Diverse nitrogen signals activate convergent ROP2-TOR signaling in Arabidopsis
Diverse nitrogen signals activate convergent ROP2-TOR signaling in Arabidopsis
复制标题
拟南芥中不同的氮信号激活会聚 ROP2-TOR 信号传导
DOI：
10.1016/j.devcel.2021.03.022
复制
发表时间：
2021-05-03
影响因子：
11.8
通讯作者：
Xiong, Yan
中科院分区：
文献类型：
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作者：
Liu, Yanlin;Duan, Xiaoli;Xiong, Yan
进化上保守的雷帕霉素靶（TOR）激酶协调所有真核生物中的细胞和生物体生长。氨基酸（AAs）是哺乳动物TOR激活的关键上游信号，但氮相关营养物质如何调节植物中的TOR信号转导却知之甚少。在这里，我们发现，独立于氮同化，硝酸盐和铵的功能作为主要的氮信号激活TOR在拟南芥叶原基。我们进一步鉴定了总共15种蛋白原性AA也能够激活TOR，并且由植物特异性氮同化（谷氨酰胺）、硫同化（半胱氨酸）和乙醇酸循环（甘氨酸）产生的第一种AA表现出最高的效力。有趣的是，硝酸盐、铵和谷氨酰胺都激活了植物2中的小的GTTR Rho相关蛋白（ROP 2），并且组成型活性ROP 2在氮饥饿条件下恢复TOR激活。我们的研究结果表明，特定的进化适应的氮-TOR信号通路发生在植物谱系中，ROP 2可以整合不同的氮和激素信号，植物TOR激活。
The evolutionarily conserved target-of-rapamycin (TOR) kinase coordinates cellular and organismal growth in all eukaryotes. Amino acids (AAs) are key upstream signals for mammalian TOR activation, but how nitrogen-related nutrients regulate TOR signaling in plants is poorly understood. Here, we discovered that, independent of nitrogen assimilation, nitrate and ammonium function as primary nitrogen signals to activate TOR in the Arabidopsis leaf primordium. We further identified that a total of 15 proteinogenic AAs are also able to activate TOR, and the first AAs generated from plant specific nitrogen assimilation (glutamine), sulfur assimilation (cysteine), and glycolate cycle (glycine), exhibit the highest potency. Interestingly, nitrate, ammonium, and glutamine all activate the small GTPase Rho-related protein from plants 2 (ROP2), and constitutively active ROP2 restores TOR activation under nitrogen-starvation conditions. Our findings suggest that specific evolutionary adaptations of the nitrogen-TOR signaling pathway occurred in plant lineages, and ROP2 can integrate diverse nitrogen and hormone signals for plant TOR activation.