Involvement of histidine-rich domain of ZIP family transporter TjZNT1 in metal ion specificity
Involvement of histidine-rich domain of ZIP family transporter TjZNT1 in metal ion specificity
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DOI：
10.1016/j.plaphy.2008.02.011
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发表时间：
2008-05-01
影响因子：
6.5
通讯作者：
Obata, Hitoshi
中科院分区：
文献类型：
--
作者：
Nishida, Sho;Mizuno, Takafumi;Obata, Hitoshi
Zrt/Irt 样蛋白 (ZIP) 家族通常通过调节阳离子转运到细胞质中来促进金属稳态。大多数 ZIP 成员在跨膜结构域 III 和 IV 之间有一个长的可变环，预计这些环位于细胞质中。这些环包含富含组氨酸的结构域（HRD），推测其可作为金属离子结合位点；然而，其作用尚未确定。我们之前确定 HRD 的删除不会影响 TjZNT1-a ZIP 转运蛋白的 Ni 耐受能力；对酵母的高镍耐受性。在本研究中，我们研究了 HRD 缺失对 TjZNT1 离子传输能力的影响。 HRD 的删除增加了对 Zn2+ 的特异性，但对 Cd2+ 没有增加。此外，我们通过绿色荧光蛋白（GFP）融合蛋白证实了TjZNT1和HRD缺失突变体的亚细胞定位，表明HRD的缺失并不影响TjZNTI的定位。根据这些结果，我们提出 HRD 可能参与 TjZNT1 的离子特异性。 (C) 2008 Elsevier Masson SAS。版权所有。
The Zrt/Irt-like protein (ZIP) family generally contributes to metal homeostasis by regulating cation transport into the cytoplasm. Most ZIP members have a long variable loop between transmembrane domains III and IV, and these loops are predicted to be located in the cytoplasm. The loops contain a histidine-rich domain (HRD) postulated to serve as a metal ion binding site; however, its role has not yet been determined. We previously determined that deletion of the HRD did not affect the Ni tolerance ability of TjZNT1-a ZIP transporter that confers; high Ni tolerance to yeast. In this study, we investigated the effect of HRD deletion on the ion transport ability of TjZNT1. The deletion of HRD increased the specificity for Zn2+, but not for Cd2+. In addition, we confirmed subcellular localizations of TjZNT1 and HRD-deleted mutants by green fluorescence protein (GFP)-fused proteins, indicating that the deletion of HRD did not affect the localization of TjZNTI. From these results, we propose that the HRD could be involved in the ion specificity of TjZNT1. (C) 2008 Elsevier Masson SAS. All rights reserved.