P-glycoprotein 1 (P-gp) (P-gp)

P-glycoprotein 1 (P-gp), also known as Multidrug resistance protein 1 (MDR1), is a member of the ATP-binding cassette (ABC) transporter superfamily that functions as an ATP-dependent efflux pump (UniProt P08183). It is widely expressed in physiological barriers such as the intestinal epithelium, the blood-brain barrier, and the renal tubules, where it limits the absorption and promotes the excretion of various xenobiotics and drugs (StatPearls, 2023). P-gp plays a pivotal role in the pharmacokinetics of dabigatran etexilate, a direct oral anticoagulant; since dabigatran etexilate is a substrate of P-gp, its bioavailability is heavily dependent on the transporter's activity (FDA Pradaxa Label). Inhibition of P-gp by drugs like verapamil or amiodarone can significantly increase dabigatran exposure, raising the risk of major bleeding, whereas P-gp inducers like rifampin can reduce its plasma levels and compromise its antithrombotic efficacy (PubMed, 2014). Beyond its role in drug-drug interactions, P-gp is a major factor in multidrug resistance in cancer, as it pumps chemotherapeutic agents out of malignant cells (NIH, 2022).

Other names

Multidrug resistance protein 1MDR1ATP-binding cassette sub-family B member 1ABCB1CD243Cluster of Differentiation 243

ATP-dependent efflux pump that transports substrates across cellular membranes against a concentration gradient.