Combined with the decrease in HCV titers observed upon depletion of Kap β3/IPO5 (Figure 5B and 5D), the decrease in HCV titers following treatment of infected cells with NLS peptides provides further evidence that the nuclear transport pathways are important for viral infection and that, like Nups, different Kaps may contribute to distinct stages in the viral life cycle. This evidence concerns the gene IPO5 and viral infectious disease.