Phosphatidic Acid Regulates BZR1 Activity and Brassinosteroid Signal of Arabidopsis
Phosphatidic Acid Regulates BZR1 Activity and Brassinosteroid Signal of Arabidopsis
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磷脂酸调节拟南芥 BZR1 活性和油菜素类固醇信号
DOI：
10.1093/mp/sst138
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发表时间：
2014
期刊：
影响因子：
27.5
通讯作者：
Lin WH
中科院分区：
文献类型：
--
作者：
Wu P;Gao HB Xue HW;Zhang LL;Xue HW;Lin WH
亲爱的编辑，类胡萝卜素（BR）是一种重要的激素，在植物生长和发育中起着至关重要的作用（Kim和Wang，2010）。遗传学研究确定了许多参与BR信号传导的组分，包括转录因子BZR 1（BRASSINAZOLE RESISTANT 1）。BZR 1被去磷酸化（He等人，2005）来调节靶基因的表达。BZR 1 PEST结构域中的单个氨基酸突变导致PP 2A的结合和去磷酸化增强（蛋白磷酸酶2A; Tang等，2011），导致在功能获得性突变体bzr 1 -1D中组成性激活BZR 1和增强的BR信号。虽然BR信号在拟南芥中已被很好地表征，但BR信号转导通路的各个组成部分是如何被调控的还需要进一步阐明。最近的研究表明，信号分子磷脂酸（PA）主要由磷脂酶D（PLD）和二酰基甘油（DAG）激酶（DGK）产生（Wang et al.，2006），在植物对环境刺激的反应和囊泡运输调节中起关键作用（Testerink和Munnik，2011）。PA通过改变膜结构或结合靶蛋白发挥功能，并且与PA的相互作用影响PA结合蛋白的活性或亚细胞位置（Zhang et al.，2004年）。PLD衍生的PA增加膜PP 2A活性，同时通过结合PP 2AA 1亚基降低总PP 2A活性（Gao et al.，2013年）。PA-PP 2AA 1亚基的结合导致细胞质中PP 2A活性降低;因此，我们使用含有pBZR 1：：BZR 1：：CFP构建体的转基因系W2 C研究PA是否调节BZR 1活性。蛋白质印迹分析显示PA处理后去磷酸化BZR 1的比率降低（图1A，BR处理作为阳性对照），表明BZR 1活性降低。BZR 1活性标记基因CPD的qRT-PCR分析（组成
Dear Editor, Brassinosteroid (BR) is an important hormone and plays crucial roles in plant growth and development (Kim and Wang, 2010). Genetics studies identify many components involving in BR signaling, including transcript factor BZR1 (BRASSINAZOLE RESISTANT 1). BZR1 is dephosphorylated (He et al., 2005) to regulate expression of target genes. A single amino acid mutation in BZR1 PEST domain results in enhanced binding and dephosphorylation by PP2A (PROTEIN PHOSPHATASE 2A; Tang et al., 2011), leading to constitutively activated BZR1 and enhanced BR signal in gain-of-function mutant bzr1-1D. Although BR signal is well characterized in Arabidopsis, how the components of BR signaling transduction pathway are regulated needs further illustrations. Recent studies showed signaling molecule phosphatidic acid (PA), which is mainly produced by Phospholipase D (PLD) and Diacylglycerol (DAG) kinase (DGK)(Wang et al., 2006), plays key roles in plant responses to environmental stimulus and vesicular trafficking regulation (Testerink and Munnik, 2011). PA exerts functions by altering membrane structure or binding target proteins, and interaction with PA affects the activity or subcellular location of PA-binding proteins (Zhang et al., 2004). PLD-derived PA increases membrane PP2A activity while it decreases total PP2A activity through binding PP2AA1 subunit (Gao et al., 2013). Binding of PA-PP2AA1 subunit results in decreased PP2A activity in cytoplasm; we thus investigate whether PA regulates BZR1 activity using transgenic line, W2C, which harbors the pBZR1:: BZR1:: CFP construct. Western blot analysis showed the ratio of dephosphorylated BZR1 was decreased after PA treatment (Figure 1A, BR treatment as positive control), indicating decreased BZR1 activity. qRT–PCR analysis of BZR1 activity marker genes CPD (CONSTITUTIVE