A molecule of glycocholate, taurocholate, or taurochenodeoxycholate is transported from the cytosol to the extracellular space, coupled to the hydrolysis of a molecule of cytosolic ATP to ADP and orthophosphate. This reaction is mediated by ABCB3 (MRP3). In the body, this reaction mediates the release of bile salts from enterocytes into the blood (Kullak-Ublick et al. 2004; Trauner and Boyer 2002). In the cytosol, bile salts and acids are bound to a carrier protein, FABP6 (I-BABP) (Fujita et al. 1995), and in the blood these molecules are complexed with albumin. The mechanisms by which transport across the plasma membrane is coupled to release FABP6 and binding to albumin are unknown, so the entire process is annotated as a single concerted event.