A role for ETR1 in hydrogen peroxide signaling in stomatal guard cells
A role for ETR1 in hydrogen peroxide signaling in stomatal guard cells
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DOI：
10.1104/pp.104.056994
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发表时间：
2005-03-01
期刊：
影响因子：
7.4
通讯作者：
Neill, SJ
中科院分区：
文献类型：
--
作者：
Desikan, R;Hancock, JT;Neill, SJ
通过氧化还原活性分子过氧化氢（H2 O2）的信号传导对于植物中的几个过程是重要的，例如气孔关闭、根生长、向重力性和对病原体攻击的响应（Neill等人，2002; Laloi等人，2004年）。尽管已经提出蛋白质内反应性Cys残基的氧化修饰是H2 O2信号传导可以激活诸如基因表达和可逆蛋白质磷酸化的应答的手段（库珀et al.，2002; Danon，2002），H2 O2感知与细胞内信号传导的联系仍有待阐明。在这里，我们报告的遗传和生理数据表明，以前未知的功能拟南芥（拟南芥）乙烯受体ETR 1，介导H2 O2信号在气孔保卫细胞。功能丧失的etr 1 -7突变体中的气孔不响应于H2 O2而关闭，ETR 1的N-末端区域中的Cys残基的突变破坏了植物和酵母中的H2 O2信号传导（酿酒酵母）。H2 O2-的大规模分析拟南芥和烟草中的基因表达调控表明，编码双组分信号转导途径和乙烯信号传导元件的基因表达被外源H2 O2上调（Desikan等人，2001; Vandenabeele等人，2003年），这表明这些现象可能是有联系的。His激酶（HK）是将环境信号转化为细胞反应的双组分系统的一部分。已知它们中的一些在植物中用作细胞分裂素和乙烯受体（Hwang et al.，2002年）。杂交HK由N末端信号输入结构域（其中一些具有疏水性跨膜区，例如ETR 1）、HK结构域和C末端反应调节结构域组成。在典型的HK信号传导过程中，HK结构域在His残基上自磷酸化，随后在响应中磷酸基团转移到Asp残基上。
Signaling through the redox active molecule hydrogen peroxide (H2O2) is important for several processes in plants, such as stomatal closure, root growth, gravitropism, and responses to pathogen challenge (Neill et al., 2002; Laloi et al., 2004). Although oxidative modification of reactive Cys residues within proteins has been suggested as a means by which H2O2 signaling can activate responses such as gene expression and reversible protein phosphorylation (Cooper et al., 2002; Danon, 2002), the linkage of H2O2 perception to intracellular signaling remains to be elucidated. Here, we report genetic and physiological data that demonstrate a previously uncharacterized function for the Arabidopsis (Arabidopsis thaliana) ethylene receptor ETR1, that of mediating H2O2 signaling in stomatal guard cells. Stomata in the loss-of-function etr1-7 mutant do not close in response to H2O2, and mutation of a Cys residue in the N-terminal region of ETR1 disrupts H2O2 signaling in both plants and in yeast (Saccharomyces cerevisiae).Large-scale analyses of H2O2-modulated gene expression in Arabidopsis and tobacco have shown that expression of genes encoding elements of both twocomponent signal transduction pathways and ethylene signaling are up-regulated by exogenous H2O2 (Desikan et al., 2001; Vandenabeele et al., 2003), suggesting that these phenomena may be linked. His kinases (HKs) are part of two-component systems that transduce environmental signals into cellular responses. Some of them are known to function as cytokinin and ethylene receptors in plants (Hwang et al., 2002). Hybrid HKs consist of an N-terminal signal input domain (with some having hydrophobic transmembrane regions, such as ETR1), a HK domain, and a C-terminal response regulator domain. During typical HK signaling, the HK domain is autophosphorylated on a His residue, with subsequent transfer of the phosphate group onto an Asp residue in the response