Expression of wt hVKORC1, the mutated di-arginine, and the mutated di-lysine variants. (A) Representative merged overview images for all di-arginine and di-lysine hVKORC1 variants investigated (×40). Human VKORC1 protein is EGFP tagged and green colored, the ER is red fluorescent stained (primary antibody: anti-PDI; secondary antibody: AlexaFluor 594), and the nucleus is counterstained with ToPro3 (blue). (B) The total number of cells expressing the respective hVKORC1 variant per view (×40). Five images of 3 different transfections for each variant were counted. The ratio was normalized to the defined number of 500 cells. Error bars represent the SD.