Paramyxovirus accessory proteins target the intracellular viral pathogen-associated molecular patterns (PAMP) signaling pathways. The signaling pathways leading from the RNA helicases mda-5 and RIG-I to IFN-β induction are shown (reviewed in Randall and Goodbourn (2008), Gale and Sen (2009)). As discussed in the text, paramyxovirus V proteins interact with mda-5 and prevent its activation. Sendai virus (SeV) C protein targets RIG-I, although a specific molecular interaction has yet to be shown. The NS2 protein of human respiratory syncytial virus (HRSV) directly binds to RIG-I and inhibits its activity. The V proteins of human parainfluenza virus 2 (HPIV2), simian virus 5 (PIV5, formerly SV5), and mumps virus (MuV) interact with and inhibit TBK1 and IKK-ɛ, and NiV V inhibits IKK-ɛ (although not TBK1). The C protein of rinderpest virus (RPV) and the W protein of Nipah virus (NiV) have uncharacterized nuclear targets that act downstream of transcription factors.