ATP-binding cassette subfamily G member 2 (ABCG2)

ATP-binding cassette subfamily G member 2 (ABCG2) is a membrane-associated protein belonging to the ATP-binding cassette (ABC) transporter superfamily[1][4][2][3]. As a "half transporter," it requires homodimerization for activity, and is located predominantly on apical membranes of epithelial cells in tissues including the intestine, liver, placenta, blood–brain barrier, testis, and kidney[1][4][3]. ABCG2 uses energy derived from ATP binding and hydrolysis to actively pump a broad spectrum of substrates—including drugs, metabolites, and xenobiotics—out of cells against concentration gradients, helping to mediate physiological protection (e.g., blocking drug absorption, protecting fetuses, exporting vitamins into milk, and excreting urate)[1][7][8]. Also known as breast cancer resistance protein (BCRP), ABCG2 is best known for its role in multidrug resistance, where its overexpression in tumors confers resistance to various chemotherapeutic agents[1][3][4]. Loss-of-function mutations in ABCG2 can cause hyperuricemia and gout by impairing renal and intestinal urate excretion[7]. ABCG2 is recognized as a clinically significant target and biomarker in both cancer and metabolic disease contexts[1][3][7].

Other names

Breast cancer resistance protein (BCRP)CDw338 (cluster of differentiation w338) / CD338Mitoxantrone resistance-associated protein (MXR)ATP-binding cassette transporter G2ABCPBCRP1Placenta-specific ATP-binding cassette transporterJr blood group protein

Drug efflux by ATP-dependent active transport, preventing intracellular accumulation of substrates, including chemotherapeutic agents and metabolites