Plays a major role in antagonizing the type I IFN-mediated antiviral response (PubMed:15047850). Acts cooperatively with NS1 to repress activation and nuclear translocation of host IFN-regulatory factor IRF3 (PubMed:15827150). Interacts with the host cytoplasmic sensor of viral nucleic acids DDX58/RIG-I and prevents the interaction with its downstream partner MAVS (PubMed:19193793). Together with NS2, participates in the proteasomal degradation of host STAT2, IRF3, IRF7, TBK1 and DDX58 through a NS-degradasome involving CUL2 and Elongin-C (PubMed:17251292, PubMed:23877405). The degradasome requires an intact mitochondrial MAVS (PubMed:23877405). Induces host SOCS1 expression (PubMed:26557722). Induces activation of NF-kappa-B. Suppresses premature apoptosis by an NF-kappa-B-dependent, interferon-independent mechanism promoting continued viral replication (PubMed:17151097). Monomer (instable) (PubMed:8864205). Homomultimer (PubMed:8864205). Heteromultimer with NS1 (PubMed:21795342). Interacts with host DDX58 (via N-terminus); this interaction prevents host signaling pathway involved in interferon production (PubMed:19193793). Interacts with host MAP1B/microtubule-associated protein 1B (PubMed:21795342). Most NS2 resides in the mitochondria as a heteromer with NS1. The DNLP motif has IFN suppressive functions like binding to host MAP1B. Belongs to the pneumovirus non-structural protein 2 family.