The Arabidopsis RING E3 Ubiquitin Ligase AtAIRP3/LOG2 Participates in Positive Regulation of High-Salt and Drought Stress Responses
The Arabidopsis RING E3 Ubiquitin Ligase AtAIRP3/LOG2 Participates in Positive Regulation of High-Salt and Drought Stress Responses
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DOI：
10.1104/pp.113.220103
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发表时间：
2013-07-01
期刊：
影响因子：
7.4
通讯作者：
Kim, Woo Taek
中科院分区：
文献类型：
--
作者：
Kim, Jong Hum;Kim, Woo Taek
真正有趣的新基因（RING）E3泛素连接酶与高等植物对胁迫激素脱落酸（阿坝）以及环境胁迫的细胞反应有关。在这里，ABA不敏感的RING蛋白3（atairp 3）功能丧失突变株系在拟南芥（拟南芥）中分离，由于其低敏感性阿坝在其萌发阶段相比，野生型植物。AtAIRP 3含有一个C3 HC 4型RING基序、一个豆蔻酰化位点和一个与RING 2（DAR 2）结构域相关的结构域。出乎意料的是，AtAIRP 3被鉴定为GDU 2丢失（LOG 2），最近显示其通过与谷氨酰胺转运蛋白1相互作用参与氨基酸输出系统。因此，AtAIRP 3被重命名为AtAIRP 3/LOG 2。AtAIRP 3/LOG 2的转录水平上调干旱，高盐，阿坝，这表明该因子在非生物胁迫响应的作用。atairp 3/log 2 -2基因敲除突变体和35 S：Atairp 3-RNAi基因敲除转基因植株表现出ABA介导的种子萌发和气孔关闭受损。共抑制和互补研究进一步支持了AtAIRP 3/LOG 2在阿坝反应中的积极作用。相对于野生型植物，AtAIRP 3/LOG 2的抑制导致对高盐和缺水显着的超敏感表型。这些结果表明拟南芥RING E3 AtAIRP 3/LOG 2是ABA介导的干旱和盐胁迫耐受机制的正调控因子。使用酵母（酿酒酵母）双杂交，在体外，在体内免疫沉淀，无细胞蛋白降解，并在体外泛素化测定，响应脱水21被确定为AtAIRP 3/LOG 2的底物蛋白。总的来说，我们的数据表明，AtAIRP 3/LOG 2在ABA介导的干旱胁迫反应中发挥双重功能，并在拟南芥的氨基酸输出途径。
Really Interesting New Gene (RING) E3 ubiquitin ligases have been implicated in cellular responses to the stress hormone abscisic acid (ABA) as well as to environmental stresses in higher plants. Here, an ABA-insensitive RING protein3 (atairp3) loss-of-function mutant line in Arabidopsis (Arabidopsis thaliana) was isolated due to its hyposensitivity to ABA during its germination stage as compared with wildtype plants. AtAIRP3 contains a single C3HC4-type RING motif, a putative myristoylation site, and a domain associated with RING2 (DAR2) domain. Unexpectedly, AtAIRP3 was identified as LOSS OF GDU2 (LOG2), which was recently shown to participate in an amino acid export system via interaction with GLUTAMINE DUMPER1. Thus, AtAIRP3 was renamed as AtAIRP3/LOG2. Transcript levels of AtAIRP3/LOG2 were up-regulated by drought, high salinity, and ABA, suggesting a role for this factor in abiotic stress responses. The atairp3/log2-2 knockout mutant and 35S:AtAIRP3-RNAi knockdown transgenic plants displayed impaired ABA-mediated seed germination and stomata closure. Cosuppression and complementation studies further supported a positive role for AtAIRP3/LOG2 in ABA responses. Suppression of AtAIRP3/LOG2 resulted in marked hypersensitive phenotypes toward high salinity and water deficit relative to wild-type plants. These results suggest that Arabidopsis RING E3 AtAIRP3/LOG2 is a positive regulator of the ABA-mediated drought and salt stress tolerance mechanism. Using yeast (Saccharomyces cerevisiae) two-hybrid, in vitro, and in vivo immunoprecipitation, cell-free protein degradation, and in vitro ubiquitination assays, RESPONSIVE TO DEHYDRATION21 was identified as a substrate protein of AtAIRP3/LOG2. Collectively, our data suggest that AtAIRP3/LOG2 plays dual functions in ABA-mediated drought stress responses and in an amino acid export pathway in Arabidopsis.