Identification of a sodium-dependent organic anion transporter from rat adrenal gland

• Published in: Biochemical and biophysical research communications 2004-04, Vol.316 (2), p.300-306
• Main Authors: Geyer, Joachim, Godoy, José R., Petzinger, Ernst
• Format: Article
• Language: English
• Subjects: Adrenal gland; Adrenal Glands - chemistry; Amino Acid Sequence; Animals; Biological Transport; Cloning, Molecular; Dehydroepiandrosterone sulfate; Dehydroepiandrosterone Sulfate - metabolism; DHEAS; Estrone - analogs & derivatives; Estrone - metabolism; Estrone-3-sulfate; Gene Components; Molecular Sequence Data; Oocytes - metabolism; Organic Anion Transporters - chemistry; Organic Anion Transporters - genetics; Organic Anion Transporters - metabolism; Organic Anion Transporters, Sodium-Dependent - chemistry; Organic Anion Transporters, Sodium-Dependent - genetics; Organic Anion Transporters, Sodium-Dependent - metabolism; Ouabain; Protein Structure, Tertiary; Rats; Sequence Alignment; SLC10; Soat; Sodium-dependent bile acid transporter; Sodium-dependent organic anion transporter; Taurocholate; Tissue Distribution; Xenopus laevis
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2004.02.048

In this study, a novel sodium-dependent organic anion transporter (Soat) was identified. Soat is expressed in rat brain, heart, kidney, lung, muscle, spleen, testis, adrenal gland, small intestine, and colon. The Soat protein consists of 370 amino acids and shows 42% and 31% overall amino acid sequence identity to the ileal sodium-dependent bile acid transporter (Isbt) and the Na +/taurocholate cotransporting polypeptide (Ntcp), respectively. Soat is predicted to have nine transmembrane domains, with an N-terminus outside the cell and an intracellular C-terminus. The Soat gene is localized on chromosome 14 and is coded by six exons mapped in region 14p22. When expressed in Xenopus laevis oocytes, Soat shows transport function for estrone-3-sulfate ( K m =31 μ M, V max=5557 fmol/oocyte/30 min) and dehydroepiandrosterone sulfate ( K m =30 μ M, V max=5682 fmol/oocyte/30 min). Soat does not transport taurocholate, estradiol-17β-glucuronide, nor ouabain.