Multispecific organic anion transporter MOAT

Figure 28.3. Transport of bile acids and other constituents across the hepatocyte. The Na+ dependent bile salt (taurocholate) transporter (BA-) is shown on the sinusoidal membrane that utihzes the Na+ gradient maintained by the NAK pump, shown here on the lateral aspect of the plasmalemma. Bile salt transcellular transport involves microtubules, which then dehver substrate to the canahcular bile salt transporter (1). Bilary excretion of GSH, gluc-uronate (GluA), and sulfate conjugates of compounds such as 17P-estradiol (E2), bilirubin, and bromosulfothalein (BSP) is catalyzed by the multispecific organic anion transporter (MOAT 2). Both 1 and 2 are members of the ABC family of ATP-dependent transporters that also includes P-glycoprotein (3), another canalicular transporter catalyzing excretion of hpophihc compounds such as the chemotherapeutic drug, daunorubicin.

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