Phosphorylation events controlling low oxygen-signaling in Arabidopsis thaliana

拟南芥中控制低氧信号的磷酸化事件

• 批准号: 387214090
• 负责人: Professor Dr. Joost T. van Dongen
• 金额: --
• 依托单位: AG van Dongen (Molekulare Ökologie der Rhizosphäre)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/387214090?language=en
• 关键词: Phosphorylation; events; controlling; low; oxygen

Plants exposed to low oxygen conditions, e.g. caused by flooding, show extensive reprogramming of their metabolism. First of all, aerobic respiration (using molecular oxygen) switches to anaerobic metabolism, which still ensures the production of energy equivalents in the form of ATP but with less efficiency. The induction of genes specific to hypoxic adaptation is under the control of transcription factors of the ETHYLENE RESPONSE FACTOR (ERF) family, of which group VII ERFs play a crucial role in this process. Their function is restricted to hypoxia by their oxygen-dependent dissociation from plasma membrane-localized ACYL-COA-BINDING PROTEINS (ACBPs) and subsequent translocation to the nucleus.We already demonstrated that acyl-CoAs, activated fatty acids, trigger translocation of ERFVIIs and showed that certain changes in the cellular acyl-CoA pool induce hypoxic responses. However, because hypoxia-induced changes of the acyl-CoA pool take up to three hours to occur, and acyl-CoA application can induce only mild responses in air as compared to gene induction observed under hypoxia, a second, parallel trigger operating independently of acyl-CoAs is essential for inducing translocation of ERFVIIs and modulating ERFVII activity.The aim of this proposal is to unravel the role of phosphorylation in (1) inducing translocation of ERFVIIs into the nucleus and (2) modulating activity of ERFVIIs in an oxygen-dependent manner. By exploring the impact of phosphorylation in ERFVII-dependent hypoxia signaling we will greatly extend our understanding of the integration of multiple signals under hypoxia with ACBP and ERFVIIs being the central interface.Our preliminary work using in vitro kinase activity assays, in vivo interaction studies, in planta phosphoproteomic analyses and transactivation assays indicates that phosphorylation of components of the ERFVII-dependent signaling cascade is important for both processes. Furthermore, we showed that low oxygen promotes phosphorylation of ACBPs in planta and could identify specific low oxygen-activated MITOGEN-ACTIVATED PROTEIN KINASES (MPKs), which target several components of the ERFVII signaling cascade. We intend to investigate how exactly the phosphorylation status of the signaling components impacts on their ability to interact, their activity and their contribution to low oxygen tolerance in planta. In addition, we want to study under which oxygen concentrations phosphorylation via MPKs occurs in planta. As these MPKs themselves are activated by reactive oxygen species (ROS) under low oxygen, we will investigate to which extend intracellular ROS sources contribute to the induction of the ERFVII signaling cascade. To this aim, we will conduct molecular biological, biochemical as well as genetic strategies.

暴露于低氧条件下的植物，例如由洪水引起的植物，表现出其代谢的广泛重编程。首先，有氧呼吸（使用分子氧）切换到无氧代谢，这仍然确保以ATP形式产生能量当量，但效率较低。低氧适应特异性基因的诱导受乙烯反应因子（ERF）家族转录因子的控制，其中第VII组ERF在此过程中起关键作用。它们的功能仅限于缺氧，这是通过它们与质膜定位的酰基辅酶A结合蛋白（ACBPs）的氧依赖性解离和随后的易位到核中来实现的。我们已经证明，酰基辅酶A（活化的脂肪酸）触发ERFVII的易位，并表明细胞酰基辅酶A库的某些变化诱导缺氧反应。然而，由于缺氧诱导的酰基辅酶A库的变化需要长达三个小时才能发生，并且与缺氧下观察到的基因诱导相比，酰基辅酶A应用在空气中只能诱导轻微的反应，独立于酰基辅酶A的平行触发剂对于诱导ERFVII易位和调节ERFVII活性是必不可少的。诱导ERFVIIs易位到细胞核中和（2）以氧依赖性方式调节ERFVIIs的活性。通过探索ERFVII依赖的缺氧信号中磷酸化的影响，我们将极大地扩展我们对缺氧下多种信号整合的理解，ACBP和ERFVII是中心界面。在植物中磷酸化蛋白质组学分析和反式激活试验表明ERFVII-依赖性信号级联对这两个过程都很重要。此外，我们发现低氧促进植物中ACBPs的磷酸化，并且可以鉴定特定的低氧激活的有丝分裂原激活蛋白激酶（MPKs），其靶向ERFVII信号级联的几个组分。我们打算研究如何确切的磷酸化状态的信号组件的影响，他们的相互作用的能力，他们的活动和他们的贡献，在植物耐低氧。此外，我们想研究在什么样的氧浓度下，通过MPKs磷酸化在植物中发生。由于这些MPK本身在低氧条件下被活性氧（ROS）激活，我们将研究细胞内ROS来源在何种程度上有助于诱导ERFVII信号级联反应。为此，我们将进行分子生物学，生物化学以及遗传学策略。