ABCA1 and Tangier disease: To test if the lipid floppase activity (outward translocation across the plasma membrane) of ABCA1 is required for increased cholesterol release in Miltefosine treated cells, we used HEK293 cells stably expressing WT-ABCA1 isoform or a Tangier disease double mutant W590S-C1477R-ABCA1 isoform.