Evaluation of 4′,6-Diamidino-2-phenylindole as a Fluorescent Probe Substrate for Rapid Assays of the Functionality of Human Multidrug and Toxin Extrusion Proteins

摘要: Multidrug and toxin extrusion protein 1 (MATE1) MATE2-K are organic cation/H+ antiporters that have recently been identified suggested to be responsible for the brush border secretory transport of many cationic drugs in renal tubules. We here report our finding 4′,6-diamidino-2-phenylindole (DAPI) can used as a probe substrate rapid assays functionality human MATEs, hMATE1, hMATE2-K, by taking advantage its fluorescent nature. The specific cellular uptakes DAPI cloned hMATE1 which were assessed fluorescence intensity, found saturable with Michaelis constants 1.13 3.16 μM, respectively, indicating is good both hMATEs. It was cations inhibit uptake extents inhibition correlation those [3H]cimetidine typical substrate, comparable performances substrates probes identifying inhibitors. Thus, an alternative enables fluorometric also other major cation transporters, transporter 2 (hOCT2), hOCT3, novel (hOCTN1), hOCTN2, cannot DAPI, although hOCT1, mainly expressed liver, can. Therefore, assay method hMATEs among transporters kidney.