Phosphorylation of WHIRLY1 by CIPK14 Shifts Its Localization and Dual Functions in Arabidopsis
Phosphorylation of WHIRLY1 by CIPK14 Shifts Its Localization and Dual Functions in Arabidopsis
复制标题
CIPK14 磷酸化 WHIRLY1 改变其在拟南芥中的定位和双重功能
DOI：
10.1016/j.molp.2017.03.011
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发表时间：
2017-05-01
期刊：
影响因子：
27.5
通讯作者：
Miao, Ying
中科院分区：
文献类型：
--
作者：
Ren, Yujun;Li, Yanyun;Miao, Ying
质体到细胞核的逆行信号对于植物的正常生长和发育至关重要。双功能和双定位的 ssDNA 结合蛋白 WHIRLY1 (WHY1) 已被提出来协调从质体到细胞核的逆行信号传导。然而，控制 WHY1 介导质体到细胞核逆行信号转导的功能开关的调节机制仍然未知。在这里，我们报道了拟南芥中钙调神经磷酸酶 B 样相互作用蛋白激酶 14 (CIPK14) 与 WHY1 相互作用并磷酸化 WHY1。 WHY1 的磷酸化导致细胞核中的积累增加，并增强与 WRKY53 启动子的结合，WRKY53 编码拟南芥中调节叶片衰老的关键转录因子。过表达CIPK14的转基因植物中WHY1的核亚型增加，质体亚型减少，其中95%的转基因品系表现出常绿表型，5%的品系表现出杂色浅绿色表型。有趣的是，两种转基因植物的表型都可以通过质体形式WHY1的过度表达来恢复。相比之下，CIPK14的敲除会导致早期衰老，甚至幼苗死亡的表型，同时衰老相关基因（如WRKY53、SAG12和NDHF）的表达升高，但MER11、RAD50和POR基因的表达降低，这可以通过CIPK14的过表达来挽救，但不能通过质体形式或核形式的WHY1的过表达来挽救；过表达 CIPK14 的常绿植物显示 WRKY53、SAG12、NDHF 和大质体 rRNA 的表达减少。一致地，在 CIPK14 敲除系中，核型 WHY1 的积累显着减少，导致核型/质体型 WHY1 的比例较低。综上所述，我们的结果表明 CIPK14 调节 WHY1 的磷酸化和细胞器分布，并确定 CIPK14 可能充当叶片衰老和质体发育之间的细胞开关，以协调拟南芥中的细胞间信号传导。
Plastid-to-nucleus retrograde signaling is critical for normal growth and development in plants. The dual-function and dual-located ssDNA binding protein WHIRLY1 (WHY1) has been proposed to coordinate the retrograde signaling from plastids to the nucleus. However, the regulatory mechanism governing the functional switch of WHY1 for mediating plastid-to-nucleus retrograde signaling remains unknown. Here, we report that the Calcineurin B-Like-Interacting Protein Kinase14 (CIPK14) interacts with and phosphorylates WHY1 in Arabidopsis. Phosphorylation of WHY1 results in increased accumulation in the nucleus and enhanced binding with the promoter of WRKY53, which encodes a key transcription factor regulating leaf senescence in Arabidopsis. Transgenic plants overexpressing CIPK14 showed an increased nuclear isoform but decreased plastid isoform of WHY1, among which 95% of transgenic lines showed the stay-green phenotype and 5% of lines showed the variegated pale-green phenotype. Interestingly, the phenotypes of both types of transgenic plants could be recovered by overexpression of plastid-form WHY1. In contrast, knockdown of CIPK14 caused early senescence and even seedling-lethal phenotypes along with elevated expression of senescence-related genes such as WRKY53, SAG12, and NDHF but decreased expression of MER11, RAD50, and POR genes, which could be rescued by overexpression of CIPK14 but not by overexpressing plastid-form or nuclear-form WHY1; the stay-green plants overexpressing CIPK14 showed reduced expression of WRKY53, SAG12, NDHF, and large plastid rRNA. Consistently, the accumulation of nuclear-form WHY1 was significantly reduced in the CIPK14 knockdown lines, resulting in a low ratio of nuclear-/plastid- form WHY1. Taken together, our results demonstrate that CIPK14 regulates the phosphorylation and organellar distributions of WHY1 and pinpoint that CIPK14 may function as a cellular switch between leaf senescence and plastid development for coordinating the intercellular signaling in Arabidopsis.