Cellbiological Analysis of the Mechanism of HDL Formation by ABCA1

The ATP-binding cassette protein A1 (ABCA1) mediates the secretion of cellular cholesterol and phospholipids to apolipoprotein A-I (apoA-I) to form high-density lipoprotein (HDL). By using cellbiological approaches and several mutants, we showed that ABCA1 functions as “apoA-I receptor” and “lipid transporter” and both functions are necessary to the HDL formation. From these results, we proposed a novel HDL formation model.