The Arabidopsis metal tolerance protein AtMTP3 maintains metal homeostasis by mediating Zn exclusion from the shoot under Fe deficiency and Zn oversupply
The Arabidopsis metal tolerance protein AtMTP3 maintains metal homeostasis by mediating Zn exclusion from the shoot under Fe deficiency and Zn oversupply
复制标题
拟南芥金属耐受性蛋白 AtMTP3 在铁缺乏和锌过量供应条件下通过介导锌从芽中排除来维持金属平衡
DOI：
10.1111/j.1365-313x.2006.02746.x
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发表时间：
2006-06-01
期刊：
影响因子：
7.2
通讯作者：
Kraemer, Ute
中科院分区：
文献类型：
--
作者：
Arrivault, Stephanie;Senger, Toralf;Kraemer, Ute
维持多种蛋白质的生物活性需要锌离子。然而，当错误定位或过量积累时，Zn2+ 离子会产生毒性，因为它会偶然与蛋白质结合，并从其结合位点置换其他金属离子（其中包括 Fe2+）。在芽殖酵母的 zrc1 cot1 突变体中异源表达先前未表征的拟南芥金属耐受蛋白 MTP3，可恢复对锌和钴的耐受性和细胞积累。当在拟南芥中表达时，MTP3-GFP 融合蛋白定位于液泡膜。 MTP3 的异位过度表达增加了拟南芥根和莲座叶中锌的积累，并增强了锌的耐受性。将野生型植物暴露于高但无毒浓度的 Zn 或 Co 或 Fe 缺乏中，会强烈诱导 MTP3 表达，特别是在根毛区的表皮和皮层细胞中。通过 RNA 干扰沉默 MTP3 会导致锌过敏，并增强土壤生长植物和暴露于过量锌或缺铁的幼苗的地上器官中锌的积累。我们的数据表明，在野生型拟南芥中，AtMTP3 蛋白有助于基本的细胞锌耐受性并控制锌分配，特别是在锌大量流入根共质的条件下。
Zinc ions are required to maintain the biological activity of numerous proteins. However, when mislocalized or accumulated in excess, Zn2+ ions are toxic because of adventitious binding to proteins and displacement of other metal ions, among them Fe2+, from their binding sites. Heterologous expression of a previously uncharacterized Arabidopsis thaliana metal tolerance protein, MTP3, in the zrc1 cot1 mutant of budding yeast restores tolerance to, and cellular accumulation of, zinc and cobalt. An MTP3-GFP fusion protein localizes to the vacuolar membrane when expressed in Arabidopsis. Ectopic over-expression of MTP3 increases Zn accumulation in both roots and rosette leaves of A. thaliana, and enhances Zn tolerance. Exposure of wild-type plants to high but non-toxic concentrations of Zn or Co, or Fe deficiency, strongly induce MTP3 expression specifically in epidermal and cortex cells of the root hair zone. Silencing of MTP3 by RNA interference causes Zn hypersensitivity and enhances Zn accumulation in above-ground organs of soil-grown plants and of seedlings exposed to excess Zn or to Fe deficiency. Our data indicate that, in wild-type A. thaliana, the AtMTP3 protein contributes to basic cellular Zn tolerance and controls Zn partitioning, particularly under conditions of high rates of Zn influx into the root symplasm.