ABCG8
ATP Binding Cassette Subfamily G Member 8
Gene Information Card
| Symbol | ABCG8 |
|---|---|
| Full Name | ATP Binding Cassette Subfamily G Member 8 |
| Gene Type | protein-coding |
| Chromosomal Location | 2p21 |
| NCBI Gene ID | 64241 ncbi.nlm.nih.gov/gene/64241 |
| Ensembl ID | ENSG00000143921 |
| UniProt ID | Q9H221 |
| OMIM ID | 605460 |
| HGNC ID | 13887 |
| Aliases | STERDAN, G8, sterolin-2 |
Description
ABCG8 encodes a member of the ATP-binding cassette (ABC) transporter superfamily. It forms a heterodimer with ABCG5 to function as a sterol efflux transporter, limiting intestinal absorption and promoting biliary excretion of plant sterols and cholesterol. Mutations in ABCG8 cause sitosterolemia, a rare autosomal recessive disorder characterized by hyperabsorption of phytosterols and premature atherosclerosis. Common variants are also associated with gallstone disease (cholelithiasis).
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Sitosterolemia | Loss-of-function mutations in ABCG8 impair sterol efflux, leading to accumulation of plant sterols in plasma and tissues. | OMIM #210250; ClinVar |
| Gallstone disease (cholelithiasis) | Common variants (e.g., rs11887534, D19H) alter cholesterol transport efficiency, increasing biliary cholesterol saturation and stone formation. | PMID: 17293864; ClinVar |
| Hypercholesterolemia, susceptibility to | Dysfunctional ABCG8/ABCG5 heterodimer reduces cholesterol excretion, contributing to elevated plasma cholesterol levels. | OMIM; PMID: 12442288 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.3 | Medium |
| Small intestine | 8.7 | Medium |
| Colon | 5.1 | Low |
| Gallbladder | 4.2 | Low |
| Kidney | 1.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 10.2 | Hepatocellular carcinoma cell line |
| Caco-2 | 7.8 | Colorectal adenocarcinoma cell line |
| HT-29 | 4.5 | Colorectal adenocarcinoma cell line |
| HEK 293 | 0.3 | Embryonic kidney cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1256G>A (p.Arg419His) | Missense | Rare | Loss of sterol transport activity; associated with sitosterolemia |
| c.1169G>A (p.Arg390Gln) | Missense | Rare | Impaired heterodimerization with ABCG5; sitosterolemia |
| c.1186G>A (p.Asp396Asn) | Missense | Rare | Reduced cell surface expression; sitosterolemia |
| rs11887534 (D19H) | Missense | Common (5-10% in Europeans) | Increased risk of gallstone disease; gain of function in cholesterol transport |
Mutation functional classification
Loss of Function (LOF)
Most sitosterolemia-associated mutations (e.g., Arg419His, Arg390Gln) result in loss of sterol efflux activity due to impaired protein folding, trafficking, or heterodimer formation.
Gain of Function (GOF)
The D19H variant (rs11887534) is considered a gain-of-function allele, enhancing cholesterol transport and increasing biliary cholesterol secretion, predisposing to gallstones.
Dominant Negative (DN)
No well-characterized dominant-negative mutations have been reported for ABCG8.
View complete mutation data：
Gene Ontology (GO)
| • GO:0005242 - ATP-gated monoatomic ion channel activity | • GO:0005319 - lipid transporter activity |
| • GO:0015431 - ABC-type sterol transporter activity | • GO:0016021 - integral component of membrane |
| • GO:0042493 - response to drug | • GO:0042632 - cholesterol homeostasis |
| • GO:0055085 - transmembrane transport |
Pathways
• REACT:191273 - Cholesterol metabolism
• REACT:191299 - Transport of dietary sterols
• REACT:191301 - ABC transporter-mediated sterol efflux
• KEGG: hsa04976 - Bile secretion
Protein Summary
ABCG8 is a 673-amino acid transmembrane protein with an N-terminal nucleotide-binding domain (NBD) and six transmembrane helices. It functions as an obligate heterodimer with ABCG5, localized to the apical membrane of hepatocytes and enterocytes. The complex mediates the efflux of cholesterol and plant sterols into bile and intestinal lumen, respectively. Defects cause sitosterolemia, and common variants modulate gallstone risk.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| ABCG8 Knockout HEK293 Cell Line | EDJ-KQ12247 | Human | 64241 | Details Get a Quote |
| ABCG8 Knockout HeLa Cell Line | EDJ-KQ57047 | Human | 64241 | Details Get a Quote |
| ABCG8 Knockout A-549 Cell Line | EDJ-KQ65555 | Human | 64241 | Details Get a Quote |
| ABCG8 Knockout HCT 116 Cell Line | EDJ-KQ73986 | Human | 64241 | Details Get a Quote |
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