N-terminal motifs in some plant disease resistance proteins function in membrane attachment and contribute to disease resistance.
N-terminal motifs in some plant disease resistance proteins function in membrane attachment and contribute to disease resistance.
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DOI：
10.1094/mpmi-11-10-0272
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发表时间：
2012-02
期刊：
影响因子：
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通讯作者：
D. Takemoto;Maryam Rafiqi;U. Hurley;G. Lawrence;Maud Bernoux;A. Hardham;J. Ellis;P. Dodds;David A Jones
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文献类型：
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作者：
D. Takemoto;Maryam Rafiqi;U. Hurley;G. Lawrence;Maud Bernoux;A. Hardham;J. Ellis;P. Dodds;David A Jones
为了研究植物抗病蛋白N端结构域在膜靶向中的作用，利用共聚焦显微镜将拟南芥和亚麻抗病蛋白的N端融合到绿色荧光蛋白（GFP）和植物中定位的融合蛋白上。拟南芥RPP1-WsB和RPS5抗性蛋白的N端以及RPS5抗性所需的PBS1蛋白将GFP靶向质膜，预测的肉豆肉酰化和潜在的棕榈酰化位点的突变导致其向核胞浆定位转变。拟南芥RPS2抗性蛋白的n端结构域不完全靶向质膜。相比之下，携带预测信号锚点的拟南芥RPP1-WsA和亚麻L6和M抗性蛋白的n端结构域定位于细胞膜系统，RPP1-WsA定位于内质网和高尔基体，L6定位于高尔基体，M定位于细胞质体。全长L6也针对高尔基体。通过对L6和M的信号锚域的6个非保守氨基酸残基进行定点诱变，将L6 n端融合蛋白的定位改变为M的定位，反之亦然，表明这些残基控制着信号锚的靶向特异性。用M代替L6的信号锚定域对表达AvrL567的亚麻锈病的L6蛋白积累和抗性没有影响，但信号锚定域的去除降低了L6蛋白的积累和对L6的抗性，这表明L6蛋白的稳定需要膜附着。
To investigate the role of N-terminal domains of plant disease resistance proteins in membrane targeting, the N termini of a number of Arabidopsis and flax disease resistance proteins were fused to green fluorescent protein (GFP) and the fusion proteins localized in planta using confocal microscopy. The N termini of the Arabidopsis RPP1-WsB and RPS5 resistance proteins and the PBS1 protein, which is required for RPS5 resistance, targeted GFP to the plasma membrane, and mutation of predicted myristoylation and potential palmitoylation sites resulted in a shift to nucleocytosolic localization. The N-terminal domain of the membrane-attached Arabidopsis RPS2 resistance protein was targeted incompletely to the plasma membrane. In contrast, the N-terminal domains of the Arabidopsis RPP1-WsA and flax L6 and M resistance proteins, which carry predicted signal anchors, were targeted to the endomembrane system, RPP1-WsA to the endoplasmic reticulum and the Golgi apparatus, L6 to the Golgi apparatus, and M to the tonoplast. Full-length L6 was also targeted to the Golgi apparatus. Site-directed mutagenesis of six nonconserved amino acid residues in the signal anchor domains of L6 and M was used to change the localization of the L6 N-terminal fusion protein to that of M and vice versa, showing that these residues control the targeting specificity of the signal anchor. Replacement of the signal anchor domain of L6 by that of M did not affect L6 protein accumulation or resistance against flax rust expressing AvrL567 but removal of the signal anchor domain reduced L6 protein accumulation and L6 resistance, suggesting that membrane attachment is required to stabilize the L6 protein.