Function Tetraspanins and Tetraspanin-like Proteins in Plant Signaling

四跨膜蛋白和四跨膜蛋白样蛋白在植物信号转导中的功能

• 批准号: 1457123
• 负责人: Marisa Otegui
• 金额: $ 60万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-15 至 2020-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457123&HistoricalAwards=false
• 关键词: Function; Tetraspanins; Tetraspanin; like; Proteins

This project is aimed at understanding how signaling molecules that coexist at the cell surface find each other to mediate cellular responses. Key proteins at the cell surface need to be able to transiently interact with each other when they encounter specific stimuli to trigger a response within the cell. How do the signaling partners find each other in a sea of membrane lipids? A mechanism that cells use to confine membrane proteins to specific domains in a continuous membrane is the expression of proteins that are able to establish protein networks or webs. Tetraspanins are evolutionarily-conserved proteins that facilitate the formation of protein networks and establish signaling modules involved in intercellular communication, cell proliferation, development, and specific responses to biotic and abiotic stimuli. However, there is very little experimental data on their exact molecular mechanisms and what physiological roles they play in plants. This project will analyze the function of tetraspanin and tetraspanin-like proteins in the model plant Arabidopsis thaliana to understand their molecular and physiological roles in vascular development, cell proliferation, and responses to phytohormones. The researcher and her group have identified a plant-specific protein family that shares key structural and functional similarities with tetraspanins. In Arabidopsis thaliana, one member of this family named VASCULAR COMPLEXITY AND CONECTIVITY (VCC) controls vascular development. VCC interacts with TETRASPANIN 1 (TET1) and other signaling molecules involved in vasculature development and localizes to the plasma membrane. The researcher proposes that tetraspanins, VCC proteins, and likely other membrane associated proteins act in a combinatorial manner to establish protein-network modules that contain different associations of receptors and signaling components specific to different plant cell types/tissues. In this context, the evolution of plant tetraspanin-like proteins like the VCC family could have potentially increased the diversity and specificity of protein signaling modules on membranes. This project will analyze two plant tetraspanin signaling modules involved in very different processes. One module is at the plasma membrane, consists of TET1, VCC, and the membrane-associated protein OCTOPUS (OPS), and positively regulates vascular differentiation in Arabidopsis embryos. The other module localizes to the endoplasmic reticulum, contains TET6, and controls seed longevity, seed responses to abscisic acid and oxidative stress during germination. The goals are to identify what other structuring components (other tetraspanins, VCC, or other TET-like proteins) and signaling molecules (e.g. receptors) are part of these signaling modules, to determine what signaling/physiological events they control, and to explore the function and composition of other tetraspanins and VCC protein networks in Arabidopsis though genetic, proteomic, and molecular approaches. This project will provide interdisciplinary training to a postdoctoral fellow, a graduate student, and several undergraduate researchers enrolled in UW-Madison or attending its summer REU program through the Integrated Biological Sciences Summer Research Program. The proposed research will also impact classroom education at the University of Wisconsin. The Principal Investigator teaches three hands-on undergraduate and graduate courses that require the completion of a research project in plant biology. In addition, thirty students taking the Introduction to Engineering Design course at the UW-Madison campus, will interact with the research team on this poroject and design a device specially optimized to facilitate the imaging of plant membrane proteins in intact Arabidopsis embryos and seedlings under controlled environmental conditions.

该项目旨在了解共存于细胞表面的信号分子是如何找到彼此来调节细胞反应的。细胞表面的关键蛋白质需要能够在遇到特定刺激时瞬间相互作用，以触发细胞内的反应。信号伙伴如何在膜脂的海洋中找到彼此？细胞用来将膜蛋白限制在连续膜中特定区域的一种机制是表达能够建立蛋白质网络或网络的蛋白质。Tetraspanins是进化上保守的蛋白质，它促进蛋白质网络的形成，并建立信号模块，参与细胞间通信、细胞增殖、发育和对生物和非生物刺激的特定反应。然而，关于它们的确切分子机制以及它们在植物中所起的生理作用的实验数据很少。本项目将分析Tetraspanin和Tetraspanin样蛋白在模式植物拟南芥中的功能，以了解它们在维管发育、细胞增殖和对植物激素的反应中的分子和生理作用。这位研究人员和她的团队已经确定了一个植物特有的蛋白质家族，该家族在结构和功能上与Tetraspanins有关键的相似之处。在拟南芥中，这个名为VCC的家族成员控制着维管的发育。VCC与TETRASPANIN1(TET1)和其他参与血管发育的信号分子相互作用，并定位于质膜。研究人员提出，Tetraspanins、VCC蛋白和可能的其他膜相关蛋白以组合的方式作用于建立蛋白质网络模块，这些模块包含不同植物细胞类型/组织特有的受体和信号组件的不同关联。在这种背景下，像VCC家族这样的植物Tetraspanin样蛋白的进化可能潜在地增加了膜上蛋白质信号模块的多样性和特异性。这个项目将分析两个植物Tetraspanin信号模块，它们涉及非常不同的过程。一个模块位于质膜上，由TET1、VCC和膜相关蛋白Octopus(OPS)组成，正向调节拟南芥胚胎的维管分化。另一个模块定位于内质网，含有TET6，控制种子寿命、种子对脱落酸的反应和萌发过程中的氧化胁迫。我们的目标是确定这些信号模块的其他结构成分(其他Tetaspanins、VCC或其他类似Tet的蛋白)和信号分子(如受体)，确定它们控制哪些信号/生理事件，并通过遗传学、蛋白质组学和分子学方法探索拟南芥中其他Tetraspanins和VCC蛋白网络的功能和组成。该项目将通过综合生物科学暑期研究计划，为一名博士后、一名研究生和几名进入威斯康星大学麦迪逊分校或参加其夏季REU项目的本科生研究员提供跨学科培训。这项拟议的研究还将影响威斯康星大学的课堂教育。首席研究员教授三门实践的本科生和研究生课程，要求完成植物生物学的研究项目。此外，30名在威斯康星大学麦迪逊校区攻读工程设计导论课程的学生将与研究团队就这一项目进行互动，并设计一种专门优化的设备，以便于在受控环境条件下对完整的拟南芥胚胎和幼苗进行植物膜蛋白成像。