Inter-Fighting between Influenza A Virus NS1 and β-TrCP: A Novel Mechanism of Anti-Influenza Virus

Influenza A virus (IAV) prevents innate immune signaling during infection. In our previous study, the production of pro-inflammatory cytokines was associated with Cullin-1 RING ligase (CRL1), which was related to NF-kappa B activation. However, the underlying mechanism is unclear. Here, an E3 ligase, beta-transducin repeat-containing protein (beta-TrCP), was significantly downregulated during IAV infection. Co-IP analysis revealed that non-structural 1 protein (NS1) interacts with beta-TrCP. With co-transfection, an increase in NS1 expression led to a reduction in beta-TrCP expression, affecting the level of I kappa B alpha and then resulting in repression of the activation of the NF-kappa B pathway during IAV infection. In addition, beta-TrCP targets the viral NS1 protein and significantly reduces the replication level of influenza virus. Our results provide a novel mechanism for influenza to modulate its immune response during infection, and beta-TrCP may be a novel target for influenza virus antagonism.