Sodium-coupled monocarboxylate transporter 2 (SLC5A12)

Sodium-coupled monocarboxylate transporter 2 (SLC5A12, SMCT2) is a member of the solute carrier family 5, structurally composed of 13 transmembrane domains with cytoplasmic and exoplasmic termini. As an electroneutral, low-affinity sodium-dependent transporter localized to the apical membrane of epithelial cells in kidney and intestines, and selectively expressed in astrocytes and Müller cells of the brain and retina, SLC5A12 plays a principal role in the bulk reabsorption and transport of monocarboxylates such as lactate, pyruvate, propionate, and nicotinate from extracellular compartments into cells. Its low substrate affinity relative to SLC5A8 facilitates high-capacity transport in tissues with abundant dietary or endogenous monocarboxylates. SLC5A12 is physiologically critical for energy substrate handling, acid-base balance, and possibly immune cell function. No drugs or inhibitors currently target SLC5A12 clinically, and its direct pathological roles remain underexplored compared to other family members.

Other names

SLC5A12SMCT2Electroneutral sodium monocarboxylate cotransporterSodium-iodide related cotransporterLow-affinity sodium-lactate cotransporterSolute carrier family 5 member 12Sodium-coupled monocarboxylate transporter 2MGC52019

Not established for SLC5A12, as no drugs currently known to act directly on it. In principle, inhibitors would block sodium-coupled transport of monocarboxylates, reducing their cellular reabsorption and uptake.