Na(+)/monocarboxylate cotransporter SMCT2 and related proteins; solute-binding domain
SMCT2 is a low-affinity transporter for short-chain fatty acids, lactate, pyruvate, and nicotinate. Human SMCT2 (hSMCT2) is encoded by the SLC5A12 gene. SMCT2 is expressed in the kidney, small intestine, skeletal muscle, and retina. In the kidney, it is expressed in the apical membrane of the proximal convoluted tubule, along the entire length of the tubule (in contrast to the high-affinity monocarboxylate transporter SMCT1, belonging to a different family, which is limited to the S3 segment of the tubule). SMCT2 may initiate lactate absorption in the early parts of the tubule. In the retina, SMCT1 and SMCT2 may play a differential role in monocarboxylate transport in a cell type-specific manner, SMCT2 is expressed exclusively in Muller cells. Nicotine transport by hSMCT2 is inhibited by several non-steroidal anti-inflammatory drugs. This subgroup belongs to the solute carrier 5 (SLC5) transporter family.
Jiyao W et al.(2023). "The conserved domain database in 2023.",