The SLC16A family of monocarboxylate transporters (MCTs) is composed of 14 members. MCTs play a central role in cellular metabolism and metabolic communication between tissues. The rapid transport of monocarboxylates such as pyruvate, lactate, and ketone bodies (acetoacetate and β-hydroxybutyrate) across the plasma membrane of cells is facilitated by proton-linked MCTs. MCTs share similarities in sequence and protein structure, but each member differs from others in the substrates that they transport. For example, lactate among other monocarboxylates, is the primary substrate for MCT1, MCT2, MCT3 and MCT42. All family members are predicted to have 12 transmembrane helices (TMs) with intracellular C- and N-termini as well as a large cytosolic loop
