Functional characterization of testis-specific rodent multidrug and toxic compound extrusion 2, a class III MATE-type polyspecific H+/organic cation exporter
Functional characterization of testis-specific rodent multidrug and toxic compound extrusion 2, a class III MATE-type polyspecific H+/organic cation exporter
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DOI：
10.1152/ajpcell.00280.2007
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发表时间：
2007-11-01
影响因子：
5.5
通讯作者：
Moriyama, Yoshinori
中科院分区：
文献类型：
--
作者：
Hiasa, Miki;Matsumoto, Takuya;Moriyama, Yoshinori
哺乳动物多药和毒性化合物挤出（MATE）蛋白分为三个亚家族：I类、II类和III类。我们先前表明，这些家族中的两个在肝脏和肾脏中的最终排泄步骤中充当有机阳离子（OC）的多特异性H+偶联转运蛋白（Otsuka等人，Proc Natl Acad Sci USA 102：17923-17928，2005; Omote等人，Trends Pharmacol Sci 27：587-593，2006）。啮齿动物MATE 2蛋白是III类MATE转运蛋白，其分子性质以及转运特性仍有待表征。在本研究中，我们研究了小鼠MATE 2（mMATE 2）的转运特性和定位。在人胚肾（HEK）-293细胞中表达时，mMATE 2定位于细胞内细胞器和质膜。mMATE 2介导pH依赖性TEA转运，其底物特异性与mMATE 1相似，但不同，mMATE 1偏好N-甲基烟酰胺和胍作为底物。将在昆虫细胞中表达的mMATE 2溶解并用细菌H+-ATP酶重构到脂质体中。所得到的蛋白脂质体表现出ATP依赖性的TEA的摄取是敏感的羰基氰3-氯苯腙，但不受缬氨霉素在K+的存在下。使用特异性抗体的免疫学技术显示，mMATE 2在睾丸间质细胞中特异性表达。因此，mMATE 2似乎在Leydig细胞中充当多特异性H+/OC输出者。可以得出结论，所有类别的哺乳动物MATE蛋白作为多特异性和电中性转运的有机阳离子。
Mammalian multidrug and toxic compound extrusion ( MATE) proteins are classified into three subfamilies: classes I, II, and III. We previously showed that two of these families act as polyspecific H+-coupled transporters of organic cations (OCs) at final excretion steps in liver and kidney ( Otsuka et al. Proc Natl Acad Sci USA 102: 17923-17928, 2005; Omote et al. Trends Pharmacol Sci 27: 587-593, 2006). Rodent MATE2 proteins are class III MATE transporters, the molecular nature, as well as transport properties, of which remain to be characterized. In the present study, we investigated the transport properties and localization of mouse MATE2 (mMATE2). On expression in human embryonic kidney (HEK)-293 cells, mMATE2 localized to the intracellular organelles and plasma membrane. mMATE2 mediated pH-dependent TEA transport with substrate specificity similar to, but distinct from, that of mMATE1, which prefers N-methylnicotinamide and guanidine as substrates. mMATE2 expressed in insect cells was solubilized and reconstituted with bacterial H+-ATPase into liposomes. The resultant proteoliposomes exhibited ATP-dependent uptake of TEA that was sensitive to carbonyl cyanide 3-chlorophenylhydrazone but unaffected by valinomycin in the presence of K+. Immunologic techniques using specific antibodies revealed that mMATE2 was specifically expressed in testicular Leydig cells. Thus mMATE2 appears to act as a polyspecific H+/OC exporter in Leydig cells. It is concluded that all classes of mammalian MATE proteins act as polyspecific and electroneutral transporters of organic cations.