2.A.82.1.2
The organic solute transporter OSTα/OSTβ or SLC51A/SLC51B (transports the same anions as the 2.A.82.1.1 system) (The ileal enterocyte basolateral bile acid transporter; uses facilitated diffusion vian an anion:anion antiport mechanism with sulfate or bicarbonate as the counter anion) (Dawson et al., 2005).  Transports steroid-derived molecules as well as glycine and taurine conjugated bile acids (Ballatori et al. 2013).  Heterodimerization increases stability, facilitates post-translational modification and is required for delivery to the plasma membrane.  This system is essential for intestinal bile acid and dietary lipid absorption (Ballatori et al. 2013). Four OSTalpha amino acids (Ser228, Thr229, Gln269 and Glu305) affect expression of OSTalpha/beta and may influence OSTalpha/beta-mediated bile acid transport (Murphy et al. 2021).