Molecular Mechanism of MAPK Phosphorylation-Induced Stabilization of ACC Synthase and Ethylene Production in Plants under Stress

MAPK 磷酸化诱导胁迫下植物 ACC 合酶和乙烯生产稳定的分子机制

• 批准号: 0543109
• 负责人: Shuqun Zhang
• 金额: --
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-15 至 2010-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0543109&HistoricalAwards=false
• 关键词: Molecular; Mechanism; MAPK; Phosphorylation; Induced

Mitogen-activated protein kinase (MAPK) cascades are conserved eukaryotic signaling modules that transduce extracellular stimuli into intracellular responses. Plant MAPKs are implicated in regulating plant growth, development, and responses to environmental stress. However, the underlying mechanisms in plants by which signals are perceived and transduced are unknown. The long-term goal of this project is to elucidate the functions and mechanisms of actions of two plant stress-responsive MAPKs. Recently, the PI found that in response to stress these MAPKs modulate the biosynthesis of ethylene, a plant stress hormone, by influencing the stability of an ethylene biosynthetic enzyme that responds to stress (ACS2/ACS6). The focus of this project is to investigate how the phosphorylation ACS2/ACS6 leads to its stabilization. Three potential mechanisms will be evaluated: i) phosphorylation triggers the binding of a protein that prevents the degradation of phosphorylated ACS2/ACS6; ii) phosphorylation prevents the binding of a protein that targets unphosphorylated ACS2/ACS6 to degradation; and iii) the combination of the above two. This project will impact three major areas of plant research, including i) the molecular mechanism of plant MAPK function, ii) the regulation of plant hormone biosynthesis, and iii) the regulation of ubiquitin-proteasome mediated protein degradation by phosphorylation and dephosphorylation. A combination of biochemical, proteomic, molecular, and genetic approaches will be used, which will provide an excellent training environment for students and post-docs. Training of students and post-docs who can take an integrative approach to study a biological phenomenon is critical to the advance of post-genome biology. In addition, undergraduate students, especially those from under-represented groups, will be actively recruited through institutional programs that reach out to minorities. Ethylene plays important roles in the adaptation of plants to adverse environmental conditions, in addition to its role in regulating growth and development. One potential application of this work is that the identification of important regulatory components in MAPK-mediated ethylene induction pathway may lead to the generation of crops with enhanced stress tolerance, therefore, allowing the use of marginal land for crop production.

丝裂原活化蛋白激酶（MAPK）级联是真核生物中保守的信号转导模块，它将细胞外刺激转化为细胞内反应。植物MAPK参与调节植物生长、发育和对环境胁迫的响应。然而，植物中感知和转导信号的潜在机制尚不清楚。本项目的长期目标是阐明两种植物逆境应答MAPKs的功能和作用机制。 最近，PI发现响应于胁迫，这些MAPK通过影响响应于胁迫的乙烯生物合成酶（ACS 2/ACS 6）的稳定性来调节植物胁迫激素乙烯的生物合成。本项目的重点是研究ACS 2/ACS 6的磷酸化是如何导致其稳定的。 将评价三种潜在机制：i）磷酸化触发蛋白质结合，防止磷酸化的ACS 2/ACS 6降解; ii）磷酸化防止靶向未磷酸化的ACS 2/ACS 6的蛋白质结合降解; iii）上述两种机制的组合。 该项目将影响植物研究的三个主要领域，包括i）植物MAPK功能的分子机制，ii）植物激素生物合成的调节，iii）通过磷酸化和去磷酸化调节泛素-蛋白酶体介导的蛋白质降解。将使用生物化学，蛋白质组学，分子和遗传学方法的组合，这将为学生和博士后提供良好的培训环境。培养能够采取综合方法研究生物现象的学生和博士后对后基因组生物学的发展至关重要。此外，本科生，特别是那些来自代表性不足的群体，将通过机构计划，接触到少数民族积极招募。乙烯除了在调节生长和发育中的作用外，还在植物适应不利环境条件方面发挥重要作用。这项工作的一个潜在应用是，MAPK介导的乙烯诱导途径中的重要调控组分的鉴定可能导致产生具有增强的胁迫耐受性的作物，因此，允许利用边际土地进行作物生产。