CUL1 and viral infectious disease: We first validated the initially observed interactions (Fig 1D) between NSP1 and Rbx1, Cul1, Cul3 and β-TrCP by co-immunoprecipitation (IP) of transiently overexpressed NSP1s, Rbx1 and Cul3 and in the context of virus infection (Fig 2A–2C).