PIAS1 and viral infectious disease: Most of the NP was localized in the cytoplasm at 2 h p.i., accumulated in the nucleus at 4 h p.i., was exported to the cytoplasm at 6 h p.i., and gathered around the plasma membrane at 8 h p.i. Of note, PIAS1 partially colocalized with NP during the shuttle of NP between the cytoplasm and nucleus at different stages of virus infection.