Phosphatidic acid promotes the activation and plasma membrane localization of MKK7 and MKK9 in response to salt stress
Phosphatidic acid promotes the activation and plasma membrane localization of MKK7 and MKK9 in response to salt stress
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磷脂酸促进 MKK7 和 MKK9 的激活和质膜定位以响应盐胁迫
DOI：
10.1016/j.plantsci.2019.110190
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发表时间：
2019
期刊：
影响因子：
5.2
通讯作者：
Zhang Wenhua
中科院分区：
文献类型：
--
作者：
Shen Like;Zhuang Baocheng;Wu Qi;Zhang Hongsheng;Nie Jianing;Jing Wen;Yang Lele;Zhang Wenhua
磷脂酸（PA）是真核生物中参与细胞内信号转导的脂质次生信使。已经证实，PA通过促进有丝分裂原激活的蛋白激酶6 （MPK6）的激活来介导盐胁迫信号，MPK6可磷酸化Na+/H+逆向转运蛋白SOS1。然而，mpk6上游激酶及其与PA的关系尚不清楚。本研究发现，在六种被测试的darabidopsis丝裂原活化蛋白激酶（MKKs）中，PA特异性结合MKK7和MKK9，使MPK6磷酸化，并促进MKK7/MKK9的活化。通过表型和生理分析，我们发现MKK7和MKK9正调控拟南芥耐盐性，并且在功能上是冗余的。NaCl处理可诱导MKK7/MKK9活性显著升高，这部分与磷脂酶Dα1 （PLDα1）有关。MKK7和MKK9也介导nacl诱导的MPK6的激活。此外，PA或NaCl处理可诱导MKK7/MKK9向质膜易位，而这种易位在pldα1中消失。这些结果表明，在拟南芥对盐胁迫的反应中，PA与MKK7和MKK9结合，增加了它们的激酶活性和质膜定位。与先前发现的PA-MPK6-SOS1通路一起，该机制可能最大化信号转导效率，为脂质信号传导与MAPK级联之间的联系提供了新的见解。
Phosphatidic acid (PA) is a lipid secondary messenger involved in intracellular signaling in eukaryotes. It has been confirmed that PA mediates salt stress signaling by promoting activation of Mitogen-activated Protein Kinase 6 (MPK6) which phosphorylates Na+/H+antiporter SOS1. However, the MPK6-upstream kinases and their relationship to PA remain unclear. Here, we found that, among the six testedArabidopsisMitogen-activated Protein Kinase Kinases (MKKs), PA specifically bound to MKK7 and MKK9 which phosphorylate MPK6, and promoted the activation of MKK7/MKK9. Based on phenotypic and physiological analyses, we found that MKK7 and MKK9 positively regulate Arabidopsis salt tolerance and are functionally redundant. NaCl treatment can induce significant increase in MKK7/MKK9 activities, and this depends, in part, on the Phospholipase Dα1 (PLDα1). MKK7 and MKK9 also mediate the NaCl-induced activation of MPK6. Furthermore, PA or NaCl treatment could induce translocation of MKK7/MKK9 to the plasma membrane, whereas this translocation disappeared inpldα1. These results indicate that PA binds to MKK7 and MKK9, increases their kinase activity and plasma membrane localization during Arabidopsis response to salt stress. Together with the PA-MPK6-SOS1 pathway identified previously, this mechanism may maximize the signal transduction efficiency, providing novel insights into the link between lipid signaling and MAPK cascade.