Substrate specificity of MATE1 and MATE2-K, human multidrug and toxin extrusions/H+-organic cation antiporters
Substrate specificity of MATE1 and MATE2-K, human multidrug and toxin extrusions/H+-organic cation antiporters
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DOI：
10.1016/j.bcp.2007.04.010
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发表时间：
2007-07-15
影响因子：
5.8
通讯作者：
Inui, Ken-ichi
中科院分区：
文献类型：
--
作者：
Tanihara, Yuko;Masuda, Satohiro;Inui, Ken-ichi
通过将hMATE 1和hMATE 2-K的cDNA转染HEK 293细胞，检查人（h）多药和毒素外排（MATE）1和hMATE 2-K的底物特异性，以发现这两种转运蛋白之间的功能差异。Western印迹显示，在还原条件下，转染子以及人肾刷状缘膜中hMATE 1和hMATE 2-K的特异性信号分别与50和40 kDa大小一致。在存在反向H+梯度的情况下，在hMATE 1-和hMATE 2-K-表达细胞中刺激了各种化合物（如四乙基铵、1-甲基-4-苯基吡啶、西咪替丁、二甲双胍、肌酐、胍、普鲁卡因胺和拓扑替康）的转运活性。除阳离子化合物外，阴离子硫酸雌酮、阿昔洛韦和更昔洛韦也被认为是这些转运蛋白的底物。动力学分析表明，hMATE 1介导的四乙基铵、1-甲基-4-苯基吡啶、西咪替丁、二甲双胍、胍、普鲁卡因胺、拓扑替康、硫酸雌酮、阿昔洛韦和更昔洛韦转运的米氏常数分别为（mM）0.38、0.10、0.17、0.78、2.10、1.23、0.07、0.47、2.64和5.12。hMATE 2-K的那些分别为0.76、0.11、0.12、1.98、4.20、1.58、0.06、0.85、4.32和4.28。尽管它们对hMATE 1和hMATE 2-K的亲和力相似，但两性离子头孢菌素和头孢拉定被发现是hMATE 1的特异性底物，而不是hMATE 2-K的特异性底物。左氧氟沙星和环丙沙星不被转运，但被证明是这些转运蛋白的有效抑制剂。这些结果表明，hMATE 1和hMATE 2-K作为解毒系统一起发挥作用，通过介导细胞内离子化合物穿过肾脏刷状缘膜的肾小管分泌。(C)2007爱思唯尔公司All rights reserved.
The substrate specificities of human (h) multidrug and toxin extrusion (MATE) 1 and hMATE2-K were examined to find functional differences between these two transporters by the transfection of the cDNA of hMATE1 and hMATE2-K into HEK293 cells. Western blotting revealed specific signals for hMATE1 and hMATE2-K consistent with a size of 50 and 40 kDa, respectively, in the transfectants as well as human renal brush-border membranes under reducing conditions. In the presence of oppositely directed H+-gradient, the transport activities of various compounds such as tetraethylammonium, 1-methyl-4-phenylpyridinium, cimetidine, metformin, creatinine, guanidine, procainamide, and topotecan were stimulated in hMATE1- and hMATE2 -K- expressing cells. In addition to cationic compounds, anionic estrone sulfate, acyclovir, and ganciclovir were also recognized as substrates of these transporters. Kinetic analyses demonstrated the Michaelis-Menten constants for the hMATE1-mediated transport of tetraethylammonium, 1-methyl-4-phenylpyridinium, cimetidine, metformin, guanidine, procainamide, topotecan, estrone sulfate, acycrovir, and ganciclovir to be (in mM) 0.38,0.10,0.17,0.78, 2.10, 1.23,0.07, 0.47, 2.64, and 5.12, respectively. Those for hMATE2-K were 0.76, 0.11, 0.12, 1.98, 4.20, 1.58, 0.06, 0.85, 4.32, and 4.28, respectively. Although their affinity for hMATE1 and hMATE2-K was similar, the zwitterionic cephalexin and cephradine were revealed to be specific substrates of hMATE1, but not of hMATE2-K. Levofloxacin and ciprofloxacin were not transported, but were demonstrated to be potent inhibitors of these transporters. These results suggest that hMATE1 and hMATE2-K function together as a detoxication system, by mediating the tubular secretion of intracellular ionic compounds across the brush-border membranes of the kidney. (C) 2007 Elsevier Inc. All rights reserved.