Function and diversification of ESCRT proteins in plant endosomal sorting

该项目将分析细胞如何降解锚定在膜上的蛋白质，以及这一过程如何影响植物发育。 与该项目相关的活动将为本科生、研究生和博士后研究人员提供细胞生物学、生物化学、光学和电子显微镜以及计算生物学方面的培训机会。它还将为科学界提供工具和数据，以了解植物生物学的基本原理和细胞内称为细胞器的结构的功能。与医学工程组和麦迪逊的威斯康星州探索中心的3D打印制造实验室合作，将为麦迪逊地区K-12学生的外联活动制作代表不同细胞器的三维打印。细胞执行基本细胞功能以及彼此相互作用和与环境相互作用的能力依赖于控制其质膜的组成，即暴露于细胞表面的受体、转运蛋白和酶的数量和种类。需要降解的质膜蛋白首先被递送至内体，在内体中被分选至内体内腔囊泡中，用于它们在溶解细胞器（例如溶酶体和液泡）中的降解。虽然对于所有真核细胞的生命都是必不可少的，但内体囊泡如何形成以及它们如何隔离质膜蛋白尚未完全了解。该提案旨在1）通过电子断层扫描和计算机模拟分析植物内体中膜几何形状的先前未表征的特征; 2）表征一种新型蛋白质复合物，其可以介导膜脂质的局部修饰以促进内体成熟; 3）分析内体蛋白质与调节囊泡向质膜递送的机制之间的新型连接的作用。

This project will analyze how cells degrade proteins anchored in membranes and how this process affects plant development. The activities associated with this project will provide training opportunities for undergraduates, a graduate student, and a postdoctoral researcher in cell biology, biochemistry, light and electron microscopy, and computational biology. It will also provide the scientific community with tools and data to understand basic principles of plant biology and the function of structures within cells called organelles. In collaboration with the Medical Engineering Group and the Fabrication Laboratory for 3D printing at the Wisconsin Discovery Center in Madison, three-dimensional prints representing different organelles will be produced for outreach activities with K-12 students in the Madison area. The ability of cells to perform basic cellular functions and to interact with each other and with their environment relies on controlling the composition of their plasma membrane, that is, the number and kind of receptors, transporters, enzymes that are exposed to the cell surface. Plasma membrane proteins that need to be degraded are first delivered to endosomes where are sorted into endosomal lumenal vesicles for their degradation in lytic organelles, such as lysosomes and vacuoles. Although essential for the life of all eukaryotic cells, how endosomal vesicles form and how they sequester plasma membrane proteins is not fully understood. This proposal aims to 1) analyze previously uncharacterized features of the membrane geometry in plant endosomes by electron tomography and computational simulations; 2) characterize a novel protein complex that could mediate local modifications of membrane lipids to contribute to endosomal maturation; 3) analyze the role of a novel connection between endosomal proteins and the machinery that regulates the delivery of vesicles to the plasma membrane.