The complex of ATP-binding cassette sub-family G members 5 and 8 (ABCG5:ABCG8) in the plasma membrane mediates the ATP-dependent export of cytosolic sterols (cholesterol and phytosterols). Mutations affecting the ABCG5/8 proteins are associated with the accumulation of high levels of cholesterol and phytosterols in the body, demonstrating the specificity and physiological importance of this process (Berge et al. 2000). Human ABCG5/8 has not been studied in detail, but the homologous mouse protein complex mediate ATP-dependent sterol export (Wang et al. 2006). The mouse proteins localize to the apical plasma membranes of enterocytes and hepatocytes, consistent with the hypothesis that in vivo ABCG5/8 mediates sterol export into the gut lumen and from hepatocytes into the bile (Graf et al. 2003).
sterol transporter activity of ABCG5:ABCG8 [plasma membrane]