The Ileocyte Basolateral Organic Solute Transporter (OSTα–OSTβ) Complex: Finding The Missing Link in Enterohepatic Circulation

Abstract

Many drugs are removed from the body through a multistep process that includes covalent conjugation, transport into the bile, and excretion. Bile acids are transported across the ileocyte apical (brush border) membrane by the apical sodium-dependent bile-acid transporter (Asbt), but the identity of the primary transporter responsible for moving bile acids across the basolateral membrane of the ileocyte has remained a mystery, although not for a lack of protein pretenders to the throne. Recent insights from transcriptional profiling studies of wild-type and Asbt-deficient mice indicate that a complex formed by the organic solute carrier proteins α and β (Ostα and Ostβ) is the primary transporter for basolateral bile acid transport.