Uncertainty of EIN2(Ser645/Ser924) Inactivation by CTR1-Mediated Phosphorylation Reveals the Complexity of Ethylene Signaling.
Uncertainty of EIN2(Ser645/Ser924) Inactivation by CTR1-Mediated Phosphorylation Reveals the Complexity of Ethylene Signaling.
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CTR1 介导的磷酸化导致 EIN2Ser645/Ser924 失活的不确定性揭示了乙烯信号传导的复杂性
DOI：
10.1016/j.xplc.2020.100046
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发表时间：
2020-05-11
影响因子：
10.5
通讯作者：
Wen CK
中科院分区：
文献类型：
--
作者：
Zhang J;Chen Y;Lu J;Zhang Y;Wen CK
乙烯INSENSITIVE2(EIN2)是乙烯信号转导的关键成分，在无乙烯的情况下，当Ser645和Ser924被Raf样三联反应1(CTR1)磷酸化时，EIN2的活性被抑制。乙烯阻止CTR1的活性，从而阻止EIN2Ser645/Ser924的磷酸化，蛋白质降解的EIN2 C末端(EIN2-C)从内质网到细胞核和加工体的亚细胞运输触发乙烯信号转导。在这里，我们报告了EIN2激活的乙烯信号的意外复杂性。在没有CTR1介导的负调控的情况下，EIN2的激活在一定程度上需要乙烯。Ein2突变体得到了编码EIN2的转基因的补充，EIN2变种具有阻止或模拟Ser645/Ser924磷酸化或EIN2-C的突变；所有携带这些EIN2衍生转基因的转基因株对乙烯都有反应。此外，我们发现荧光蛋白标记的EIN2及其变体几乎不受乙烯的影响，并且呈现出相似的亚细胞分布模式：在胞浆颗粒和核斑点中。值得注意的是，EIN2蛋白在N端或C端与荧光蛋白融合的亚细胞定位模式相似，而EIN2-C-YFP主要在胞浆中观察到，而在细胞核中没有。Western blotts和MS分析表明，EIN2具有很高的复杂性，很可能被蛋白质分解为多个片段。我们的结果提示EIN2全长的核定位，EIN2Ser645/Ser924磷酸化状态与乙烯信号的弱关联，以及EIN2及其蛋白降解产物在不同亚细胞中引起的乙烯信号的复杂性。我们提出了一个替代模型来解释EIN2激活的乙烯信号。本研究发现EIN2、低磷酸化的EIN2AA和磷酸化的EIN2DD/EIN2EE变体都对乙烯有反应，它们在细胞质和细胞核中的亚细胞分布特征相似，表明EIN2具有很高的蛋白质复杂性。此外，EIN2Ser645/Ser924的磷酸化状态不太可能与乙烯信号激活有关，某些种类的EIN2-C裂解产物负责乙烯信号转导，这导致了另一种解释乙烯信号转导的模型的提出。
ETHYLENE INSENSITIVE2 (EIN2) is a key component of ethylene signaling whose activity is inhibited upon phosphorylation of Ser645 and Ser924 by the Raf-like CONSTITUTIVE TRIPLE-RESPONSE 1 (CTR1) in the absence of ethylene. Ethylene prevents CTR1 activity and thus EIN2Ser645/Ser924 phosphorylation, and subcellular trafficking of a proteolytically cleaved EIN2 C terminus (EIN2-C) from the endoplasmic reticulum to the nucleus and processing bodies triggers ethylene signaling. Here, we report an unexpected complexity of EIN2-activated ethylene signaling. EIN2 activation in part requires ethylene in the absence of CTR1-mediated negative regulation. The ein2 mutant was complemented by the transgenes encoding EIN2, EIN2 variants with mutations that either prevent or mimic Ser645/Ser924 phosphorylation, or EIN2-C; and all the transgenic lines carrying these EIN2-derived transgenes responded to ethylene. Furthermore, we found that the fluorescence protein-tagged EIN2 and its variants were affected little by ethylene and exhibited similar subcellular distribution patterns: in the cytosolic particles and nuclear speckles. Of note, the subcellular localization patterns of EIN2 proteins fused with a fluorescence protein either at the N or C terminus were similar, whereas EIN2-C-YFP was primarily observed in the cytosol but not in the nucleus. Western blots and mass spectrum analyses suggested a high complexity of EIN2, which is likely proteolytically processed into multiple fragments. Our results suggested a nuclear localization of the full-length EIN2, weak association of the EIN2Ser645/Ser924 phosphorylation status and ethylene signaling, and the complexity of ethylene signaling caused by EIN2 and its proteolytic products in different subcellular compartments. We propose an alternative model to explain EIN2-activated ethylene signaling. This study discovered that EIN2, the underphosphorylated EIN2AA, and phosphomimic EIN2DD/EIN2EE variants are all responsive to ethylene, and their subcellular distribution features in the cytosol and nucleus are similar, indicating a high protein complexity of EIN2. Furthermore, it was demonstrated that EIN2Ser645/Ser924 phosphorylation status is unlikely to be associated with ethylene signaling activation, and certain species of EIN2-C cleavage products are responsible for ethylene signaling, leading to a proposal of an alternative model explaining ethylene signaling.
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影响因子：
2.9
作者：
Shakeel SN;Wang X;Binder BM;Schaller GE
通讯作者：
Schaller GE
影响因子：
--
作者：
Chen, Ruiqiang;Binder, Brad M.;Cooper, Bret
通讯作者：
Cooper, Bret
影响因子：
7.2
作者：
Huang, YF;Li, H;Kieber, JJ
通讯作者：
Kieber, JJ
影响因子：
27.5
作者：
Bisson, Melanie M. A.;Groth, Georg
通讯作者：
Groth, Georg
DOI：
10.1126/science.1225974
发表时间：
2012-10-19
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Qiao H;Shen Z;Huang SS;Schmitz RJ;Urich MA;Briggs SP;Ecker JR
通讯作者：
Ecker JR