Promotes the proteasomal degradation of host EIF2AK2/PKR but is unable to suppress host general transcription (PubMed:23325696). Prevents the establishment of the host antiviral state by interfering with beta interferon (IFN-beta) production. Interacts with host DDX58/RIG-I and targets it for proteasomal degradation, thereby inhibiting DDX58-mediated signaling pathway (PubMed:23552410). Interacts with host DDX58; this interaction targets DDX58 to proteasomal degradation (PubMed:23552410). Interacts with host EIF2AK2/PKR; this interaction leads to the proteasomal degradation of host EIF2AK2/PKR (PubMed:23325696). Belongs to the phlebovirus NS-S protein family.