Abstract :
The rat organic anion transport protein (oatp) is present mainly in the apical membrane of the proximal tubule of the renal outer medulla and in the basolateral plasma membrane in the liver. The differential basolateral and apical subcellular distribution of oatp is due to differential biosynthetic processing and transport. Reduction of the protein in the kidney produces a 33 and a 37 kDa peptide, but has no effect on the protein in the liver. The liver protein is abundant in Na2CO3-extracted membranes and sinusoidal plasma membrane preparations.