MONOCARBOXYLIC ACID TRANSPORTERS

Monocarboxylate transporters (or MCTs) are widely distributed in the body and responsible for the uptake of short-chain monocarboxylates, hormones, nutrients, amino acids, as well as xenobiotics. In total, there are 14 isoforms of the MCT family (MCTs 1-14, SLC16A1-14), with MCTs 1-4 extensively characterized as proton-dependent transporters with a critical role in the transport of products of the glycolysis cycle (i.e., lactate and pyruvate), as well as ketone bodies, across plasma membranes. The other MCTs 5-14 have not been extensively evaluated; however, their substrate specificities have more recently begun to be characterized. Monocarboxylate substrates are also transported by two members of the SLC5A family in a sodium-dependent manner, namely, SMCT1 (SLC5A8) and SMCT2 (SLC5A12) . This review will provide a summary of the current literature focusing on the characterization, function, and regulation of the monocarboxylate transporters, and on their roles in drug disposition and in health and disease.