Stress-induced regulation of N-terminal acetylation controls proteostasis in plants

应激诱导的 N 末端乙酰化调节控制植物中的蛋白质稳态

• 批准号: 496871662
• 负责人: Professor Dr. Rüdiger Hell
• 金额: --
• 依托单位: Centre for Organismal Studies (COS)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/496871662?language=en
• 关键词: Stress; induced; regulation; terminal; acetylation

Growth of plants is limited by environmental factors and corresponding cellular surveillance mechanisms for stress-induced damage repair. The control of protein homeostasis is a major player in the acclimation of the proteome to specific stresses and the replacement of damaged proteins. In this project, the role of the co-translational modification of proteins by N-acetyltransferase (Nat) complexes for acclimation to stress will be investigated. N-terminal acetylation by the major NatA complex affects about 40% of all cytosolic proteins in Arabidopsis with significant effects on their half-life time. Based on the observation that the drought stress hormone abscisic acid (ABA) decreases NatA activity in Arabidopsis, causing faster translation and more efficient degradation of non-acetylated NatA substrates by a novel nonAc/N-degron, we propose that lowered N-terminal acetylation serves as a signal enabling efficient replacement of stress-damaged proteins This novel protein-imprinted stress-transducing signal may generally operate in protein-damaging stress responses. Using drought stress as a proxy, we will dissect the roles of the core and regulatory subunits of the NatA complex for stress-induced protein imprinting at the ribosome. ABA-induced down-regulation of NatA activity will be applied to identify stress-regulated NatA substrates and study the dynamic recruitment of the NatA complex to the ribosome nascent chain complex using selective ribosome profiling. The turnover of ABA-triggered nonAc/N-degron containing proteins can be quantified by in vivo imaging using the tandem fluorescent timer system. The fate of nonAc/N-degron containing proteins is going to be dissected with respect to ubiquitin-proteasome and autophagy-mediated degradation following affinity-based enrichment and protein mass spectrometry. Finally, the role of the sensor kinase TOR for enhanced translation in situations with lowered NatA activity will be assessed. The proposed experiments are expected to clarify the significance and mechanism of action of dynamic N-terminal acetylation for proteostasis under protein-damaging stress.

植物的生长受环境因素和相应的细胞监测机制的限制，用于应激诱导的损伤修复。蛋白质稳态的控制是蛋白质组适应特定胁迫和替代受损蛋白质的主要参与者。在该项目中，将研究通过N-乙酰基转移酶（NAT）复合物对蛋白质的共同修饰的作用，以适应压力。主要NATA复合物的N末端乙酰化影响拟南芥中所有胞质蛋白的40％，对它们的半衰期时间产生重大影响。基于观察结果，即干旱应激激素脱甲酸（ABA）降低了拟南芥的NATA活性，导致更快的翻译和更有效的非乙酰化NATA底物的降解，我们提出降低N-N-Degron作为一种信号，可以有效替换应激损伤的蛋白质这种新型的蛋白质压缩应激转换信号通常可能在蛋白质受损的应激反应中起作用。使用干旱应力作为代理，我们将剖析NATA复合物的核心和调节亚基的作用，以在核糖体处于应激诱导的蛋白质上。 ABA诱导的NATA活性下调将用于鉴定应力调节的NATA底物，并使用选择性核糖体分析研究NATA复合物向核糖体偏离链复合物的动态募集。可以使用串联荧光定时系统的体内成像来量化含有ABA触发的非AC/N-degron含有蛋白质的非ABA触发的蛋白质的营业额。在基于亲和力的富集和蛋白质质谱法之后，含有非AC/N-degron蛋白的命运将相对于泛素 - 蛋白酶体和自噬介导的降解。最后，将评估传感器激酶TOR在NATA活性降低的情况下增强翻译的作用。预计该提出的实验将阐明动态N末端乙酰化对蛋白质损伤应激下蛋白质的作用的重要性和机制。