P-glycoprotein (P-gp)

P-glycoprotein (P-gp) is a 170 kDa transmembrane glycoprotein that functions as an ATP-dependent efflux pump. It plays a crucial role in multidrug resistance and the transport of various substances across cell membranes. Structurally, it has two transmembrane domains and two nucleotide-binding domains that bind and hydrolyze ATP, connected by a flexible linker. Encoded by the MDR1 (ABCB1) gene, P-gp is widely distributed in tissues like the GI tract, blood-brain barrier, liver, and kidney, where it protects against xenobiotics, facilitates excretion, and restricts drug uptake into the brain. Its ability to transport a broad range of substrates with little specificity contributes significantly to multidrug resistance, drug bioavailability, and drug-drug interactions. P-gp's clinical significance is high, particularly in cancer resistance, pharmacokinetics, CNS drug delivery, and transplantation.

Other names

MDR1ABCB1

P-glycoprotein acts as an ATP-dependent efflux pump, actively transporting diverse substrates out of cells against concentration gradients using the energy from ATP hydrolysis.