Abstract
ABCA1 (ATP–binding cassette protein A1) is a membrane protein which is essential for the formation of highdensity lipoprotein (HDL). ABCA1 is known to transfer cellular cholesterol and phospholipids to an extracellular lipid acceptor, apolipoprotein A–I (apoA–I) for forming discoidal HDL particles. However, the regulatory mechanisms are still poorly understood. In this review, the application of a new methodology, single-molecule imaging, for observing ABCA1 molecules in the plasma membrane of living cell is described.
