Sodium-dependent multivitamin transporter (SLC5A6)

Sodium-dependent multivitamin transporter (SLC5A6, commonly abbreviated SMVT) is a membrane protein that belongs to the solute carrier SLC5 family and functions as a sodium:solute symporter. It is essential for the cellular uptake of water-soluble vitamins including biotin (B7), pantothenic acid (B5), and the vitamin-like molecule α-lipoic acid, as well as iodide. SMVT operates by coupling vitamin transport with sodium ions using a 2:1 stoichiometry. The protein is broadly expressed in human tissues such as intestine, placenta, brain, liver, kidney, and heart, playing a crucial role in maintaining systemic vitamin homeostasis. Genetic deficiencies in SLC5A6 are associated with multisystemic metabolic disorders and constitute a rare cause of inherited biotin deficiency and related neuropathies. Owing to its high capacity and substrate specificity, SMVT is also a target for drug delivery, particularly for prodrugs or conjugates resembling its endogenous substrates. Saturation or competition among transported molecules can pose risks for deficiency. There are currently no approved direct inhibitors or agonists in clinical use, but the transporter remains of research interest in pharmacology and metabolic disease.

Other names

SMVTNa(+)-dependent multivitamin transporterhSMVTSodium-dependent multivitamin transporterSolute carrier family 5 member 6COMNBNERIBSMVTDsolute carrier family 5 (sodium/multivitamin and iodide cotransporter), member 6solute carrier family 5 (sodium-dependent vitamin transporter), member 6

Na(+)-coupled substrate symport: Uses the sodium gradient across cell membranes to co-transport vitamins and biotinylated/drug molecules into cells. Drug delivery: Some therapeutic strategies attempt to exploit SMVT for enhanced intestinal or tissue uptake of drugs that are chemically modified to act as substrates.