Molecular identification and characterization of novel members of the human organic anion transporter (OATP) family

We identified three novel transporters structurally belonging to the organi c anion transporting polypeptide (OATP) family in humans. Since previously known rat oatp1 to 3 do not necessarily correspond to the human OATPs in te rms of either tissue distribution or function, here we designate the newly identified human OATPs as OATP-B, -D and -E, and we rename the previously k nown human OATP as OATP-A. OATP-C proved to be identical with the recently reported LST1/OATP-2, Expression profiles of the five OATPs and the prostag landin transporter PGT (a member of OATP family) in human tissues showed th at OATP-C is exclusively localized in liver, OATP-A and PGT are expressed i n restricted ranges of tissues, and OATP-B, -D and -E show broad expression profiles. OATP-B, -C, -D and -E exhibited transport activity for [H-3]estr one-3-sulfate as a common substrate. OATP-C has a high transport activity w ith broad substrate specificity. (C) 2000 Academic Press.