Arabidopsis C3HC4-RING finger E3 ubiquitin ligase AtAIRP4 positively regulates stress-responsive abscisic acid signaling.
Arabidopsis C3HC4-RING finger E3 ubiquitin ligase AtAIRP4 positively regulates stress-responsive abscisic acid signaling.
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DOI：
10.1111/jipb.12364
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发表时间：
2016
影响因子：
11.4
通讯作者：
Liang Yang;Qiaohong Liu;Zhibin Liu;Hao Yang;Jianmei Wang;Xu-feng Li;Yi Yang
中科院分区：
文献类型：
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作者：
Liang Yang;Qiaohong Liu;Zhibin Liu;Hao Yang;Jianmei Wang;Xu-feng Li;Yi Yang
通过泛素系统降解蛋白质是植物许多逆境信号通路中的重要步骤。E3连接酶识别配基蛋白，决定了蛋白质降解的高度特异性，因此在泛素化过程中起着关键作用。在此，我们克隆了一个基因，命名为拟南芥脱落酸(ABA)不敏感环蛋白4(AtAIRP4)，该基因受ABA和其他胁迫处理的诱导。AtAIRP4编码一种C末端带有C3HC4环指结构域的细胞蛋白，在体外具有E3连接酶活性。AtAIRP4基因的缺失导致根伸长和气孔关闭对ABA的敏感性降低，而该基因在T-DNA插入突变体atairp4中的过表达有效地恢复了ABA相关的表型。与野生型和atairp4突变体相比，atAIRP4高表达植株在种子萌发过程中对盐和渗透胁迫高度敏感，并表现出抗旱能力。此外，在AtAIRP4高表达植株中，ABA和干旱诱导标记基因的表达水平显著高于野生型和atairp4突变植株。因此，这些结果表明，AtAIRP4可能是ABA介导的拟南芥干旱回避的正调控因子和耐盐性的负调控因子。
Degradation of proteins via the ubiquitin system is an important step in many stress signaling pathways in plants. E3 ligases recognize ligand proteins and dictate the high specificity of protein degradation, and thus, play a pivotal role in ubiquitination. Here, we identified a gene, named Arabidopsis thaliana abscisic acid (ABA)-insensitive RING protein 4 (AtAIRP4), which is induced by ABA and other stress treatments. AtAIRP4 encodes a cellular protein with a C3HC4-RING finger domain in its C-terminal side, which has in vitro E3 ligase activity. Loss of AtAIRP4 leads to a decrease in sensitivity of root elongation and stomatal closure to ABA, whereas overexpression of this gene in the T-DNA insertion mutant atairp4 effectively recovered the ABA-associated phenotypes. AtAIRP4 overexpression plants were hypersensitive to salt and osmotic stresses during seed germination, and showed drought avoidance compared with the wild-type and atairp4 mutant plants. In addition, the expression levels of ABA- and drought-induced marker genes in AtAIRP4 overexpression plants were markedly higher than those in the wild-type and atairp4 mutant plants. Hence, these results indicate that AtAIRP4 may act as a positive regulator of ABA-mediated drought avoidance and a negative regulator of salt tolerance in Arabidopsis.