Reaction: Defective ABCG8 (in ABCG5:ABCG8) does not transport sterols from cytosol to extracellular region
- in pathway: Defective ABCG8 causes GBD4 and sitosterolemia
ATP-binding cassette sub-family G member 8 (ABCG8 aka sterolin-2), is a "half transporter", that forms a complex with another half transporter ABCG5 in the endoplasmic reticulum. This complex translocates to the plasma membrane to mediate the ATP-dependent intestinal absorption and facilitation of biliary secretion of cholesterol and phytosterols (eg sitosterol). Defects in either of these half transporters result in loss of enterocyte discrimination between cholesterol and sitosterol causing sterol accumulation and predisposition for atherosclerosis. Defects in ABCG8 are the cause of gallbladder disease 4 (GBD4; MIM:611465) and sitosterolemia (MIM:210250). A mutation causing GBD4 is D19H (Buch et al. 2007). Mutations causing sitosterolemia include W361*, G574R, Y658*, R263Q and P231T (Berge et al. 2000).
Reaction - small molecule participants:
H2O [cytosol]
ATP [cytosol]
Reactome.org reaction link: R-HSA-5679101
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Reaction input - small molecules:
water
ATP(4-)
Reaction output - small molecules:
Reactome.org link: R-HSA-5679101