PHYSIOLOGY OF CARDIAC GAP JUNCTIONS

来自不同组织的缝隙连接显示出相当大的多样性， 结构和功能特性。 然而，它还没有被 确定功能差异是否可以定位到特定的 蛋白质的结构域。 此外，生理 这种多样性的重要性仍然未知。 这个项目的目标 是为了确定间隙的结构与功能之间的关系 心脏和其他组织的连接处。 详细了解gap 连接点的运作对于我们对角色差距的整体理解至关重要 连接在正常和病理条件下均起作用。 为下一 赠款期间有三个具体目标： 1. 在大肠杆菌中表达克隆的哺乳动物和两栖动物间隙连接蛋白， 爪蟾卵母细胞表达系统，并研究其门控特性。 使用 对非洲爪蟾卵母细胞注射了mRNA，用于克隆 蛋白质，我将研究连接电导的变化， 可以直接或间接改变连接电导的试剂 (e.g.钙、质子、佛波酯、cAMP、跨接电压或 跨膜电压、局部麻醉剂。） 2. 改变缝隙连接的结构，以定位功能 蛋白质内特定结构域的通道特性。 一次 功能属性已本地化到特定域，我计划使用 定点诱变以鉴定哪些氨基酸参与了 过程 3. 表征细胞对的间隙连接电导（Gj） 分离自成年犬心房肌。

Gap junctions from different tissues show considerable diversity in structural and functional properties. However, it has not yet been determined whether the functional differences can be localized to specific structural domains of the proteins. Moreover, the physiological significance of this diversity remains unknown. The goal of this project is to determine the relation between structure and function of gap junctions in the heart and other tissues. A detailed understanding of gap junctions operate is essential to our overall understanding of the role gap junction play under both normal and pathological conditions. For the next grant period there are three specific aims: 1. To express cloned mammalian and amphibian gap junctional proteins in a Xenopus occyte expression system and study their gating properties. Using pairs of Xenopus oocytes which have been injected with mRNA for the cloned proteins, I will study changes in junctional conductance in response to agents that may either directly or indirectly modify junctional conductance (e.g. calcium, protons, phorbol esters, cAMP, transjunctional voltage or transmembrane voltage, local anesthetics.) 2. To alter the structure of gap junctions in order to localize functional properties of the channels to specific domains within the proteins. Once a functional property has been localized to a specific domain, I plan to use site directed mutagenesis to identify which amino acids are involved in the process. 3. To characterize gap junctional conductance (Gj) from cell pairs isolated from adult canine atrial muscle.