VRK1 and infection: To further examine the impact of VRK1 on B12 localization, we compared the localization of HA-B12 during infection using cells lacking VRK1 (VRK1KO-CTRL) or cells expressing either nuclear VRK1 (VRK1KO-VRK1 WT) or cytoplasmic VRK1 (VRK1KO-VRK1 ΔNLSΔBasic).