SLC16A2
Function
Specific thyroid hormone transmembrane transporter, that mediates both uptake and efflux of thyroid hormones across the cell membrane independently of pH or a Na(+) gradient. Major substrates are the iodothyronines T3 and T4 and to a lesser extent rT3 and 3,3-diiodothyronine (3,3'-T2) (PubMed:16887882, PubMed:18337592, PubMed:20628049, PubMed:23550058, PubMed:26426690, PubMed:27805744, PubMed:31436139). Acts as an important mediator of thyroid hormone transport, especially T3, through the blood-brain barrier (Probable) (PubMed:28526555).
Involvement in disease
Monocarboxylate transporter 8 deficiency
MCT8 deficiency
Consists of a severe form of X-linked psychomotor retardation combined with abnormal thyroid hormone (TH) levels. Thyroid hormone deficiency can be caused by defects of hormone synthesis and action, but it has also been linked to a defect in cellular hormone transport. Affected patients are males with abnormal relative concentrations of three circulating iodothyronines, as well as severe neurological abnormalities, including global developmental delay, central hypotonia, spastic quadriplegia, dystonic movements, rotary nystagmus, and impaired gaze and hearing. Heterozygous females had a milder thyroid phenotype and no neurological defects.
None
The disease is caused by variants affecting the gene represented in this entry.
Sequence Similarities
Belongs to the major facilitator superfamily. Monocarboxylate porter (TC 2.A.1.13) family.
Tissue Specificity
Highly expressed in liver and heart (PubMed:7981683). In adult brain tissue expression is largely confined to endothelial cells of the blood-brain barrier (at protein level) (PubMed:18687783, PubMed:32143555).
Cellular localization
- Cell membrane
- Multi-pass membrane protein
- Apical cell membrane
- Multi-pass membrane protein
Alternative names
MCT7, MCT8, XPCT, SLC16A2, Monocarboxylate transporter 8, MCT 8, Monocarboxylate transporter 7, Solute carrier family 16 member 2, X-linked PEST-containing transporter, MCT 7