ATP-binding cassette sub-family G member 2 (ABCG2) (ABCG2)

ABCG2 (ATP-binding cassette sub-family G member 2), widely known as Breast Cancer Resistance Protein (BCRP), is a critical half-transporter that functions as a homodimer to mediate the efflux of a broad spectrum of endogenous and exogenous compounds [1, 3]. It is strategically expressed in the apical membranes of the intestine, liver, and kidney, as well as in pharmacological barriers like the blood-brain barrier and placenta, where it serves a protective role by limiting the systemic absorption and promoting the excretion of toxins [6, 10]. In the context of oncology, ABCG2 is a major driver of multidrug resistance (MDR), as it actively pumps out various chemotherapeutic agents, including mitoxantrone and camptothecin analogs, thereby reducing their intracellular concentration and therapeutic efficacy [2, 5]. Beyond its pharmacological impact, ABCG2 is the primary transporter responsible for the extra-renal secretion of urate; genetic variants such as the Q141K polymorphism significantly impair its function, leading to elevated serum uric acid levels and a high risk of gout [7, 10]. For biotech analysts, ABCG2 is a key focus for both overcoming chemoresistance in cancer and managing complex drug-drug interactions in general medicine [11, 12].

Other names

Breast cancer resistance protein (BCRP)Mitoxantrone resistance-associated protein (MXR)Placenta-specific ABC transporter (ABCP)CD338Urate exporter

ABCG2 acts as a primary active efflux transporter that utilizes the energy derived from ATP hydrolysis to pump a diverse range of substrates out of the cytoplasm across the plasma membrane [1, 8].