GAP JUNCTION

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 缝隙连接是在细胞-细胞并置区发现的质膜特化。 它们含有成千上万的通道，允许分子的运动， kDa或更小。缝隙连接通道是由 连接蛋白（Cx）蛋白家族，大小范围从~23 kDa到~62 kDa，尽管 大多数研究的连接蛋白是Cx 26（26 kDa）、Cx 32（32 kDa）和Cx43（43 kDa）。的间隙 连接通道由两个连接蛋白六聚体（半通道）组成，每个连接蛋白六聚体来自 相互作用的细胞背靠背地堆叠在一起。单粒子重建用于 合成连接蛋白50（Cx 50）三级结构的更完整视图 半通道Cx 50缝隙连接在透镜和功能障碍中起重要作用， Cx 50突变体的误转染导致先天性白内障。差距的结构研究 使用电子或X射线晶体学方法的结沟道已经获得了原子 或用于Cx 26和C-末端截短的Cx 43的近原子分辨率结构。刚性 跨膜和细胞外结构域的解决，但灵活的细胞质环， 和C-末端由于紊乱或截短而没有充分显现。 在大于~40 kDa的连接蛋白中，这些胞质结构域，特别是C- 末端，通常含有与N-末端一样多的氨基酸，跨膜和 细胞外结构域组合。这些胞质结构域含有重要的激酶 PDZ结构域蛋白（例如ZO-1）、微管蛋白、去磷酸化蛋白的调节结构域和结合位点 (an肌动蛋白结合蛋白）和可能的钙粘蛋白或β-连环蛋白。因此 晶体结构缺少结构的重要部分。我们取得了 Cx 50 pannexons的玻璃化冷冻电镜成像及重建研究进展 单粒子方法。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Gap junctions are plasma membrane specializations found at cell-cell appositional areas. They contain tens to thousands of channels that allow the movement of molecules of 1 kDa or less between neighboring cells. Gap junction channels are built from members of the connexin (Cx) protein family, ranging in size from ~23 kDa to ~62 kDa, although the most studied connexins are Cx26 (26 kDa), Cx32 (32 kDa) and Cx43 (43 kDa). A gap junction channel consists of two connexin hexamers (hemichannels), one from each of the interacting cells, stacked back-to-back. Single particle reconstruction is being used to synthesize a more complete view of the tertiary structure of Connexin50 (Cx50) hemichannels. Cx50 gap junctions play important roles in the lens and dysfunction or mistrafficking of Cx50 mutants results in congenital cataracts. Structural studies of gap junction channels using electron or X-ray crystallographic methods have obtained atomic or near atomic resolution structures for Cx26 and a C-terminal truncated Cx43. The rigid transmembrane and extracellular domains are resolved, but the flexible cytoplasmic loop and C-terminus have not been adequately visualized either due to disorder or truncation. In connexins larger than ~40 kDa, these cytoplasmic domains, particularly the C- terminus, often contain as many amino acids as the N-terminus, transmembrane and extracellular domains combined. These cytoplasmic domains contain important kinase regulatory domains and binding sites for PDZ domain proteins (e.g. ZO-1), tubulin, debrin (an actin-binding protein) and possibly cadherins or ¿-catenin. Therefore, the crystallographic structures are missing important parts of the structure. We have made advances in imaging Cx50 pannexons using vitrified cryo-EM methods and reconstruction with single particles methods.