Direct Comparison of Manganese Detoxification/Efflux Proteins and Molecular Characterization of ZnT10 Protein as a Manganese Transporter
Direct Comparison of Manganese Detoxification/Efflux Proteins and Molecular Characterization of ZnT10 Protein as a Manganese Transporter
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DOI：
10.1074/jbc.m116.728014
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发表时间：
2016-07-08
影响因子：
4.8
通讯作者：
Kambe, Taiho
中科院分区：
文献类型：
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作者：
Nishito, Yukina;Tsuji, Natsuko;Kambe, Taiho
锰的稳态包括参与锰流入和流出的特定蛋白质的协调调节。然而，参与解毒/外排的蛋白质尚未完全解决，也没有选择其金属底物的基础。在这里，我们比较了六种蛋白质，据报道，这是参与锰解毒/流出，通过评估他们的能力，以减少锰毒性在鸡DT 40细胞，发现人ZnT 10（hZnT 10）是最显着的贡献者。hZnT 10和锌特异性转运蛋白hZnT 1之间的结构域交换和取代分析表明，残基Asn（43）是赋予hZnT 10独特的锰动员活性所必需的，该残基对应于构成其他ZnT转运蛋白中潜在的膜内锌配位位点的His残基;跨膜结构域II和V中的残基Cys（52）和Leu（242）在控制hZnT 10的金属特异性中起微妙的作用。有趣的是，His Asn回复突变体在hZnT 1赋予锰转运活性和锌转运活性的损失。这些结果提供了有关脊椎动物细胞中锰解毒/外排机制以及hZnT 10作为锰转运蛋白的分子特征的重要信息。
Manganese homeostasis involves coordinated regulation of specific proteins involved in manganese influx and efflux. However, the proteins that are involved in detoxification/efflux have not been completely resolved nor has the basis by which they select their metal substrate. Here, we compared six proteins, which were reported to be involved in manganese detoxification/efflux, by evaluating their ability to reduce manganese toxicity in chicken DT40 cells, finding that human ZnT10 (hZnT10) was the most significant contributor. A domain swapping and substitution analysis between hZnT10 and the zinc-specific transporter hZnT1 showed that residue Asn(43), which corresponds to the His residue constituting the potential intramembranous zinc coordination site in other ZnT transporters, is necessary to impart hZnT10's unique manganese mobilization activity; residues Cys(52) and Leu(242) in transmembrane domains II and V play a subtler role in controlling the metal specificity of hZnT10. Interestingly, the His Asn reversion mutant in hZnT1 conferred manganese transport activity and loss of zinc transport activity. These results provide important information about manganese detoxification/efflux mechanisms in vertebrate cells as well as the molecular characterization of hZnT10 as a manganese transporter.