The TBK1 kinase is involved in the signaling pathway leading to establishment of antiviral state in infected cells. Upon recognition of a virus by TLRs, the signal is transmitted to TBK1. In turn, the active complex phosphorylates and activates IRF3 and IRF7. Once phosphorylated, IRF3 and IRF7 homodimerize and translocate in the nucleus to drive transcription of interferons.
Many viral proteins interact with components of this complex and subsequently inhibit phosphorylation and activation of downstream partners IRF3 and IRF7. Among them, Ebola virus VP35 and Borna virus P protein directly interacts with TBK1. Instead, the poxvirus K7R and hepatitis B virus polymerase prevent TBK1 -IKKe activation of IRF3 and IRF7 by targeting host DDX3 protein, also found present in this complex.