Organic solute transporter subunit alpha

Essential component of the Ost-alpha/Ost-beta complex, a heterodimer that acts as the intestinal basolateral transporter responsible for bile acid export from enterocytes into portal blood. Efficiently transports the major species of bile acids (taurocholate). Taurine conjugates are transported more efficiently across the basolateral membrane than glycine-conjugated bile acids (By similarity). Can also transport steroids such as estrone 3-sulfate and dehydroepiandrosterone 3-sulfate, therefore playing a role in the enterohepatic circulation of sterols. Able to transport eicosanoids such as prostaglandin E2 (By similarity).