SLC10A1(SOLUTE CARRIER FAMILY 10 (SODIUM/BILE ACID COTRANSPORTER FAMILY), MEMBER 1),also called NTCP or NTCP1,is found in the basolateral membranes of hepatocytes, which is also involved in the reabsorption of bile acids. The SLC10A1 gene is mapped on 14q24.2.The SLC10A1 gene contains 5 exons and spans about 23 kb. Like other sodium/bile acid transporters, SLC10A1 contains an exoplasmic N terminus, an odd number of transmembrane regions, and a cytoplasmic C terminus. Two amphipathic sequences are critical for intramolecular interactions and for proper trafficking of SLC10A1 to the plasma membrane.Injection of in vitro transcribed NTCP cRNA into Xenopus oocytes resulted in the expression of Na(+)-dependent taurocholate uptake. NTCP-mediated taurocholate uptake in oocytes was inhibited by all major bile acid derivatives and by bromosulfophthalein.