Impact of NRT2.1 posttranslational regulatory mechanisms on nitrate uptake and sensing

硝酸盐是植物生长所必需的大量营养元素。此外，它还具有信号传导功能，触发新陈代谢和根发育中的特定适应。以.在拟南芥中，转运蛋白NRT 2.1已知在根硝酸盐吸收中具有核心作用，并且它还可以在响应于硝酸盐的根发育的信号传导中发挥作用。由两个合作伙伴发起的先前工作开始绘制NRT 2.1翻译后调控的复杂图片，涉及N-和C-末端在总共五个不同位点的磷酸化，与合作伙伴蛋白的相互作用，以及C-末端部分的切割。该项目的目标是建立在德国和法国合作伙伴之间强大的技能互补性的基础上，并将蛋白质组学方法与生物化学，遗传学和植物生理学相结合，以破译这些复杂的调控机制。具体而言，该项目旨在（i）根据其修饰状态了解NRT 2.1的蛋白质-蛋白质相互作用的动力学，（ii）鉴定作用于NRT 2.1的其他调节蛋白（激酶，磷酸酶），（iii）破译NRT 2.1 C-末端蛋白水解作为额外调节机制的机制。该项目将为根系硝酸盐吸收和/或硝酸盐传感的调节提供新的和有价值的见解，这对提高植物氮素利用效率具有战略意义。

Nitrate is an essential macronutrient for plant growth. In addition it has signaling functions triggering specific adaptations in metabolism and root development. In A. thaliana, the transporter NRT2.1 is known to have a central role for root nitrate uptake and it could also play a role in signaling for root development in response to nitrate. Previous work initiated by both partners started to draw a complex picture for NRT2.1 post-translational regulations involving phosphorylation of N- and C-terminus at a total of five different sites, interaction with partner proteins, and cleavage of the C-terminal part. The goal of this project is now to build on the strong complementarity of skills between the German and the French partners and combined proteomics approaches with biochemistry, genetic and plant physiology to decipher these complex regulatory mechanisms. Specifically, the project aims at (i) understanding the dynamics of protein-protein interactions of NRT2.1 depending on its modification status, (ii) identification of further regulatory proteins (kinases, phosphatases) acting on NRT2.1, (iii) deciphering the mechanisms of NRT2.1 C-terminal proteolysis as an additional regulatory mechanism. The project will provide novel and valuable insights into the regulation of root nitrate uptake and/or nitrate sensing, which has a strategic importance to improve plants nitrogen use efficiency.