KPNA2 and infection: As A55 is a predicted BBK E3 ligase adaptor, the levels of KPNA2 following infection with the WT VACV WR strain expressing A55 (vA55), a mutant lacking the A55R gene (vΔA55), or a revertant virus with A55R inserted back into vΔA55 and under its endogenous promoter (vΔA55Rev) were investigated.