CAREER: Elucidating the hormonal regulation of cellulose synthase complexes by post-translational phosphorylation

该项目旨在了解植物如何控制纤维素的合成，纤维素是一种至关重要的多糖，控制植物的生长和发育。 纤维素是人类和饲料动物食物、纤维、纺织品和燃料的重要组成部分。 虽然许多参与陆地植物纤维素合成的酶已经被确定，但植物如何决定生产更多或更少的纤维素仍然不清楚。 华莱士实验室将使用先进的遗传，生物化学和细胞生物学技术来阐明纤维素生物合成在正常植物发育过程中是如何控制的，以及如何应对不断变化的环境条件，如高温，干旱，盐胁迫和营养限制。 这一信息将被用来设计纤维素含量增加的植物，这些植物可用作合成可持续增值产品的生物质原料，或用作饲料动物的更有效的原料。 通过了解纤维素生物合成是如何控制的，研究人员还希望为理解植物细胞生物学的这一基本特征如何与植物生长和发育联系起来提供基础。 此外，该项目将支持来自不同和代表性不足背景的研究生，本科生和高中生的研究培训。 该项目还将支持本科生定量质谱模块的课程开发，以及通过当地农业活动和网络视频进行公众宣传。 长期目标是了解植物纤维素生物合成是如何通过翻译后磷酸化来控制的，并利用这些知识在不断变化的环境条件下增加纤维素产量。 指导这项研究工作的中心假设是CESA（纤维素合成酶A）亚基和其他CSC（纤维素合成酶复合物）组分被参与油菜素类固醇信号级联的蛋白激酶磷酸化，这些磷酸化事件调节CSC速度或亚细胞定位。 具体目标1采用生物化学和遗传学方法来确定油菜素类固醇调节蛋白激酶，磷酸化和调节CSC的组成部分，并了解这些调控事件如何控制植物的生长和发育。 具体目标2利用先进的定量蛋白质组学方法来研究如何改变环境条件导致CSC磷酸化的改变。 具体目标3侧重于确定CESA亚基的磷酸化如何影响纤维素生物合成的体外酶活性。 这项工作的统一目标是全面了解翻译后磷酸化如何调节CSC在体外和体内的活性。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

This project seeks to understand how plants control the synthesis of cellulose, a critically important polysaccharide that governs plant growth and development. Cellulose is an important component of food, fiber, textiles, and fuel for human and forage animals. While many of the enzymes that participate in cellulose synthesis in land plants have been identified, it is still unclear how plants make the decision to produce more or less cellulose. The Wallace lab will use advanced genetic, biochemical, and cell biological techniques to elucidate how cellulose biosynthesis is controlled during normal plant development and in response to changing environmental conditions, such as heat, drought, salt stress, and limiting nutrients. This information will be utilized to engineer plants with increased cellulose contents that could be used as biomass feedstocks for the synthesis of sustainable value-added products or as more efficient feedstocks for forage animals. By understanding how cellulose biosynthesis is controlled, the investigator also expects to provide a foundation for understanding how this fundamental feature of plant cell biology is linked to plant growth and development. Additionally, this project will support the research training of graduate, undergraduate, and high school students from diverse and under-represented backgrounds. This project will also support the course development of a quantitative mass spectrometry module for undergraduate students as well as public outreach through local agricultural events and web-based videos. The long-term goal is to understand how plant cellulose biosynthesis is controlled by post-translational phosphorylation, and to utilize this knowledge to increase cellulose output under changing environmental conditions. The central hypothesis guiding this research effort is that CESA (Cellulose synthase A) subunits and other CSC (Cellulose Synthase Complex) components are phosphorylated by protein kinases involved in the brassinosteroid signaling cascade, and these phosphorylation events regulate CSC velocity or subcellular localization. Specific Aim 1 employs biochemical and genetic methods to identify brassinosteroid-regulated protein kinases that phosphorylate and regulate components of the CSC and to understand how these regulatory events control plant growth and development. Specific Aim 2 utilizes advanced quantitative proteomic methods to investigate how changing environmental conditions lead to alterations in CSC phosphorylation. Specific Aim 3 focuses on determining how phosphorylation of CESA subunits influences the in vitro enzymatic activity of cellulose biosynthesis. The unifying goal of this work is to develop a holistic understanding of how post-translational phosphorylation regulates that activity of the CSC both in vitro and in vivo.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.