Role of the FEI/ACC pathway in regulating cell wall synthesis

FEI/ACC 通路在调节细胞壁合成中的作用

• 批准号: 1856431
• 负责人: Joseph Kieber
• 金额: $ 81.36万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1856431&HistoricalAwards=false
• 关键词: Role; FEI; ACC; pathway; regulating

Plant cells are surrounded by a semi-rigid wall that is made primarily of chains of sugars. This plant cell wall provides structural support, defines the size and shape of cells, and provides a barrier to infection by pathogens. Plant cell walls are diverse and highly dynamic structures that respond to developmental and environmental cues. The main load-bearing component of plant cell walls is cellulose, which is made at the surface of cells by a large enzyme complex called cellulose synthase. In this project, it will be characterized how plants regulate how much cellulose they make. Prior work uncovered a pathway that controls this process by modulating the movement of the cellulose synthase complex to the cell surface. How this pathway works and how it interacts with the other elements in the cell to control cellulose synthase will be explored. Further, a novel signaling molecule, 1-aminocyclopropane-1-carboxylic acid (ACC), a precursor to ethylene, was found to act in this pathway. How ACC is perceived by cells and how it acts to modulate cellulose synthase function will be determined. The results from this work will provide insight into how plants regulate cell wall biosynthesis, which is crucial to understanding the development of plant form and other processes and is important for the burgeoning biofuels industry. This project will interact with programs designed to increase the representation of minorities in the sciences and several outreach programs that aim to increase the public understanding of plant science.A signaling pathway regulating cell wall synthesis has been defined that includes the FEI receptor-like kinases, SHOU4 (a novel transmembrane protein), and ACC acting as a signal independent of its conversion to ethylene. Prior results suggest that this pathway regulates CESA (cellulose synthase) function by modulating CESA trafficking to the plasma membrane. A diverse set of complementary experiments are proposed to further elucidate how this pathway regulates CESA function. A primary hypothesis that will be tested is that SHOU4 acts as a counter of CESA levels at the PM, with the complex generating a signal to negatively regulate CESA exocytosis to maintain optimal levels of cellulose biosynthesis. One key aspect of this model is the direct interaction of SHOU4 and CESA. This interaction will be further characterized, including elucidating the role of phosphorylation, potentially by the FEI kinases. Outputs of this complex will be identified by screening for proteins that interact with SHOU4. A second hypothesis that will be tested is that ACC negatively regulates CESA function. A genetic screen was used to identify elements involved in ACC perception. These mutant lines will be further characterized and the genes corresponding to these mutations will be cloned and characterized. These studies will increase the understanding of how cell wall biosynthesis is regulated, a process that is central to many aspects of plant growth and development and which is important for the burgeoning biofuels industry. Further, these studies will begin to define the mechanisms underlying ACC function in plants.This award was co-funded by the Physiological Mechanisms and Biomechanics Program in the Division of Integrative Organismal Systems and the Cellular Dynamics and Function Cluster in the Division of Molecular and Cellular Biosciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

植物细胞被主要由糖链组成的半刚性壁包围。这种植物细胞壁提供结构支撑，限定细胞的大小和形状，并提供病原体感染的屏障。植物细胞壁是一种高度动态的结构，对发育和环境信号做出反应。植物细胞壁的主要承重成分是纤维素，它是由一种叫做纤维素合成酶的大型酶复合物在细胞表面产生的。在这个项目中，它将表征植物如何调节它们制造多少纤维素。先前的工作揭示了通过调节纤维素合成酶复合物向细胞表面的运动来控制这一过程的途径。这一途径如何工作，以及它如何与细胞中的其他元素相互作用，以控制纤维素合成酶将被探索。此外，一种新的信号分子，1-氨基环丙烷-1-羧酸（ACC），乙烯的前体，被发现在这一途径中发挥作用。ACC如何被细胞感知以及它如何调节纤维素合酶功能将被确定。这项工作的结果将为植物如何调节细胞壁生物合成提供深入了解，这对于理解植物形态和其他过程的发展至关重要，对于新兴的生物燃料行业也很重要。该项目将与旨在增加少数民族在科学领域的代表性的项目以及旨在增加公众对植物科学的理解的几个外展项目进行互动。已经定义了调节细胞壁合成的信号通路，包括FEI受体样激酶、SHOU 4（一种新型跨膜蛋白）和ACC作为独立于其转化为乙烯的信号。先前的结果表明，该途径通过调节CESA运输到质膜来调节CESA（纤维素合酶）功能。提出了一套不同的互补实验，以进一步阐明这一途径如何调节CESA功能。将要测试的主要假设是SHOU 4充当PM处CESA水平的计数器，其中复合物产生信号以负调节CESA胞吐作用以维持纤维素生物合成的最佳水平。该模型的一个关键方面是SHOU 4和CESA的直接相互作用。这种相互作用将进一步表征，包括阐明磷酸化的作用，可能是由FEI激酶。该复合物的输出将通过筛选与SHOU 4相互作用的蛋白质来鉴定。将被测试的第二个假设是ACC负调节CESA功能。遗传筛选被用来识别ACC感知所涉及的元素。将进一步表征这些突变株系，并克隆和表征对应于这些突变的基因。这些研究将增加对细胞壁生物合成如何调节的理解，这一过程对植物生长和发育的许多方面都至关重要，对新兴的生物燃料行业也很重要。此外，本发明还这些研究将开始确定ACC在植物中功能的潜在机制。该奖项由综合有机系统部的生理机制和生物力学计划以及分子和细胞生物科学部的细胞动力学和功能组资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值进行评估而被认为值得支持和更广泛的影响审查标准。

项目成果

EXO70D isoforms mediate selective autophagic degradation of type-A ARR proteins to regulate cytokinin sensitivity

• DOI: 10.1073/pnas.2013161117
• 发表时间: 2020-10-27
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Acheampong, Atiako Kwame;Shanks, Carly;Kieber, Joseph J.
• 通讯作者: Kieber, Joseph J.

Mutagenomics: A Rapid, High-Throughput Method to Identify Causative Mutations from a Genetic Screen

• DOI: 10.1104/pp.20.00609
• 发表时间: 2020-12-01
• 期刊: PLANT PHYSIOLOGY
• 影响因子: 7.4
• 作者: Hodgens, Charles;Chang, Nicole;Kieber, Joseph J.
• 通讯作者: Kieber, Joseph J.