Novel membrane transporter OCTN1 mediates multispecific, bidirectional, and pH-dependent transport of organic cations.

摘要: In the present study, functional characteristics of organic cation transporter (OCTN)1, which was cloned as pH-dependent tetraethylammonium (TEA) when expressed in mammalian human embryonic kidney (HEK)293 cells, were further investigated using Xenopus oocytes well HEK293 cells gene expression systems. When OCTN1-derived complementary RNA injected into oocytes, transport [14C]TEA observed same cells. contrast, a replacement sodium ions with potassium surrounding medium did not cause any change uptake OCTN1. addition, OCTN1 efflux TEA from pH dependent, an accelerated rate at acidic external pH. Accordingly, membrane potential or are suggested to have no influence on and activity is directly affected by itself. Furthermore, addition unlabeled enhanced preloaded [14C]TEA. These observations suggest that bidirectional transporter. OCTN1-mediated inhibited various cations such cimetidine, procainamide, pyrilamine, quinidine, quinine, verapamil. uptakes cationic compounds [3H]pyrilamine, [3H]quinidine, [3H]verapamil zwitterionic L-[3H]carnitine increased oocytes. functionally demonstrated be multispecific transporter, presumably functions proton/organic antiporter renal apical other tissues.