Effects of Cys Mutation on Taurocholic Acid Transport by Mouse Ileal and Hepatic Sodium-dependent Bile Acid Transporters

Abstract

  All cysteines of mouse ileal and hepatic sodium-dependent bile acid transporters (Isbt and Ntcp, respectively) were individually replaced by alanine. Replacement of Cys¹⁰⁶ in Isbt and Cys⁹⁶ in Ntcp, which are located closely in alignment, decreased taurocholate uptake. Although Cys⁵¹ in Isbt is conserved in Ntcp, the replacement spoiled Isbt only. Both similarity and difference in the arrangement of functional sites are suggested.