Membrane transporters regulate their substrates’ intra- and extracellular concentration. They are significant players in various biological events, especially if their substrates are essential for our life. However, substrates are unchanged when they bind to or interact with transporters, but only their biodistribution in the local area can change. Therefore, it is not easy to determine membrane transporters' function under physiological conditions, unlike enzymes, whose substrates are structurally changed. In our body, there are many membrane transporters comparable to enzymes and receptors. Nevertheless, in most of them, functions and physiological significance remain unclear. You realize how important membrane transporters are when you see that sodium-dependent glucose transporter 2 (SGLT2) and apical-dependent bile acid transporter (ASBT) inhibitors have been marketed. In our laboratory, we are interested in membrane transporters that recognize amino acids and lipids because their biodistributions are closely related to the molecular basis of chronic inflammation and cancers. Our laboratory aims to find a new link between membrane transporters and human diseases and develop novel therapeutic approaches for unmet medical needs.a