Substrate Transport is Mediated not only by P-glycoprotein but also by Lipid Penetration

Abstract

In association with large-scale conformational changes, the members of the ATP-binding cassette (ABC) transporter superfamily such as P-glycoprotein (P-gp) pump endogenous cytotoxic substances and exogenous drugs out of cells. Here, a series of nonequilibrium-driven molecular dynamics (MD) simulations are sophisticatedly combined to provide a generally effective access to quantitatively investigate such a complex biological process that has been posing a great challenge for experiments and computational simulations. Both common features and unique characteristics of multiple ligands (substrates or inhibitors) that are recognized by P-gps from mouse and human species are quantitatively explored, providing additional insights into experimentally suggested ligand transport pathways and summarizing the important roles of not only different P-gps but also lipids in regulating ligand transport. These findings reveal the molecular mechanism underlying the transport of ligands by P-gps from different species and emphasize the consideration of lipid effects on the future design of effective P-gp inhibitors.