Understanding Highly Heterogeneous Biological Membranes

了解高度异质的生物膜

• 批准号: 2129209
• 负责人: Carlos Baiz
• 金额: $ 75.74万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2129209&HistoricalAwards=false
• 关键词: Understanding; Highly; Heterogeneous; Biological; Membranes

Biological membranes are highly complex environments that play a central role in a wide range of cellular functions such as cell-cell communication and energy production. Membranes contain hundreds of unique lipids organized on a nanometer length scale, and this organization is critical for cellular function. Membranes contain a large number of lipids, which serve specific functions. For example, certain lipid species are present as signaling molecules to regulate certain biochemical processes. Abnormal lipid distributions have been linked to human diseases. The specific biological roles of lipid membrane composition are not fully understood since the tools to investigate membrane architectures are severely limited. Microscopic interactions among the different components, on a molecule-to-molecule basis, determine the microscopic distribution of lipids and local membrane structure. This project will bring forth cutting-edge experimental tools based on time-resolved spectroscopy and single-molecule imaging to investigate the specific environment and the molecular geometries associated with membrane signaling. In addition, the team will develop multiscale simulation methods to obtain an atomistic view of membranes and aid in the interpretation of experiments. Specifically, the project will focus on understanding how certain negatively-charged lipid species can alter the binding affinities of signaling proteins. This collaborative project will provide a platform for training visiting students across research groups and to increase the number of underrepresented students enrolled in the Chemistry and Neuroscience graduate programs at UT-Austin. In this project, the research team will investigate lipid membrane environments and the role of signaling lipids using a combination of biochemical methods, fluorescently-labeled lipids, vibrational spectroscopy, single-molecule microscopy, and enhanced-sampling molecular dynamics simulations. Specifically, the team will focus on harvesting intact plasma membranes from mammalian cell lines that will be imaged using fluorescence microscopy and tip-enhanced infrared spectroscopy. This project seeks to establish a molecular-level view of lipid-lipid and lipid-protein interactions to inform the importance of membrane composition. The following aspects of membranes will be the primary focus of the project: 1. The team will characterize how model transmembrane helices sample a different range of local environments in a mixture with other lipids, with specific emphasis on the sequence of the protein sequence. 2. The team will determine how proteins become partitioned in heterogeneous bilayers using model helical peptides with a well-defined balance between hydrophobic and hydrophilic residues. The team will measure IR spectra of single transmembrane helices embedded in harvested plasma membranes. 3. The team will explore the role of the membrane as a “signaling lipid reservoir” by capturing the interactions between PIP2 signaling lipids and other anionic lipids within the membrane bulk to inform how these interactions drive signaling functions.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.

生物膜是高度复杂的环境，在细胞间通讯和能量产生等多种细胞功能中起着核心作用。膜包含数百种独特的脂质，以纳米长度组织，这种组织对细胞功能至关重要。细胞膜含有大量具有特定功能的脂质。例如，某些脂质物种作为信号分子存在，以调节某些生化过程。异常的脂质分布与人类疾病有关。由于研究膜结构的工具受到严重限制，脂质膜组成的特定生物学作用尚未完全了解。不同组分之间的微观相互作用，在分子到分子的基础上，决定了脂质和局部膜结构的微观分布。该项目将采用基于时间分辨光谱和单分子成像的尖端实验工具来研究与膜信号相关的特定环境和分子几何形状。此外，该团队将开发多尺度模拟方法，以获得膜的原子观，并帮助解释实验。具体来说，该项目将专注于了解某些带负电荷的脂质物种如何改变信号蛋白的结合亲和力。该合作项目将为跨研究小组培训访问学生提供一个平台，并增加在UT-Austin化学和神经科学研究生课程中注册的代表性不足的学生的数量。在这个项目中，研究小组将使用生化方法、荧光标记脂质、振动光谱、单分子显微镜和增强采样分子动力学模拟相结合的方法来研究脂质膜环境和信号脂质的作用。具体来说，该团队将专注于从哺乳动物细胞系中收集完整的质膜，并使用荧光显微镜和尖端增强红外光谱对其进行成像。该项目旨在建立脂质-脂质和脂质-蛋白相互作用的分子水平观点，以告知膜组成的重要性。膜的以下几个方面将是项目的主要重点：1。该团队将描述模型跨膜螺旋如何在与其他脂质的混合物中采样不同范围的局部环境，特别强调蛋白质序列的顺序。2. 该团队将使用具有疏水和亲水残基之间明确平衡的模型螺旋肽来确定蛋白质如何在不均匀双层中分裂。该团队将测量嵌入在收获的质膜中的单个跨膜螺旋的红外光谱。3. 该团队将通过捕获PIP2信号脂质与膜体内其他阴离子脂质之间的相互作用来探索膜作为“信号脂库”的作用，以了解这些相互作用如何驱动信号功能。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。