ATP-binding cassette sub-family G member 5 (ABCG5) (ABCG5)

ATP-binding cassette sub-family G member 5 (ABCG5), also known as sterolin-1, is a half-transporter that must form a heterodimer with ABCG8 to become functionally active (UniProt: Q9H222). This complex is primarily expressed in the apical membranes of enterocytes and hepatocytes, where it plays a critical role in maintaining whole-body sterol homeostasis by mediating the ATP-dependent efflux of dietary sterols and cholesterol (NCBI Gene: 64240). Its primary biological function is to limit the intestinal absorption of plant sterols and promote the biliary excretion of cholesterol into the bile (PubMed: 11138003). Mutations in the ABCG5 gene lead to sitosterolemia, a rare autosomal recessive disorder characterized by the accumulation of plant sterols in the blood and tissues, which significantly increases the risk of premature atherosclerosis and xanthomas (PubMed: 11137994). While no drugs currently target ABCG5 directly in clinical practice, its expression is highly inducible by Liver X Receptor (LXR) agonists, making it a key pathway for research into lipid-lowering therapies and reverse cholesterol transport (PubMed: 12554753).

Other names

Sterolin-1ABC transporter G5STSL

The ABCG5/ABCG8 heterodimer functions as a sterol efflux pump, utilizing ATP hydrolysis to transport cholesterol and non-cholesterol sterols (phytosterols) across the apical membrane of hepatocytes into the bile and from enterocytes back into the intestinal lumen (UniProt: Q9H222).