Molecular cloning, functional characterization and tissue distribution of rat H+/organic cation antiporter MATE1
Molecular cloning, functional characterization and tissue distribution of rat H+/organic cation antiporter MATE1
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DOI：
10.1007/s11095-006-9016-3
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发表时间：
2006-08-01
影响因子：
3.7
通讯作者：
Inui, Ken-ichi
中科院分区：
文献类型：
--
作者：
Terada, Tomohiro;Masuda, Satohiro;Inui, Ken-ichi
目的.研究了大鼠H+/有机阳离子逆向转运蛋白MATE 1（multidrug and toxin extrusion 1）的转运特性和组织分布。通过聚合酶链反应（PCR）克隆大鼠MATE 1 cDNA。通过瞬时表达大鼠MATE 1的HEK 293细胞评估大鼠MATE 1的转运特征。采用北方杂交和实时荧光定量PCR检测大鼠MATE 1 mRNA的表达。MATE 1表达细胞对原型有机阳离子四乙基铵（TEA）的摄取具有浓度依赖性，在pH 8.4时显示最大值，在pH 6.0-6.5时最低。氯化铵诱导的细胞内酸化导致显著刺激TEA摄取。MATE 1不仅转运有机阳离子，如西咪替丁和二甲双胍，还转运两性离子化合物头孢氨苄。MATE 1 mRNA在肾脏和胎盘中大量表达，在脾脏中少量表达，但在肝脏中不表达。实时荧光定量PCR分析显示MATE 1主要表达于近曲小管和直小管。这些结果表明，MATE 1在肾近端小管中表达，并可使用反向H+梯度介导各种有机阳离子和头孢氨苄的转运。
Purpose. Transport characteristics and tissue distribution of the rat H+/organic cation antiporter MATE1 (multidrug and toxin extrusion 1) were examined.Methods. Rat MATE1 cDNA was isolated by polymerase chain reaction (PCR) cloning. Transport characteristics of rat MATE1 were assessed by HEK293 cells transiently expressing rat MATE1. The mRNA expression of rat MATE1 was examined by Northern blot and real-time PCR analyses.Results. The uptake of a prototypical organic cation tetraethylammonium (TEA) by MATE1-expressing cells was concentration-dependent, and showed the greatest value at pH 8.4 and the lowest at pH 6.0-6.5. Intracellular acidification induced by ammonium chloride resulted in a marked stimulation of TEA uptake. MATE1 transported not only organic cations such as cimetidine and metformin but also the zwitterionic compound cephalexin. MATE1 mRNA was expressed abundantly in the kidney and placenta, slightly in the spleen, but not expressed in the liver. Real-time PCR analysis of microdissected nephron segments showed that MATE1 was primarily expressed in the proximal convoluted and straight tubules.Conclusions. These findings indicate that MATE1 is expressed in the renal proximal tubules and can mediate the transport of various organic cations and cephalexin using an oppositely directed H+ gradient.