 and viral infectious disease: As shown in Fig. 4e,f, Flag-RIG-I(N) overexpression inhibited VSVΔM51-GFP replication, which is consistent with its antiviral role, whereas co-expression with SDC4 rendered the cells more susceptible to viral infection, suggesting that SDC4 negatively regulates the RIG-I-mediated antiviral signalling pathway.