STRUCTURE AND FUNCTION OF LENS COMMUNICATING CHANNELS

镜头通信通道的结构和功能

• 批准号: 2710845
• 负责人: GUIDO A ZAMPIGHI
• 金额: $ 21.49万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 1982
• 资助国家: 美国
• 起止时间: 1982-08-01 至 1999-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2710845
• 关键词: SDS polyacrylamide gel electrophoresis; X ray crystallography; biological information processing; cell cell interaction; electron microscopy; freeze etching; gap junctions; gel filtration chromatography; image processing; immunocytochemistry; ion exchange chromatography; laboratory rat; lens; lens proteins; membrane channels; membrane permeability; membrane reconstitution /synthesis; monoclonal antibody; pinocytosis; protein reconstitution; protein structure function; western blottings

Eye lens transparency depends to a great extent on the vectorial transport of metabolites, waste products and water between the anterior and posterior lens surfaces. Fiber cells, the principal component of mammalian lens, impose unique demands upon transport; they lack tight junctions, the structures that regulate transport through the extracellular clefts, and contain only small concentrations of Na,K- ATPase, the enzyme that maintains the cell's resting potential by moving Na+ and K+ against their electrochemical gradients. The principal aim of this application is to study the structure and function of the channel for communication between fiber cells in calf lenses (the cell-to-cell channel). The channels form a pathway which is principally responsible for the diffusion of metabolites, waste products and water throughout fiber cells. The application proposes to purify the fiber cell-to-cell channels from bovine calf lenses using non-ionic detergents and column chromatography methods. Experiments are proposed to determine whether fiber cell-to-cell channels are assembled from one connexin (homotypic) or two (i.e., a "mixed" channel). Purified cell-to-cell channels will be crystallized in two-dimensional sheets and their structure studied by cryo-electron microscopy and computer image processing. The purified channels also will be reconstituted in planar lipid bilayers and characterized electrically at the single and multichannel levels. Another aim of the application is to study the pathways of specialized regions of the lens called sutures which are formed by the interaction of fiber cells from opposite regions of the lens. These sutures are important in maintaining lens transparency because their extracellular clefts constitute a direct pathway into the lens interior. Sutures also contain large number of membranous vesicles and tubules which may function in the transport of molecules into fiber cells via a pinocytotic mechanism. The proposed studies of the structure and function of fiber cell-to-cell channels and sutures will be important for the understanding of the mechanisms involved in the maintenance of lens transparency and in the formation of cataracts, the principal disease of the lens.

眼镜透镜透明度在很大程度上取决于矢量运输 前后的代谢物，废物和水 后镜头表面。 纤维细胞，是 哺乳动物的镜头对运输施加了独特的需求；他们缺乏紧身 连接，调节通过运输的结构 细胞外裂缝，仅包含少量的Na，K- ATPase，通过移动来维持细胞静止电位的酶 Na+和K+针对其电化学梯度。主要目的 该应用是研究通道的结构和功能 小腿透镜中的纤维细胞之间的通信（细胞到细胞细胞 渠道）。渠道形成了一条主要负责的途径 整个纤维的代谢物，废物和水的扩散 细胞。该应用程序建议净化纤维细胞到细胞通道 使用非离子洗涤剂和色谱柱从牛小牛镜头 色谱法。提出了实验来确定是否 纤维细胞到细胞通道是从一个连接素（同型）或 两个（即“混合”通道）。纯化的单元间通道将是 用二维床单结晶，其结构由 冷冻电子显微镜和计算机图像处理。纯化 渠道还将在平面脂质双层和 在单一和多通道水平上进行电特征。 该应用程序的另一个目的是研究专业的途径 透镜的区域称为缝合线，由相互作用形成 镜头相对区域的纤维细胞。 这些缝合线是 对于保持晶状体透明度很重要，因为它们的细胞外 裂口构成了进入镜头内部的直接途径。 也是缝合线 包含大量可能起作用的膜囊泡和小管 在分子通过皮细胞传输到纤维细胞中 机制。提出的对纤维结构和功能的研究 细胞间通道和缝合线对于理解很重要 维持晶状体透明度和中涉及的机制 白内障的形成，镜头的主要疾病。