Function and regulation of ABCA1--membrane meso-domain organization and reorganization.

The ATP-binding cassette protein A1 (ABCA1) mediates the secretion of cellular-free cholesterol and phospholipids to an extracellular acceptor, apolipoprotein A-I, to form high-density lipoprotein. Because ABCA1 is a key factor in cholesterol homeostasis, elaborate transcriptional and post-transcriptional regulations of ABCA1 have evolved to maintain cholesterol homeostasis. Recent studies suggest that ABCA1 moves lipids not only between membranes but also within membranes to organize and reorganize membrane meso-domains to modulate cell proliferation and immunity.