Mechanisms of Interleaflet Coupling in Asymmetric Lipid Membranes

不对称脂质膜中的叶间偶联机制

• 批准号: 1817929
• 负责人: Frederick Heberle
• 金额: $ 74.96万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1817929&HistoricalAwards=false
• 关键词: Mechanisms; Interleaflet; Coupling; Asymmetric; Lipid

Living cells communicate with the outside world through a thin double layer of lipids and associated proteins called the plasma membrane. A remarkable feature of this membrane is that its two halves are chemically distinct: the lipids that face the internal contents of the cell are very different from the lipids that face the external environment. It is not clear what role this compositional asymmetry plays in the life of a healthy cell, yet it is clear that cells do not function properly without it, and indeed they expend valuable energy to actively maintain it. This project aims to shed light on the mystery of cell membrane asymmetry by answering the basic question of how the two halves of a membrane communicate with and influence each other. This will be accomplished through the systematic study of how the different types of lipids that are found on each side of an asymmetric membrane influence the properties of the other half, as well as the properties of the membrane as a whole. Because much of a membrane's functionality is derived from the proteins it hosts, the researchers will also investigate how a membrane-resident protein affects, and is in turn affected by lipid asymmetry. In the course of this project, the principle investigator will train graduate students and postdoctoral researchers in experimental and computational methods that will prepare them for careers in STEM fields. The researchers will communicate their findings to the scientific community through conference presentations and peer-reviewed publications and will also engage the public through an outreach program to enhance awareness of and appreciation for biophysical research.Compositional asymmetry of the two bilayer leaflets is a fundamental property of most cellular membranes, including the plasma membrane that surrounds the cell. Although this asymmetry is essential for cell viability, its role in normal cellular function is poorly understood. This project will elucidate the rules that govern communication between the two halves of asymmetric model membranes, leading to improved predictions of functional phenotypes based on the asymmetric lipid composition of a membrane. A primary goal of the project is the use of neutron scattering techniques to reveal how the structural and dynamical properties of each leaflet respond to changes in lipid composition, and to integrate the experimental results with atomistic simulations to inform on the underlying molecular mechanisms responsible for these changes. A second objective is to develop a deeper understanding of how asymmetric membranes adapt to the presence of a transmembrane protein, and how the protein responds in turn to an asymmetric lipid environment. While lipids provide the basic structure of biomembranes, proteins provide most of the functionality; this project will provide much needed information about protein-lipid interactions in the biologically relevant context of an asymmetric membrane. A third objective is the continued development of robust techniques for preparing and characterizing complex asymmetric vesicles for use as advanced plasma membrane model systems.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.

活细胞通过一层叫做质膜的薄薄的双层脂类和相关蛋白质与外界交流。这种膜的一个显著特征是，它的两半在化学上是截然不同的：面对细胞内部内容物的脂类与面对外部环境的脂类非常不同。目前尚不清楚这种成分不对称在健康细胞的生命中扮演着什么角色，但很明显，没有它，细胞就不能正常运作，实际上，它们会花费宝贵的能量来积极地维持它。这个项目旨在通过回答膜的两半如何相互沟通和影响这一基本问题来揭示细胞膜不对称的奥秘。这将通过系统地研究在不对称膜两侧发现的不同类型的脂类如何影响另一半的性质以及膜的整体性质来实现。由于膜的大部分功能来自于它所承载的蛋白质，研究人员还将研究膜驻留蛋白质是如何影响的，进而受到脂质不对称的影响。在这个项目的过程中，首席研究员将对研究生和博士后研究人员进行实验和计算方法方面的培训，为他们在STEM领域的职业生涯做好准备。研究人员将通过会议报告和同行评议出版物向科学界传达他们的发现，还将通过一个外联计划让公众参与进来，以提高对生物物理研究的认识和欣赏。两个双层小叶的成分不对称是大多数细胞膜的基本属性，包括细胞周围的质膜。尽管这种不对称性对细胞活力至关重要，但对其在正常细胞功能中的作用却知之甚少。该项目将阐明控制不对称模型膜两半之间的通信的规则，从而改进基于膜的不对称脂质组成的功能表型的预测。该项目的一个主要目标是使用中子散射技术来揭示每个小叶的结构和动力学性质如何对脂质成分的变化做出反应，并将实验结果与原子模拟相结合，以了解导致这些变化的潜在分子机制。第二个目标是更深入地了解不对称膜如何适应跨膜蛋白的存在，以及蛋白质如何反过来对不对称脂质环境做出反应。虽然脂质提供了生物膜的基本结构，但蛋白质提供了大部分功能；该项目将在不对称膜的生物相关背景下提供关于蛋白质-脂质相互作用的迫切需要的信息。第三个目标是继续开发稳健的技术，用于制备和表征复杂的不对称囊泡，用作先进的质膜模型系统。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Visualizing lipid membrane structure with cryo-EM: past, present, and future

使用冷冻电镜可视化脂质膜结构：过去、现在和未来

• DOI: 10.1042/etls20220090
• 发表时间: 2023
• 期刊: Emerging Topics in Life Sciences
• 影响因子: 3.8
• 作者: Sharma, Karan D.;Heberle, Frederick A.;Waxham, M. Neal
• 通讯作者: Waxham, M. Neal

Peptide-Induced Lipid Flip-Flop in Asymmetric Liposomes Measured by Small Angle Neutron Scattering

• DOI: 10.1021/acs.langmuir.9b01625
• 发表时间: 2019-09-10
• 期刊: LANGMUIR
• 影响因子: 3.9
• 作者: Nguyen, Michael H. L.;DiPasquale, Mitchell;Marquardt, Drew
• 通讯作者: Marquardt, Drew

Influence of ceramide on lipid domain stability studied with small-angle neutron scattering: The role of acyl chain length and unsaturation.

• DOI: 10.1016/j.chemphyslip.2022.105205
• 发表时间: 2022-07
• 期刊: CHEMISTRY AND PHYSICS OF LIPIDS
• 影响因子: 3.4
• 作者: DiPasquale, Mitchell;Deering, Tye G.;Desai, Dhimant;Sharma, Arun K.;Amin, Shantu;Fox, Todd E.;Kester, Mark;Katsaras, John;Marquardt, Drew;Heberle, Frederick A.
• 通讯作者: Heberle, Frederick A.

Building Asymmetric Lipid Bilayers for Molecular Dynamics Simulations: What Methods Exist and How to Choose One?

• DOI: 10.3390/membranes13070629
• 发表时间: 2023-06-29
• 期刊: Membranes
• 影响因子: 4.2

Vesicle Viewer: Online visualization and analysis of small-angle scattering from lipid vesicles

囊泡查看器：脂质囊泡小角度散射的在线可视化和分析

• DOI: 10.1016/j.bpj.2021.09.018
• 发表时间: 2021
• 期刊: Biophysical Journal
• 影响因子: 3.4
• 作者: Lewis-Laurent, Aislyn;Doktorova, Milka;Heberle, Frederick A.;Marquardt, Drew
• 通讯作者: Marquardt, Drew