CHIMERIC DOPAMINE NOREPINEPHRINE TRANSPORTERS DELINEATE STRUCTURAL DOMAINS INFLUENCING SELECTIVITY FOR CATECHOLAMINES AND 1-METHYL-4-PHENYLPYRIDINIUM
CHIMERIC DOPAMINE NOREPINEPHRINE TRANSPORTERS DELINEATE STRUCTURAL DOMAINS INFLUENCING SELECTIVITY FOR CATECHOLAMINES AND 1-METHYL-4-PHENYLPYRIDINIUM
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DOI：
10.1073/pnas.91.26.12584
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发表时间：
1994-12-20
影响因子：
11.1
通讯作者：
AMARA, SG
中科院分区：
文献类型：
--
作者：
BUCK, KJ;AMARA, SG
多巴胺（DA）和去甲肾上腺素（NE）转运体对儿茶酚胺和诱导帕金森病的神经毒素1-甲基-4-苯基吡啶（MPP(+)）的选择性表现出重要差异，但它们的初级序列和预测拓扑结构却惊人地相似。为了描述导致DA和NE转运体之间药理学和动力学差异的离散结构域，通过限制性内切位点不依赖的方法生成了一系列重组嵌合体，并在哺乳动物细胞中表达。嵌合体的功能分析描绘了跨越第一到第三跨膜结构域（TM1-3）和TM10-11的两个离散区域，这导致了它们对DA、NE和MPP（+）的表观亲和力的差异。这些研究还表明，与NE相比，DA转运体的TM2-3在选择性地增加DA摄取速率方面起作用。DA转运体的TM4-8可能影响MPP（+）被细胞吸收的相对速率，并可能导致其对表达DA转运体的神经元的选择性毒性。这些结构-功能研究使用Na+-和Cl-依赖转运体超家族成员的嵌合体，为确定DA和NE转运体对底物识别和转运的特定结构或调节决定因素提供了一个框架。
The dopamine (DA) and norephinephrine (NE) transporters demonstrate important differences in their selectivity for catecholamines and the parkinsonism-inducing neurotoxin 1-methyl-4-phenylpyridinium (MPP(+)), yet their primary sequences and predicted topology are strikingly similar. To delineate discrete structural domains contributing to pharmacologic and kinetic differences between the DA and NE transporters, a series of recombinant chimeras was generated by a restriction site-independent method and expressed in mammalian cells. Functional analyses of the chimeras delineate two discrete regions spanning the first through the third transmembrane domains (TM1-3) and TM10-11 that contribute to differences in their apparent affinities for DA, NE, and MPP(+). These studies also suggest that TM2-3 of the DA transporter have a role in selectively increasing the rate of DA uptake as compared with NE. TM4-8 of the DA transporter may influence the relative rate with which MPP(+) is taken up into cells and could contribute to its selective toxicity in neurons expressing the DA transporter. These structure-function studies using chimeras of members of the superfamily of Na+- and Cl--dependent transporters provide a framework for identifying the specific structural or regulatory determinants contributing to substrate recognition and translocation by the DA and NE transporters.