This gene encodes a member of the organic anion transporter family. The encoded protein is a transmembrane receptor that mediates the sodium-independent uptake of thyroid hormones in brain tissues. This protein has particularly high affinity for the thyroid hormones thyroxine, tri-iodothyronine and reverse tri-iodothyronine. Polymorphisms in the gene encoding this protein may be associated with fatigue and depression in patients suffering from hyperthyroidism. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2009].