Abstract
Drug transporters recognize diverse drugs as substrate and play an important role as determinants of systemic circulation and tissue distribution of drugs in vivo. They are comprised of the members of Solute carrier （SLC） family （SLCO, SLC22, SLC47） and ATP binding cassette family （ABCB1, ABCC2, ABCC4, and ABCG2）. In this article, we introduce recent topics in drug transporter research, including our laboratory. （1） The three-dimensional structures of multispecific organic anion transporters in the liver, OATP1B1 and OATP1B3, have been solved that aid deep understanding of the mechanism for recognizing diverse compounds as substrates and suggest the driving force for active transport. （2） Cells derived from human tissues are indispensable to investigate roles of drug transporters in vitro. Microphysiological systems （or complex in vitro systems） that mimic human organ physiology have emerged and advanced in vitro models for ADME studies. Stem cells in the crypt of gut can differentiate to various cells including absorptive epithelial cells for in vitro drug transport and metabolism analysis. （3） Substrates of drug transporters includes endogenous metabolites whose plasma concentrations or renal clearance is tightly associated with the activities of drug transporters. They are considered as endogenous biomarkers to detect the variation in drug transporter activities in humans who receive administration of drugs that has potential to inhibit transporters at their clinically relevant doses.
