To the Editor: In a recent article in this journal entitled “LXR-Induced Redistribution of ABCG1 to Plasma Membrane in Macrophages Enhances Cholesterol Mass Efflux to HDL”, Nan Wang and colleagues showed that in nonstimulated macrophages ABCG1 protein is predominantly intracellular, and that on treatment with a synthetic liver X-receptor (LXR) ligand it increased in amount and appeared to relocate from this intracellular pool to the plasma membrane.1 Based on our findings outlined below, we suggest an alternative interpretation of these results. Experiments performed in our laboratory showed that transiently expressed N-terminally EGFP-tagged ABCG1 fusion protein localized in the Golgi apparatus and in intracellular vesicles of epithelial HeLa cells a few hours after transfection. Then, between 6 and 24 hours after transfection, increasing amounts of EGFP-ABCG1 appeared in the plasma …