Connecting plasma membrane function to lipid structure and organization with asym

通过不对称将质膜功能与脂质结构和组织联系起来

• 批准号: 7867819
• 负责人: NOAH MALMSTADT
• 金额: $ 28.87万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-30 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7867819
• 关键词: Affect; Automobile Driving; Basic Science; Behavior; Binding; Biochemistry; Biological; Biological Process; Biotechnology; Carbohydrates; Cell membrane; Cells; Cellular Morphology; Cellular Structures; Charge; Chemicals; Cilia; Complex; Crowding; Cytoplasm; DNA-Protein Interaction; Data; Development; Diabetes Mellitus; Disease; Drug Delivery Systems; Drug Transport; Extracellular Space; Fluorescence; Fluorescence Microscopy; Gene Expression; Genetic Transcription; Health; Human; Individual; Integral Membrane Protein; Ions; Lipid Bilayers; Lipids; Location; Measures; Mechanics; Membrane; Membrane Proteins; Microfluidics; Modeling; Molecular; Molecular Biology; Molecular Medicine; Molecular Structure; Monitor; Oligonucleotides; Peptides; Pharmaceutical Preparations; Phosphatidylserines; Physiological Processes; Play; Process; Property; Proteins; Research; Resistance; Role; Route; Signal Transduction; Site; Structure; Structure-Activity Relationship; System; Techniques; Testing; Toxic Environmental Substances; Translations; Transmembrane Domain; Vesicle; Viral; Virus; annexin A5; base; cancer therapy; cell behavior; design; interest; lipid structure; molecular asymmetry; nucleic acid structure; particle; passive transport; protein function; public health relevance; receptor; research study; scaffold; small molecule; solute; tool

DESCRIPTION (provided by applicant): Over the past half century, as molecular biology and biochemistry have developed to inform our understanding of disease, and as this understanding has driven the search for treatments in biotechnology and molecular medicine, the dominant theoretical scaffold for interpreting molecular behavior has been the structure-function relationship. Our understanding of molecular biology's structure-function relationships is largely limited, however, to the molecules of the central dogma: proteins and oligonucleotides. The vast variety of molecular structure outside of the central dogma, particularly among lipids and carbohydrates, suggests that these, too, can be understood in terms of structure driving function. In particular, there has been intense interest in the functional role that lipids might play in the plasma membrane. This project deploys a new class of synthetic lipid bilayers to begin drawing connections between the structure of lipid molecules-both in terms of individual molecular structure and supermolecular organization-and the function of the plasma membrane. The research tools developed and deployed here, called asymmetric giant unilamellar vesicles (AGUVs), are designed to uniquely mimic the cell membrane, capturing properties such as compositional asymmetry and molecular crowding better than other existing synthetic lipid bilayers. One of the many questions that AGUVs can help answer involves passive transport across the cell membrane. Passive transport is an important route for drug delivery and passage of environmental toxins into cells. Recent results show that the mechanism of this transport is complex, and highly dependent on lipid behavior. This project deploys an AGUV-based technique for systematically measuring the dynamics of solute molecules interacting with and penetrating lipid bilayers, yielding richer mechanistic data than other approaches are capable of delivering. AGUVs can also be used to study the mechanical properties of the cell membrane. These properties- particularly resistance to bending-control protein function and are important in a range of physiological processes. While synthetic lipid bilayers have been used to probe these properties, little is known about the effects of bilayer asymmetry on them. This project uses AGUVs to discover these effects. Lipid interactions with integral membrane proteins are likely a major mode by which lipids influence cell behavior. Very little is known, however, about the origins or controlling parameters of these interactions. This project begins to untangle this problem in AGUVs by using fluorescence microscopy to probe how peptides modeling the transmembrane regions of various proteins associate with segregated lipid domains. Finally, AGUVs can facilitate the systematic study of the effects of macromolecular crowding in the cell interior. The microfluidic technique by which AGUVs are formed allows for the inclusion of arbitrary molecules within them, leading to unique molecularly crowded structures. PUBLIC HEALTH RELEVANCE: Cells are surrounded by membranes that consist of two layers of lipid molecules, and the chemical composition is different in these two layers. In this project, a new type of artificial cell membrane that is uniquely capable of mimicking this asymmetry is deployed to study a range of important biological processes, including drug transport into cells, mechanical deformation of the cell membrane, and interactions between lipid molecules and receptor proteins involved in cancer treatment and diabetes.

描述(申请人提供)：在过去的半个世纪里，随着分子生物学和生物化学的发展，我们对疾病的理解，以及这种理解推动了生物技术和分子医学中治疗方法的探索，解释分子行为的主要理论框架一直是结构-功能关系。然而，我们对分子生物学的结构-功能关系的理解在很大程度上局限于中心教条的分子：蛋白质和寡核苷酸。中心法则之外的各种分子结构，特别是脂类和碳水化合物之间的分子结构，表明这些也可以从结构驱动功能的角度来理解。特别是，人们对脂类在质膜中可能扮演的功能角色产生了浓厚的兴趣。该项目部署了一类新的合成脂质双层，以开始绘制脂质分子结构--包括单个分子结构和超分子组织--与质膜功能之间的联系。这里开发和部署的研究工具称为不对称巨型单层囊泡(AGUV)，旨在独特地模拟细胞膜，比其他现有的合成脂质双层更好地捕捉组成不对称和分子拥挤等特性。AGUV可以帮助回答的许多问题之一是关于细胞膜的被动运输。被动转运是药物输送和环境毒素进入细胞的重要途径。最近的研究结果表明，这种转运的机制是复杂的，并且高度依赖于脂质行为。该项目部署了一种基于AGUV的技术，用于系统地测量溶质分子与脂质双层相互作用和穿透的动力学，产生比其他方法能够提供的更丰富的机械数据。AGUV还可以用来研究细胞膜的机械性能。这些特性--尤其是抗弯曲控制蛋白质的功能，在一系列生理过程中都很重要。虽然人工合成的脂质双分子层已经被用来探索这些性质，但对双分子层不对称对它们的影响知之甚少。该项目使用AGUV来发现这些效果。脂类与完整膜蛋白的相互作用可能是脂类影响细胞行为的主要方式。然而，人们对这些相互作用的起源或控制参数知之甚少。这个项目开始解开AGUV中的这个问题，使用荧光显微镜来探索模拟各种蛋白质的跨膜区的多肽如何与分离的脂类结构域相关联。最后，AGUV可以促进对细胞内部大分子拥挤效应的系统研究。形成AGUV的微流控技术允许在其中包含任意分子，导致独特的分子拥挤结构。 与公共卫生相关：细胞被由两层脂分子组成的膜所包围，这两层中的化学成分不同。在这个项目中，一种新型的人造细胞膜被用来研究一系列重要的生物过程，包括药物进入细胞的运输，细胞膜的机械变形，以及参与癌症治疗和糖尿病的脂质分子和受体蛋白之间的相互作用。