Putative organic anion antiporter with apparent broad substrate specificity. Recognizes various substrates including thyroid hormone L-thyroxine, prostanoids such as prostaglandin E1 and E2, bile acids such as taurocholate, glycolate and glycochenodeoxycholate and peptide hormones such as L-arginine vasopressin, likely operating in a tissue-specific manner (  ). The transport mechanism, its electrogenicity and potential tissue-specific counterions remain to be elucidated (Probable).
Subcellular locations: Basolateral cell membrane
Localized to the basolateral membrane of choroid plexus epithelium.
Subcellular locations: Apical cell membrane, Basal cell membrane
Localized to the basal membrane of Sertoli cells . Localized to the apical membrane of choroid plexus epithelium .
Generally the expression of isoform 1 is higher than that of isoform 2.
Expressed in placental trophoblasts (, ). Expressed in pancreas, kidney, liver, lung, brain, heart, cerebellum, peripheral blood leukocyte, colon, small intestine, ovary, testis, prostate, thyroid, thymus and spleen ( ). Expressed in fetal brain, heart, kidney, liver, lung, skeletal muscle, spleen and pancreas . In testis, detected in spermatogonia at different stages and absent from Sertoli cells. Expressed in the choroid plexus epithelium, at the basolateral membrane. In brain, also very abundant in the gray matter of the frontal cortex, but not associated with neuronal cell bodies. Not detected in the white matter .
Expressed in heart, brain, cerebellum, testis, lung, thyroid, spoleen and liver . In testis, primarily localized to the basal membrane of Sertoli cells and weakly expressed within the tubules (, ). In testis, also present in spermatogonia at different stages. In brain, expressed in the choroid plexus epithelium, at the apical membrane as well as in the subapical intracellular vesicular compartments. In brain, also associated with neuronal bodies and axons in both the gray and the white matters of the frontal cortex .