Two p-type ATPases are required for copper delivery in Arabidopsis thaliana chloroplasts
Two p-type ATPases are required for copper delivery in Arabidopsis thaliana chloroplasts
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DOI：
10.1105/tpc.104.030452
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发表时间：
2005-04-01
期刊：
影响因子：
11.6
通讯作者：
Shikanai, T
中科院分区：
文献类型：
--
作者：
Abdel-Ghany, SE;Müller-Moulé, P;Shikanai, T
铜传递到类囊体腔蛋白质质体蓝素和叶绿体中的基质酶Cu/Zn超氧化物歧化酶是光合作用和氧化应激保护所必需的。通过对拟南芥铜转运蛋白基因功能的分析，对叶绿体铜转运系统进行了表征。两个突变等位基因被确定为以前未知的基因，PAA 2（拟南芥P型ATP酶），这是需要有效的光合电子传递。PAA 2编码一个与PAA 1序列相似的铜转运P型ATP酶，在叶绿体铜转运中发挥作用。这两种蛋白质定位于叶绿体，如与绿色荧光蛋白融合所示。PAA 1融合被发现在叶绿体周边，而PAA 2融合定位在类囊体膜。paa 1和paa 2突变体的表型表明，这两种转运蛋白具有不同的功能：而这两种转运蛋白都需要铜传递到质体蓝素，铜传递到基质中只在paa 1中受到抑制，而在paa 2中不受抑制。paa 1和paa 2对超氧化物歧化酶亚型表达水平的影响表明，基质铜水平调节核基因铁超氧化物歧化酶1和铜/锌超氧化物歧化酶2的表达。一个paa 1 paa 2双突变体是幼苗致死的，强调了铜对光合作用的重要性。我们建议，PAA 1和PAA 2功能顺序铜运输的信封和类囊体膜，分别。
Copper delivery to the thylakoid lumen protein plastocyanin and the stromal enzyme Cu/Zn superoxide dismutase in chloroplasts is required for photosynthesis and oxidative stress protection. The copper delivery system in chloroplasts was characterized by analyzing the function of copper transporter genes in Arabidopsis thaliana. Two mutant alleles were identified of a previously uncharacterized gene, PAA2 (for P-type ATPase of Arabidopsis), which is required for efficient photosynthetic electron transport. PAA2 encodes a copper-transporting P-type ATPase with sequence similarity to PAA1, which functions in copper transport in chloroplasts. Both proteins localized to the chloroplast, as indicated by fusions to green fluorescent protein. The PAA1 fusions were found in the chloroplast periphery, whereas PAA2 fusions were localized in thylakoid membranes. The phenotypes of paa1 and paa2 mutants indicated that the two transporters have distinct functions: whereas both transporters are required for copper delivery to plastocyanin, copper delivery to the stroma is inhibited only in paa1 but not in paa2. The effects of paa1 and paa2 on superoxide dismutase isoform expression levels suggest that stromal copper levels regulate expression of the nuclear genes IRON SUPEROXIDE DISMUTASE1 and COPPER/ZINC SUPEROXIDE DISMUTASE2. A paa1 paa2 double mutant was seedling-lethal, underscoring the importance of copper to photosynthesis. We propose that PAA1 and PAA2 function sequentially in copper transport over the envelope and thylakoid membrane, respectively.