Rapid modulation of the organic anion transporting polypeptide 2B1 (OATP2B1, SLCO2B1) function by protein kinase C-mediated internalization

摘要: Members of the organic anion transporting polypeptide (OATP) family are involved in various pharmacological, pathophysiological, and physiological processes, such as hepatic drug uptake, progress cancer, or transport hormones. Although variability expression function OATPs has been investigated detail, data concerning regulation rather limited. Here, we report a novel mechanism for rapid OATP2B1 mediated by protein kinase C (PKC) resulting significant changes activity. PKC activation phorbol ester (phorbol 12-myristate 13-acetate, PMA) resulted increased phosphorylation well reduced activity with decrease Vmax E1S uptake (288 ± 21 (control) versus 165 16 pmol/min/mg (PMA)). This effect was sensitive to inhibitor bisindolylmaleimide I (BIM-I). Confocal microscopy, fluorescence-based internalization assay, live-cell imaging using green fluorescent protein-tagged revealed that inhibition due transporter. Furthermore, colocalization LAMP-2 chloroquine-sensitive degradation suggest internalized is targeted lysosomal pathway. With regard underlying caveolin/lipid raft-mediated endocytosis failed prevent internalization, whereas clathrin-mediated processes blocked sequestration. However, small interfering RNA-mediated clathrin knock-down affected general trafficking intracellular accumulation absence PMA. In conclusion, our demonstrate regulated PKC-mediated, clathrin-dependent followed degradation. could be shown an ex vivo placenta perfusion. Our findings represent new, human OATPs.