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.

眼晶状体透明度在很大程度上取决于矢量传输 前部和前部之间的代谢物、废物和水 晶状体后表面。 纤维细胞，主要成分 哺乳动物的晶状体，对运输提出了独特的要求；他们缺乏紧密的 交叉口，调节交通的结构 细胞外裂隙，仅含有少量 Na,K- ATPase，一种通过移动来维持细胞静息电位的酶 Na+ 和 K+ 与电化学梯度的关系。主要目标 该应用程序是研究通道的结构和功能 小牛晶状体中纤维细胞之间的通讯（细胞间通讯） 渠道）。这些通道形成了一条主要负责 代谢物、废物和水在纤维中的扩散 细胞。该申请提出净化纤维细胞间通道 使用非离子洗涤剂和柱从小牛镜片中提取 色谱法。建议进行实验以确定是否 纤维细胞间通道由一种连接蛋白（同型）或 两个（即“混合”通道）。纯化的细胞间通道将 二维片状结晶及其结构研究 冷冻电子显微镜和计算机图像处理。纯化后的 通道也将在平面脂质双层中重建 在单通道和多通道级别上进行电气表征。 该应用程序的另一个目的是研究专门的途径 称为缝线的晶状体区域是由相互作用形成的 来自晶状体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 裂缝构成了进入晶状体内部的直接通道。 还缝合 含有大量可能发挥功能的膜囊泡和小管 通过胞饮作用将分子运输到纤维细胞中 机制。纤维结构与功能的研究进展 细胞间通道和缝合线对于理解很重要 涉及维持晶状体透明度的机制以及 白内障的形成，这是晶状体的主要疾病。