Subcellular localization of HA-tagged ABCA1 variants in polarized MDCKII cells. MDCKII cells expressing the wild type (D-F) or mutant variants (G-O) of HA-ABCA1 were grown on a permeable membrane support to form polarized cultures. As a negative control, cells transduced with the neo-containing vector (see Figure 1) were used (A-C). HA-ABCA1 variants were visualized by immunofluorescent staining of permeabilized cells, using confocal microscopy. ABCA1 protein detected by anti-HA antibody is shown in green; staining of Na+/K+ ATPase (red) served as a basolateral plasma membrane marker. Right panels depict the overlay. Cross sections are shown at the bottom of each panel; arrows at the side indicate the position of the presented xz and xy planes. All HA-tagged ABCA1 variants exhibited similar and clear basolateral plasma membrane localization, showing only a low level intracellular staining.