Differential contribution of two peroxisomal protein receptors to the maintenance of peroxisomal functions in Arabidopsis
Differential contribution of two peroxisomal protein receptors to the maintenance of peroxisomal functions in Arabidopsis
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DOI：
10.1074/jbc.m411005200
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发表时间：
2005-04-15
影响因子：
4.8
通讯作者：
Nishimura, M
中科院分区：
文献类型：
--
作者：
Hayashi, M;Yagi, M;Nishimura, M
已知高等植物细胞中的过氧化物酶体根据细胞类型在功能上分化。植物过氧化物酶体因其功能的不同而分为几类，如乙二醛酶体和叶过氧化物酶体。这些过氧化物酶体功能通过输入新合成的蛋白质来维持，所述蛋白质含有称为PTS 1和PTS 2的两种过氧化物酶体靶向信号中的一种。已知这些靶向信号分别被胞质受体Pex 5 p和Pex 7 p识别。为了证明Pex 5 p和Pex 7 p对维持植物中过氧化物酶体功能的贡献，将双链RNA构建体引入拟南芥基因组中。在转基因拟南芥中，通过双链RNA介导的干扰有效地降低了PEX 5和PEX 7基因的表达。Pex 5 p缺陷的拟南芥表现出减少活动的乙醛酸酶体和叶过氧化物酶体的功能。在过表达功能缺陷型Pex 5 p的转基因拟南芥中观察到相同的表型。与此相反，Pex 7 p缺陷的拟南芥表现出降低活性的glyoxysomal功能，但不是叶过氧化物酶体功能。过氧化物酶体蛋白在转基因拟南芥的进口分析表明，Pex 5 p参与进口的PTS 1-含有蛋白质和PTS 2-含有蛋白质，而Pex 7 p的进口，只有PTS 2-含有蛋白质。总体而言，结果表明Pex 5 p和Pex 7 p在维持植物中的乙二醛体和叶过氧化物酶体功能中发挥不同的作用。
Peroxisomes in higher plant cells are known to differentiate in function depending on the cell type. Because of the functional differentiation, plant peroxisomes are subdivided into several classes, such as glyoxysomes and leaf peroxisomes. These peroxisomal functions are maintained by import of newly synthesized proteins containing one of two peroxisomal targeting signals known as PTS1 and PTS2. These targeting signals are known to be recognized by the cytosolic receptors, Pex5p and Pex7p, respectively. To demonstrate the contribution of Pex5p and Pex7p to the maintenance of peroxisomal functions in plants, double-stranded RNA constructs were introduced into the genome of Arabidopsis thaliana. Expression of the PEX5 and PEX7 genes was efficiently reduced by the double-stranded RNA-mediated interference in the transgenic Arabidopsis. The Pex5p-deficient Arabidopsis showed reduced activities for both glyoxysomal and leaf peroxisomal functions. An identical phenotype was observed in a transgenic Arabidopsis overexpressing functionally defective Pex5p. In contrast, the Pex7p-deficient Arabidopsis showed reduced activity for glyoxysomal function but not for leaf peroxisomal function. Analyses of peroxisomal protein import in the transgenic Arabidopsis revealed that Pex5p was involved in import of both PTS1-containing proteins and PTS2-containing proteins, whereas Pex7p contributed to the import of only PTS2-containing proteins. Overall, the results indicated that Pex5p and Pex7p play different roles in the maintenance of glyoxysomal and leaf peroxisomal functions in plants.