ABCA3-mediated choline-phospholipids uptake into intracellular vesicles in A549 cells

ABCA3 is proposed to function as a lung surfactant lipid transporter. Here we report ABCA3-dependent lipid uptake into intracellular vesicles in lung adenocarcinoma A549 cells. A549 cells stably expressing GFP-tagged wild-type ABCA3 (A549/ABCA3WT) had larger LAMP3-positive vesicles than their parental cells as well as A549 cells expressing a Walker A motif mutant (A549/ABCA3N568D). The choline-phospholipids level in A549/ABCA3WT was increased 1.25-fold compared to that in A549 and A549/ABCA3N568D cells, while the cholesterol levels were similar. Sucrose gradient fractionation analysis in A549/ABCA3WT cells revealed that choline-phospholipids were enriched in low-density and nile red-positive vesicles. Electronmicroscopic analysis showed multilamellar vesicles in A549/ABCA3WT cells. These results indicate that ABCA3 mediates ATP-dependent choline-phospholipids uptake into intracellular vesicles.