P-glycoprotein (gene symbol: ABCB1 or MDR1) and Breast cancer resistance protein (gene symbol: ABCG2) (P-gp and BCRP)

P-glycoprotein (P-gp, ABCB1) and Breast cancer resistance protein (BCRP, ABCG2) are **ATP-binding cassette (ABC) efflux transporters** that function as drug pumps, transporting a broad range of xenobiotics and therapeutic drugs out of cells using the energy of ATP hydrolysis[1][2][3][5]. They play pivotal roles in multidrug resistance in cancer by decreasing the intracellular concentrations of anticancer agents, and are expressed in barrier tissues including the intestine, liver, kidney, blood-brain barrier, and placenta, where they protect cells from toxins and modulate absorption and elimination of drugs[1][3][4][5]. Overexpression of these proteins in cancer cells is associated with poor response to chemotherapy. Both are considered major therapeutic targets for overcoming drug resistance in cancer, but inhibition poses safety risks due to altered drug pharmacokinetics and possible loss of protective barrier function[1][5]. **Note**: For structured databases, each should be listed separately: - P-glycoprotein (ABCB1/MDR1) - Breast cancer resistance protein (ABCG2/BCRP) Each has distinct aliases, gene symbols, and drug interaction profiles.

Other names

MDR1ABCB1BCRPABCG2MXRABCP

Drugs may interact as competitive substrates (transported and effluxed), non-competitive inhibitors (block transport), or allosteric modulators[2][3][5]. These pumps utilize ATP hydrolysis to power the efflux of substrates across membranes, decreasing intracellular drug concentrations and thus reducing efficacy of chemotherapeutics[2][3][5].