ABCB1 (ATP Binding Cassette Subfamily B Member 1)
Multidrug Resistance Protein 1 (MDR1) – Pharmacogenomics and Cancer Drug Resistance
Gene Information Card
| Symbol | ABCB1 |
|---|---|
| Full Name | ATP Binding Cassette Subfamily B Member 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 7q21.12 |
| NCBI Gene ID | 5243 ncbi.nlm.nih.gov/gene/5243 |
| Ensembl ID | ENSG00000085563 |
| UniProt ID | P08183 |
| OMIM ID | 171050 |
| HGNC ID | 40 |
| Aliases | MDR1, P-gp, PGY1, ABC20, CD243 |
Description
ABCB1 encodes P-glycoprotein (P-gp), an ATP-dependent efflux transporter of the ATP-binding cassette (ABC) superfamily. It is expressed on the apical membrane of epithelial cells in the intestine, liver, kidney, and blood-brain barrier, and actively exports a wide range of xenobiotics and drugs, including chemotherapeutics (e.g., doxorubicin, paclitaxel, vinca alkaloids). Overexpression in tumor cells is a major mechanism of multidrug resistance (MDR). Polymorphisms in ABCB1 (e.g., C3435T, G2677T/A) affect drug disposition, efficacy, and toxicity.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Multidrug resistance in cancer | Overexpression of P-gp reduces intracellular accumulation of chemotherapeutic agents | ClinVar, COSMIC |
| Inflammatory bowel disease (IBD) | Altered ABCB1 expression affects intestinal barrier function and drug response | NCBI, OMIM |
| Epilepsy drug resistance | P-gp overexpression at the blood-brain barrier limits CNS penetration of antiepileptic drugs | ClinVar |
| HIV/AIDS | ABCB1 polymorphisms influence protease inhibitor pharmacokinetics and viral suppression | NCBI |
| Cholestasis | Impaired ABCB1 function disrupts bile acid transport | OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 58.2 | High |
| Small intestine | 45.1 | High |
| Kidney | 32.7 | High |
| Colon | 28.4 | High |
| Brain (blood-brain barrier) | 12.3 | Medium |
| Adrenal gland | 10.5 | Medium |
| Lung | 3.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Caco-2 | 45.0 | Intestinal epithelial model |
| HepG2 | 38.5 | Hepatocellular carcinoma |
| MCF-7 | 2.1 | Low baseline; inducible |
| KB-3-1 | 1.5 | Drug-sensitive; low P-gp |
| KB-V1 | 120.0 | Multidrug-resistant variant; high P-gp |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.3435C>T (rs1045642) | SNP | ~50% (global) | Alters mRNA stability; associated with altered drug transport |
| c.2677G>T/A (rs2032582) | SNP | ~40% (global) | Missense (Ala893Ser/Thr); affects substrate specificity |
| c.1236C>T (rs1128503) | SNP | ~35% (global) | Silent; linked to expression changes |
| p.Gly185Val | Missense | Rare | Reduced transport activity in vitro |
| p.Ser400Asn | Missense | Rare | Altered ATPase activity |
Mutation functional classification
Loss of Function (LOF)
Rare missense variants (e.g., p.Gly185Val) reduce efflux activity, increasing drug sensitivity.
Gain of Function (GOF)
Not well characterized; some SNPs (e.g., c.3435T) may increase expression or activity in specific contexts.
Dominant Negative (DN)
No confirmed dominant-negative mutations reported.
View complete mutation data：
Gene Ontology (GO)
| • ATP binding (GO:0005524) | • ATPase activity (GO:0016887) |
| • xenobiotic transmembrane transporter activity (GO:0008559) | • drug transmembrane transport (GO:0006855) |
| • cellular response to drug (GO:0035690) | • apical plasma membrane (GO:0016324) |
Pathways
• ABC transporters (KEGG hsa02010)
• Drug metabolism - other enzymes (KEGG hsa00983)
• Multidrug resistance (Reactome R-HSA-382556)
Protein Summary
P-glycoprotein (P-gp) is a 170 kDa transmembrane efflux pump composed of two homologous halves, each containing six transmembrane domains and a nucleotide-binding domain (NBD). It utilizes ATP hydrolysis to transport a broad spectrum of hydrophobic compounds out of cells. P-gp is critical in pharmacokinetics, limiting oral absorption and brain penetration of drugs. Its overexpression in cancer cells confers multidrug resistance, a major obstacle to chemotherapy. Structural studies reveal a large, flexible drug-binding pocket that accommodates diverse substrates.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| ABCB11 Knockout HEK293 Cell Line | EDJ-KQ2032 | Human | 8647 | Details Get a Quote |
| ABCB1 Knockout HEK293 Cell Line | EDC07523 | Human | 5243 | Details Get a Quote |
| ABCB10 Knockout HEK293 Cell Line | EDJ-KQ8016 | Human | 23456 | Details Get a Quote |
| ABCB1 Knockout HCT 116 Cell Line | EDJ-KQ25396 | Human | 5243 | Details Get a Quote |
| ABCB1 Knockout HeLa Cell Line | EDJ-KQ25397 | Human | 5243 | Details Get a Quote |
| ABCB10 Knockout A-549 Cell Line | EDJ-KQ33778 | Human | 23456 | Details Get a Quote |
| ABCB10 Knockout HCT 116 Cell Line | EDJ-KQ33779 | Human | 23456 | Details Get a Quote |
| ABCB10 Knockout HeLa Cell Line | EDJ-KQ33780 | Human | 23456 | Details Get a Quote |
| ABCB11 Knockout HeLa Cell Line | EDJ-KQ54969 | Human | 8647 | Details Get a Quote |
| ABCB1 Knockout A-549 Cell Line | EDJ-KQ62621 | Human | 5243 | Details Get a Quote |
| ABCB11 Knockout A-549 Cell Line | EDJ-KQ63451 | Human | 8647 | Details Get a Quote |
| ABCB11 Knockout HCT 116 Cell Line | EDJ-KQ71919 | Human | 8647 | Details Get a Quote |
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