Scavenger receptor class B type 1 and ATP-binding cassette transporter A1 (SR-B1/ABCA1)

Scavenger receptor class B type 1 (SR-B1) and ATP-binding cassette transporter A1 (ABCA1) are essential membrane proteins that drive the reverse cholesterol transport (RCT) pathway, a critical process for maintaining systemic cholesterol homeostasis. ABCA1 serves as the primary gatekeeper of this pathway, facilitating the efflux of cellular cholesterol and phospholipids to lipid-poor apolipoprotein A-I (apoA-I) to form nascent high-density lipoprotein (HDL) particles (UniProt O95477). In contrast, SR-B1 acts as the terminal receptor in the liver, mediating the selective uptake of cholesteryl esters from mature HDL into hepatocytes for biliary excretion (UniProt P50851). Together, these proteins prevent the accumulation of excess cholesterol in peripheral tissues, particularly within the arterial wall, thereby protecting against atherosclerosis and cardiovascular disease (PubMed: 11737167). Pharmacological strategies targeting these proteins include Liver X Receptor (LXR) agonists to upregulate ABCA1 and various small molecules or peptides to modulate SR-B1 activity. However, therapeutic development has been challenged by safety concerns such as hepatic steatosis and the complex relationship between HDL levels and functional cholesterol clearance.

Other names

SCARB1SRB1CD36L1CLA-1ABCA1ABC1TGDCERPHDLDT1

ABCA1 facilitates the efflux of cholesterol and phospholipids to lipid-poor apolipoprotein A-I to form nascent HDL, while SR-B1 mediates the selective uptake of HDL-cholesteryl esters by the liver for biliary excretion.