P-gp, also called MDR1 or ABCB1, is a glycoprotein that in humans is encoded by the ABCB1 gene. P-gp is a well-characterized ABC-transporter (which transports a wide variety of xenobiotics across extra- and intracellular membranes). It is an ATP-dependent drug efflux pump with broad substrate specificity. It is responsible for decreased drug accumulation in multidrug-resistant cells and often mediates the development of resistance to anticancer drugs. This protein functions in the kidneys, liver, blood
