MRP2, a human conjugate export pump, is present and transports fluo 3 into apical vacuoles of Hep G2 cells
MRP2, a human conjugate export pump, is present and transports fluo 3 into apical vacuoles of Hep G2 cells
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DOI：
10.1152/ajpgi.2000.278.4.g522
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发表时间：
2000-04-01
影响因子：
4.5
通讯作者：
Keppler, D
中科院分区：
文献类型：
--
作者：
Cantz, T;Nies, AT;Keppler, D
多药耐药蛋白2（MRP2，符号ABCC2）将阴离子缀合物和某些两亲性阴离子转运穿过极化细胞的顶膜，人肝癌Hep G2细胞保留肝极性并形成顶端液泡，其中分泌亲胆物质。免疫荧光显微镜显示，人MRP2在极化Hep G2细胞的顶液泡膜中表达，而异构体MRP3定位于侧膜，免疫印迹和逆转录PCR证实了MRP2和MRP3的表达。 Flue 3分泌到顶端液泡中被环孢菌素A抑制，但不被多药耐药1 P-糖蛋白的选择性抑制剂抑制。此外，羧基荧光素、罗丹明123和荧光胆汁盐衍生物熊去氧胆基-(Nε-硝基苯并恶二唑基)-赖氨酸和胆酰氨基荧光素被分泌到顶端液泡中；后两者可能通过胆盐输出泵。我们得出的结论是，MRP2介导flue 3分泌到极化的Hep G2细胞的顶端液泡中。因此，可以通过荧光阴离子（例如fluo 3）的分泌来分析人MRP2的功能和抑制剂的作用。
The multidrug resistance protein 2 (MRP2, symbol ABCC2) transports anionic conjugates and certain amphiphilic anions across the apical membrane of polarized cells, Human hepatoma Hep G2 cells retain hepatic polarity and form apical vacuoles into which cholephilic substances are secreted. Immunofluorescence microscopy showed that human MRP2 was expressed in the apical vacuole membrane of polarized Hep G2 cells, whereas the isoform MRP3 was localized to the lateral membrane, Expression of both MRP2 and MRP3 was confirmed by immunoblotting and reverse transcription PCR. Flue 3 secretion into the apical vacuoles was inhibited by cyclosporin A but not by selective inhibitors of multidrug resistance 1 P-glycoprotein. In addition, carboxyfluorescein, rhodamine 123, and the fluorescent bile salt derivatives ursodeoxycholyl-(N epsilon-nitrobenzoxadiazolyl)-lysine and cholylglycylamido-fluorescein were secreted into the apical vacuoles; the latter two probably via the bile salt export pump. We conclude that MRP2 mediates flue 3 secretion into the apical vacuoles of polarized Hep G2 cells. Thus the function of human MRP2 and the action of inhibitors can be analyzed by the secretion of fluorescent anions such as fluo 3.