Fig. 1.

Intracellular signaling of the IIR via the IRF3 and RelA effectors. For an idealized AEC, the intracellular RIG-I and endosomal TLR3 PRRs in response to intracellular dsRNA are shown. Downstream of the PRR signaling complexes, the typical IκB kinase (IKKα/β) and atypical IKK (IKKι/TBK1) trigger phosphorylation and nuclear translocation of the NFκB/RelA and IRF3 transcription factors, representing the primary effector arms of the IIR. The 2 pathways are coupled by positive cross-talk via the NFκB-dependent activation of IRF7, involved in amplification of RIG-I-IFN production and negative RelA-IRF3 cross-talk. pRelA = Phospho-RelA.