The TOR Pathway Modulates the Structure of Cell Walls in Arabidopsis
The TOR Pathway Modulates the Structure of Cell Walls in Arabidopsis
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DOI：
10.1105/tpc.109.073007
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发表时间：
2010-06-01
期刊：
影响因子：
11.6
通讯作者：
Ringli, Christoph
中科院分区：
文献类型：
--
作者：
Leiber, Ruth-Maria;John, Florian;Ringli, Christoph
植物细胞生长受到细胞壁延伸的限制，这需要以受控的方式合成和重排细胞壁组分。雷帕霉素靶蛋白（TOR）通路是真核生物细胞生长的主要调节因子，雷帕霉素对该通路的抑制会降低细胞生长。在这里，我们表明，在植物中，TOR通路影响细胞壁结构。LRR-延伸蛋白1（LRX 1）是拟南芥根毛中参与细胞壁形成的胞外蛋白，LRX 1突变体发育异常根毛。rol 5（代表lrx 1的阻遏物）被鉴定为lrx 1的阻遏物。酵母中功能相似的ROL 5同源物Ncs 6p（需要Cla 4才能生存6）先前被发现影响TOR信号传导。雷帕霉素抑制TOR信号传导导致抑制lrx 1突变体表型，并引起细胞壁半乳聚糖/鼠李糖半乳糖醛酸-I和阿拉伯半乳聚糖蛋白组分的特异性变化，这些变化与rol 5突变体中观察到的相似。ROL 5蛋白在线粒体中积累，线粒体是TOR途径的靶点和活性氧（ROS）的主要来源，并且rol 5突变体显示出对ROS的反应改变。这表明ROL 5可能作为TOR途径的线粒体组分发挥作用，影响植物对ROS的反应。
Plant cell growth is limited by the extension of cell walls, which requires both the synthesis and rearrangement of cell wall components in a controlled fashion. The target of rapamycin (TOR) pathway is a major regulator of cell growth in eukaryotes, and inhibition of this pathway by rapamycin reduces cell growth. Here, we show that in plants, the TOR pathway affects cell wall structures. LRR-extensin1 (LRX1) of Arabidopsis thaliana is an extracellular protein involved in cell wall formation in root hairs, and lrx1 mutants develop aberrant root hairs. rol5 (for repressor of lrx1) was identified as a suppressor of lrx1. The functionally similar ROL5 homolog in yeast, Ncs6p (needs Cla4 to survive 6), was previously found to affect TOR signaling. Inhibition of TOR signaling by rapamycin led to suppression of the lrx1 mutant phenotype and caused specific changes to galactan/rhamnogalacturonan-I and arabinogalactan protein components of cell walls that were similar to those observed in the rol5 mutant. The ROL5 protein accumulates in mitochondria, a target of the TOR pathway and major source of reactive oxygen species (ROS), and rol5 mutants show an altered response to ROS. This suggests that ROL5 might function as a mitochondrial component of the TOR pathway that influences the plant's response to ROS.