Transporter for bile acids. Highly expressed in brain and small intestine, and moderately expressed in colon, heart, prostate, and testis. Very low levels were detected in kidney, liver, ovary, placenta, spleen, and thymus. Activated following N-terminal proteolytic cleavage by thrombin and/or proteases. Belongs to the bile acid:sodium symporter (BASS) (TC 2.A.28) family.