Reciprocal antagonistic regulation of E3 ligases controls ACC synthase stability and responses to stress
Reciprocal antagonistic regulation of E3 ligases controls ACC synthase stability and responses to stress
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DOI：
10.1073/pnas.2011900118
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发表时间：
2021-08-20
影响因子：
11.1
通讯作者：
Yoon, Gyeong Mee
中科院分区：
文献类型：
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作者：
Lee, Han Yong;Park, Hye Lin;Yoon, Gyeong Mee
乙烯通过与其他植物激素的串扰影响植物的生长、发育和逆境反应；然而，潜在的分子机制仍不清楚。在这里，我们描述了油菜素类固醇(BR)和乙烯生物合成之间的机械联系，它调节细胞蛋白质的动态平衡和应激反应。我们证明，作为支架，1-氨基环丙烷-1-羧酸(ACC)合成酶(ACS)是乙烯生物合成中的限速酶，它促进了含有参与胁迫反应的E3连接酶的环域拟南芥(Sinat)与乙烯过度生产物1(ETO1)和类似ETO1(EOL)蛋白之间的相互作用，E3连接酶适配器针对的是ACS亚型的一部分。每一种E3连接酶促进另一种连接酶的降解，这种相互拮抗的相互作用影响ACS的蛋白质稳定性。此外，14-3-3是一种磷蛋白结合蛋白，以BR依赖的方式与SINAT相互作用，从而激活相互降解。E3连接酶之间相互破坏的降解破坏了植物在缺碳条件下的生存。我们的研究揭示了植物通过调节ACS及其同源E3连接酶的动态平衡来响应胁迫的机制。
Ethylene influences plant growth, development, and stress responses via crosstalk with other phytohormones; however, the underlying molecular mechanisms are still unclear. Here, we describe a mechanistic link between the brassinosteroid (BR) and ethylene biosynthesis, which regulates cellular protein homeostasis and stress responses. We demonstrate that as a scaffold, 1-aminocyclopropane-1-carboxylic acid (ACC) synthases (ACS), a rate-limiting enzyme in ethylene biosynthesis, promote the interaction between Seven-in-Absentia of Arabidopsis (SINAT), a RING-domain containing E3 ligase involved in stress response, and ETHYLENE OVERPRODUCER 1 (ETO1) and ETO1-like (EOL) proteins, the E3 ligase adaptors that target a subset of ACS isoforms. Each E3 ligase promotes the degradation of the other, and this reciprocally antagonistic interaction affects the protein stability of ACS. Furthermore, 14-3-3, a phosphoprotein-binding protein, interacts with SINAT in a BR-dependent manner, thus activating reciprocal degradation. Disrupted reciprocal degradation between the E3 ligases compromises the survival of plants in carbon-deficient conditions. Our study reveals a mechanism by which plants respond to stress by modulating the homeostasis of ACS and its cognate E3 ligases.