To understand the interaction between TBK1 or TBK1 isoforms and endogenous IRF3 protein in response to viral infection, EPC cells were transfected with p3 × FLAG, TBK1-FLAG, TBK1_tv1-FLAG, or TBK1_tv2-FLAG, and then infected with SVCV. Here, TBK1 is linked to viral infectious disease.