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Understanding How Integral Membrane Proteins Influence the Continuum Mechanics of Cell Membranes.

了解完整膜蛋白如何影响细胞膜的连续体力学。

基本信息

批准号：
1915017
负责人：
Noah Malmstadt
金额：
$ 35万
依托单位：
University of Southern California
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-01 至 2022-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1915017&HistoricalAwards=false
关键词：
Understanding How Integral Membrane Proteins

项目摘要

The goal of this proposal is to establish experimental techniques and develop foundational experimental data describing how general integral membrane proteins affect the mechanical properties of biomembranes. These tools and results will have a transformative effect on our understanding of biomembranes as continuum materials. Most contemporary research in bilayer-protein interactions focuses either on how specific proteins (SNARE complexes, viral fusion proteins) exert force on lipid bilayers or how forces in the lipid bilayer can modulate integral membrane protein function. The PI is looking at the membrane as a continuum material in which the mechanical properties are determined by both the lipids and the integral membrane proteins. Given the high concentration of proteins in the membrane, such a view is necessary in order to fully understand how biomembranes move and deform. Membrane deformation is a central phenomenon in biology, underlying such processes as cell division, viral infection, and neurotransmitter release. This proposal includes a comprehensive educational plan for outreach to high school students. The primary objective of this outreach program is to facilitate intensive research experiences for students drawn from the diverse population of the Los Angeles Unified School District. This will be accomplished by cooperating with an established outreach program at the Engineering for Health Academy at Francisco Bravo Medical Magnet High School to bring grade-12 students into the laboratory for yearlong internships. Interns will be mentored by the graduate student funded by this award and will undertake their own small, independent research projects.The PI will use standard methods for measuring the mechanical properties of lipid bilayers in giant unilamellar lipid vesicles (GUVs). The key innovative aspect of this research is enabled by a technology that the PI's laboratory recently developed to incorporate integral membrane proteins into GUVs at relatively high concentrations. This will allow the PI to examine the mechanical properties on GUVs with controlled concentrations of membrane proteins. The PI will investigate proteins with a variety of transmembrane motifs to discover how the structure of the transmembrane domains affects how proteins are mechanically coupled to the bilayer. The two properties that will be measured for each protein at a range of concentrations are: 1.) The tendency of a membrane to bend when no external forces are applied. This is described by the spontaneous (or intrinsic) curvature JSB. 2.) The amount of energy required to bend the membrane away from its intrinsic curvature. This is described by the bending modulus kc. These two parameters are central to describing the energetics of membrane deformation during biological processes. The PI will use a combination of micropipette aspiration and vesicle fluctuation analysis to independently determine the value of each parameter for a given set of conditions.This project is being jointly supported by the Physics of Living Systems program in the Division of Physics and the Molecular Biophysics program 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.

该提案的目标是建立实验技术，并开发基础实验数据，描述一般膜蛋白质如何影响生物膜的机械性能。这些工具和结果将对我们对生物膜作为连续体材料的理解产生变革性影响。大多数当代的研究在双层蛋白质相互作用的重点是如何特定的蛋白质（陷阱复合物，病毒融合蛋白）施加力的脂质双层或如何在脂质双层的力量可以调节完整的膜蛋白功能。PI将膜视为一种连续体材料，其机械性能由脂质和膜蛋白组成。鉴于膜中蛋白质的高浓度，为了充分理解生物膜如何移动和变形，这样的观点是必要的。膜变形是生物学中的一个中心现象，是细胞分裂、病毒感染和神经递质释放等过程的基础。该提案包括一项向高中生推广的综合教育计划。这个外展计划的主要目标是促进密集的研究经验，从洛杉矶联合学区的不同人口的学生。这将通过与弗朗西斯科布拉沃医学磁铁高中健康工程学院的一个既定外联项目合作来实现，将12年级的学生带到实验室进行为期一年的实习。实习生将由该奖项资助的研究生指导，并将开展自己的小型独立研究项目。PI将使用标准方法测量巨单层脂质囊泡（GUV）中脂质双层的机械性能。这项研究的关键创新方面是由PI实验室最近开发的一项技术实现的，该技术将整合膜蛋白以相对高的浓度掺入GUV中。这将允许PI检查具有受控浓度的膜蛋白的GUV的机械性能。PI将研究具有各种跨膜基序的蛋白质，以发现跨膜结构域的结构如何影响蛋白质与双层的机械偶联。将在一定浓度范围内对每种蛋白质测量的两种性质是：1.当没有外力作用时薄膜发生弯曲的趋势。这由自发（或固有）曲率JSB描述。2.）的情况。使膜从其固有曲率弯曲所需的能量。这通过弯曲模量kc来描述。这两个参数是描述生物过程中膜变形的能量学的核心。PI将使用微量吸液管抽吸和囊泡波动分析的组合来独立确定给定条件下每个参数的值。该项目由物理学部的生命系统物理学项目和分子与细胞生物科学部的分子生物物理学项目共同支持。该奖项反映了NSF的法定使命，并被认为值得支持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。