A rice tonoplastic calcium exchanger, OsCCX2 mediates Ca2+/cation transport in yeast.
A rice tonoplastic calcium exchanger, OsCCX2 mediates Ca2+/cation transport in yeast.
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DOI：
10.1038/srep17117
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发表时间：
2015-11-26
影响因子：
4.6
通讯作者：
Pandey GK
中科院分区：
文献类型：
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作者：
Yadav AK;Shankar A;Jha SK;Kanwar P;Pandey A;Pandey GK
在植物细胞中，细胞内的阳离子梯度是通过各种交换剂、泵和通道的协同作用来维持的。拟南芥交换蛋白家族成员AtCCX 3和AtCCX 5属于CaCA（钙阳离子交换蛋白）超家族，而水稻CCXs的阳离子转运活性至今尚未被研究。水稻基因组编码4个CCXs，只有OsCCX 2在非生物胁迫和Ca ~（2+）饥饿条件下表达差异。OsCCX 2定位于液泡膜，并在过量CaCl 2条件下抑制K667（低亲和力Ca 2+摄取缺陷）酵母突变体的Ca 2+敏感性。与AtCCXs相反，表达OsCCX 2的K667酵母细胞显示出对过量Na+、Li+、Fe 2+、Zn 2+和Co2+的耐受性，并表明其在酵母中转运一价和二价阳离子的能力。此外，与先前表征的AtCCXs相反，OsCCX 2不能补充酵母trk 1 trk 2双突变体，表明不能在酵母系统中转运K+。这些发现表明OsCCX 2具有不同于先前表征的植物CCXs的金属转运特性。OsCCX 2可作为增强植物非生物胁迫耐受性和重金属污染土壤植物修复的潜在候选基因。
In plant cell, cations gradient in cellular compartments is maintained by synergistic action of various exchangers, pumps and channels. The Arabidopsis exchanger family members (AtCCX3 and AtCCX5) were previously studied and belong to CaCA (calcium cation exchangers) superfamily while none of the rice CCXs has been functionally characterized for their cation transport activities till date. Rice genome encode four CCXs and only OsCCX2 transcript showed differential expression under abiotic stresses and Ca2+ starvation conditions. The OsCCX2 localized to tonoplast and suppresses the Ca2+ sensitivity of K667 (low affinity Ca2+ uptake deficient) yeast mutant under excess CaCl2 conditions. In contrast to AtCCXs, OsCCX2 expressing K667 yeast cells show tolerance towards excess Na+, Li+, Fe2+, Zn2+ and Co2+ and suggest its ability to transport both mono as well as divalent cations in yeast. Additionally, in contrast to previously characterized AtCCXs, OsCCX2 is unable to complement yeast trk1trk2 double mutant suggesting inability to transport K+ in yeast system. These finding suggest that OsCCX2 having distinct metal transport properties than previously characterized plant CCXs. OsCCX2 can be used as potential candidate for enhancing the abiotic stress tolerance in plants as well as for phytoremediation of heavy metal polluted soil.