Mass spectrometric based analysis of plasma membrane proteins that regulate cell expansion in Arabidopsis thaliana.

存在于细胞外膜中的分子就像天线一样感知环境的变化，并通过化学反应（例如磷酸化）和形状（或构象）的变化将这些信息传递到细胞中。新开发的技术允许使用质谱方法检测分子中的这种构象变化，并且在本项目中，这些新技术将用于了解信号如何调节植物细胞大小的快速扩张。将为高中生开发练习，使用质谱分析常见的食物蛋白质，如大豆豆腐。美国公共广播公司（PBS）在威斯康星大学生物技术中心免费播出的电视连续剧《实验室的星期三晚上》（Wednesday night at the Lab）将以植物蛋白质分析为例，向公众解释（并揭开）质谱分析的神秘面纱，并解释这对他们的日常生活有何影响。总的来说，这个项目试图结合体外和体内的方法来理解信号在质膜上传输的分子基础。本项目重点研究植物质膜受体激酶Feronia及其肽激素配体RALF。当RALF结合到Feronia的细胞外结构域时，细胞扩张的速度在几分钟内降低。该项目将开发和应用新的基于质谱的工具来分析细胞外RALF在Feronia诱导的构象变化。新设计的PLIMB仪器（等离子体诱导生物分子修饰）可以产生微秒的羟基自由基脉冲，将用于“足迹”Feronia和其他参与Feronia/RALF作用的蛋白在质膜上。

Molecules present in the outer membranes of cells act as antennae to perceive changes in the environment, and transmit this information into the cell by chemical reactions (for example phosphorylation) and by changes in shape (or conformation.) Newly developed technologies allow such conformational changes in molecules to be detected using the methods of mass spectrometry, and in this project these new technologies will be used to understand how signals regulate the rapid expansion of plant cell size. Exercises will be developed for high school students, using mass spectrometry to analyze common food proteins such as soybean tofu. A PBS television series "Wednesday Nite at the Lab" that is broadcast free from the University of Wisconsin Biotechnology Center will explain to the general public (and demystify) mass spectrometry, using as an example the analysis of plant proteins and explaining how this impacts their everyday lives. Overall this project seeks to combine in vitro and in vivo approaches to understanding the molecular basis for signal transmission across the plasma membrane. The focus of this project is Feronia, a plant plasma membrane receptor kinase, and its peptide hormone ligand, RALF. When RALF binds to the extracellular domain of Feronia, the rate of cell expansion is reduced within minutes. This project will develop and apply novel mass spectrometric based tools for analyzing the conformational changes that extracellular RALF induces in Feronia. The newly devised PLIMB instrument (Plasma Induced Modification of Biomolecules) that generates microsecond pulses of hydroxyl radicals will be used to "footprint" Feronia and other proteins that are involved in Feronia/RALF action at the plasma membrane.