ATP-binding cassette sub-family B member 1 (P-gp) (P-gp)

ATP-binding cassette sub-family B member 1, commonly known as P-glycoprotein (P-gp) or MDR1, is a prominent member of the ATP-binding cassette (ABC) transporter superfamily that functions as an ATP-dependent efflux pump [1]. It is widely expressed in physiological barriers such as the blood-brain barrier, intestinal epithelium, hepatocytes, and renal proximal tubules, where it protects the body by extruding toxins and xenobiotics [3, 5]. In clinical oncology, the overexpression of MDR1 is a well-documented mechanism of multidrug resistance, as it actively pumps various chemotherapeutic agents out of malignant cells, thereby reducing their intracellular concentration and therapeutic effect [1, 4]. Beyond its role in cancer, MDR1 is a major determinant of the pharmacokinetic profile of many drugs, influencing their absorption, distribution, and elimination [5]. Consequently, it is a primary focus of drug-drug interaction studies, as the inhibition or induction of MDR1 can lead to significant changes in the plasma levels and toxicity of co-administered substrates [3, 5]. Efforts to develop clinical inhibitors to reverse multidrug resistance have faced challenges due to the essential protective roles MDR1 plays in healthy tissues [4].

Other names

Multidrug resistance protein 1MDR1ABCB1CD243P-glycoprotein 1Permeability glycoprotein

ATP-dependent efflux pump that transports a wide variety of structurally diverse substrates from the cytoplasm or lipid bilayer to the extracellular space against a concentration gradient [1, 3].