Posttranslational regulatory modules of carbon partitioning and allocation

植物作为一种无根生物，能够在整个昼夜循环中迅速适应不断变化的碳有效性。因此，将资源分配给涉及膜转运体的生长汇器官与代谢和储存功能紧密结合。这种精确的调节需要对代谢活动和膜运输进行严密和综合的控制。在过去的几年里，已经确定了磷酸化位点及其在中心碳和蔗糖代谢中的蛋白质动力学以及各自的运输，但现有的关于这些修饰在代谢，储存和运输调节中的作用的知识仍然有限。该项目的主要目的是进一步详细了解蛋白质磷酸化在细胞外或细胞内蔗糖可用性波动的背景下的作用。在拟议的实验中，我们将使用具有改变内在蔗糖状态的不同突变体。我们的目标是(i)在不同的外部和内部蔗糖可用性条件下，定量监测具有蔗糖相关反应的关键蛋白的蛋白磷酸化，并将其与蛋白质活性联系起来，（ii）研究不同蔗糖状态下各自突变体中膜蛋白的亚室分布，以及（iii）验证选定的蔗糖相关激酶-底物关系。总的来说，该项目将对植物如何在快速变化的外部条件下利用翻译后调控来综合响应不同的碳利用需求获得新的见解。

Plants as sessile organisms are able to rapidly adapt to altering carbon availability throughout the diurnal cycle. Thereby, allocation of resources to growing sink organs involving membrane transporters is tightly integrated with metabolic and storage functions. This precise regulation requires tight and integrated control of metabolic activities and membrane transport. In the past years, phosphorylation sites and their dynamics of proteins in central carbon and sucrose metabolism as well as for respective transport were identified, but existing knowledge about the role of these modifications in modulation of metabolism, storage and transport is still limited. The major aim of this project is to gain further detailed insights into the role of protein phosphorylation in context of fluctuations in sucrose availability from extracellular or intracellular sources. In the proposed experiments, we will use different mutants with altered intrinsic sucrose status. We aim at (i) quantitatively monitoring protein phosphorylation of key proteins with sucrose-related responses in targeted assays under conditions of different external and internal sucrose availability and relate it to protein activities, (ii) studying subcompartmental distribution of membrane proteins in the respective mutants under different sucrose status, and (iii) verifying selected sucrose-related kinase-substrate relationships. Overall, the project will gain novel insights into on how plants use posttranslational regulation to integratedly respond to different requirements for carbon usage under rapidly changing external conditions.