Sodium-dependent multivitamin transporter that mediates the electrogenic transport of pantothenate, biotin, lipoate and iodide (     ). Functions as a Na(+)-coupled substrate symporter where the stoichiometry of Na(+):substrate is 2:1, creating an electrochemical Na(+) gradient used as driving force for substrate uptake (, ). Required for biotin and pantothenate uptake in the intestine across the brush border membrane . Plays a role in the maintenance of intestinal mucosa integrity, by providing the gut mucosa with biotin (By similarity). Contributes to the luminal uptake of biotin and pantothenate into the brain across the blood-brain barrier .
Subcellular locations: Cell membrane, Apical cell membrane
Preferentially localized at the luminal membrane of brain capillary endothelium . Localized to the brush border/apical membrane of intestine and renal polarized cells .
Subcellular locations: Cell membrane
(Microbial infection) Exposure to E.coli lipopolysaccharides leads to reduced cell membrane localization.
Expressed in microvessels of the brain (at protein level) . Expressed in heart, brain, placenta, lung, liver, skeletal muscle, kidney, and pancreas .