SLC5A6
Domain
The C-terminal tail is important for biotin uptake as well as apical localization in polarized cells.
Function
Sodium-dependent multivitamin transporter that mediates the electrogenic transport of pantothenate, biotin, lipoate and iodide (PubMed:10329687, PubMed:15561972, PubMed:19211916, PubMed:20980265, PubMed:21570947, PubMed:22015582, PubMed:25809983, PubMed:25971966, PubMed:27904971, PubMed:28052864, PubMed:31754459). 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 (PubMed:10329687, PubMed:20980265). Required for biotin and pantothenate uptake in the intestine across the brush border membrane (PubMed:19211916). 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 (PubMed:25809983).
Involvement in disease
Sodium-dependent multivitamin transporter deficiency
SMVTD
An autosomal recessive multisystemic metabolic disorder characterized by early infantile onset, progressive neurodegeneration, global developmental delay, and developmental regression with loss of early motor and cognitive milestones. Additional variable features include seizures, ataxia, spasticity, peripheral neuropathy, immune defects, and osteopenia. Treatment with biotin, pantothenic acid, and lipoate may result in clinical improvement.
None
The disease is caused by variants affecting the gene represented in this entry.
Peripheral motor neuropathy, childhood-onset, biotin-responsive
COMNB
An autosomal recessive disorder characterized by distal muscle weakness and atrophy appearing late in the first decade of life. The disorder predominantly affects the upper limbs and hands, resulting in difficulties with fine motor skills. Some patients may have lower limb involvement, resulting in gait difficulties. Additional features may include spasticity, ataxia, and cerebellar signs. Sensation is intact, and patients have normal cognitive development. Treatment with biotin, pantothenic acid, and lipoic acid may result in clinical improvement.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
May be glycosylated.
Sequence Similarities
Belongs to the sodium:solute symporter (SSF) (TC 2.A.21) family.
Tissue Specificity
Expressed in microvessels of the brain (at protein level) (PubMed:25809983). Expressed in heart, brain, placenta, lung, liver, skeletal muscle, kidney, and pancreas (PubMed:10329687).
Cellular localization
- Cell membrane
- Multi-pass membrane protein
- Apical cell membrane
- Multi-pass membrane protein
- Preferentially localized at the luminal membrane of brain capillary endothelium (PubMed:25809983). Localized to the brush border/apical membrane of intestine and renal polarized cells (PubMed:19211916).
- Cell membrane
- Multi-pass membrane protein
- (Microbial infection) Exposure to E.coli lipopolysaccharides leads to reduced cell membrane localization.
Alternative names
SMVT, SLC5A6, Sodium-dependent multivitamin transporter, Na(+)-dependent multivitamin transporter, hSMVT, Solute carrier family 5 member 6