PHYSIOLOGY OF RECONSTITUTED GAP JUNCTION CHANNELS

缝隙结是离子直接转移的轨迹和小的 分子从一个细胞到另一个细胞。它由一系列蛋白质组成 两个相邻细胞质膜中的分子，形成一个 连接细胞质的水通道。在…的基础上 耐人寻味的间接证据，人们普遍认为 由连接通道介导的细胞间通信必须是 对许多组织的正常发育和成熟功能很重要。 最近有一点变得很清楚，即电导率和渗透率 连接通道可受电压、pH、钙的动态调节 离子和环核苷酸。因此，有关渠道如何 函数，它是如何选通的，以及它可能经历的内容 兴趣超越了其生物物理方面。 该建议是针对大鼠连接通道的研究而提出的 肝脏在平面脂质双层中重建。它建立在(1)过去工作的基础上 中描述了连接通道的选通特性 使用电生理学方法的细胞膜，以及(2)初步 在实验中，具有许多交界点特性的通道 通道被结合到平面双层中，具有隔离的间隙 结合部作为起始材料。现建议(A)改善 重组的效率，(B)研究门控和选择性 重构的连接通道，具体地关于电压， PH和渗透效应(C)测试结合蛋白的抗血清 对重组渠道的功能影响，广告(D)并入 脂双层编码的RNA的体外翻译产物 结合蛋白。 通过对经络生理学的研究，人们希望了解 细胞可以调节这种形式的细胞间的机制 沟通。通过缝隙连接进行耦合是如此普遍，以至于 对这一过程的阐明无疑将对许多 细胞生物学和发育生物学领域。

The gap junction is the locus of direct transfer of ions and small molecules from cell to cell. It is composed of an array of protein molecules in the plasma membranes of two abutting cells which form an aqueous channel connecting the cytoplasms of the cells. On the basis of intriguing circumstantial evidence, it is widely held that the intercellular communication mediated by junctional channels must be important in the normal development and mature function of many tissues. Recently it has become clear that the conductance and permeability of the junctional channel can be dynamically regulated by voltage, pH, calcium ions and cyclic nucleotides. Therefore information about how the channel functions, how it is gated, and what goes through it is likely to be of interest beyond its biophysical aspects. The proposal is directed toward the study of junctional channels from rat liver reconstituted in planar lipid bilayers. It builds on (1) past work which characterized the gating properties of junctional channels in cellular membranes using electrophysiological methods, and (2) preliminary experiments in which channels with many of the properties of junctional channels were incorporated into planar bilayers, with isolated gap junctions as the starting material. It is proposed to (a) improve the efficiency of the reconstitution, (b) to study the gating and selectivity of the reconstituted junctional channels, specifically regarding voltage, pH and osmotic effects (c) to test antisera against junctional protein for functional effects on reconstituted channels, ad (d) to incorporate into lipid bilayers the products of in vitro translation of RNA coding for junctional protein. Through such studies of channel physiology, one hopes to understand the mechanisms by which cells can modulate this form of intercellular communication. Coupling by way of gap junctions is so widespread that elucidation of this process will undoubtedly have profound effects in many areas of cellular and developmental biology.