ATP-Binding Cassette Transporter A1 (ABCA1) is a crucial membrane protein involved in the regulation of lipid homeostasis by facilitating the efflux of cholesterol and phospholipids to lipid-poor apolipoproteins, a process essential for the formation of high-density lipoprotein (HDL). Mutations in the ABCA1 gene can lead to Tangier disease and familial HDL deficiency, highlighting its importance in cardiovascular health.