MEMBRANE PROTEIN DEFICIENCY OF PNH ERYTHROCYTES

补体是一个循环系统，由许多不同的 蛋白质，以其裂解动物细胞和 细菌。此应用程序寻求对一系列 补体对非致病因素影响的研究 靶细胞的裂解：亚裂解事件。这项建议 源于我们的观察，当补体在 亚细胞浓度，钠和L-葡萄糖进入细胞内 未裂解的红细胞急剧增加，尽管是暂时的，而且 然而，受影响的细胞并不像预期的那样溶解或肿胀。 我们发现，这种非致命性的渗透率增加是由 膜攻击复合体，它是一种大分子复合体 终端补充部件。进一步我们确定C8， 而不是C9，是产生亚溶质变化所必需的 渗透性和对亚溶质补体的反应 发作时，钙依赖的钾通透性被激活 路径。这会促进净K外流，并防止 胶体渗透性肿胀和溶解时发生的膜 损伤是永久性的，并允许受影响的细胞存活。 在PNH中，一种疾病的特征是 红细胞对补体溶解的敏感性，有 显然，由于目前还没有的原因，缺乏亚分辨率的改变 完全理解。我们的具体目标包括：1)继续我们的 补体调节蛋白DAF和C8BP的研究 特别是与它们在次要事件中的作用有关；2) 进一步表征了瞬时渗透率的变化和 离子通量研究中的体积调节输运机制 在接触亚溶血补体的过程中；以及3)确定 亚致死事件对细胞的生物学影响 在补给攻击中幸存下来。我们将在正常和 PNH红细胞，以及携带异常血红蛋白的细胞， 例如已知具有音量调节SS、SC或CC 我们预测的通路会降低它们对 补体溶解。我们希望我们的调查能有所帮助。 更好地了解补体介导的疾病，如狼疮 红斑性和免疫性溶血性贫血，还提供 有关细胞生理功能的重要信息 补体系统及其调节蛋白。

Complement is a circulating system composed of many different proteins which is known for its ability to lyse animal cells and bacteria. This application seeks support for a series of investigations on the effects of complement on that do not lead to lysis of the target cell: the sublytic events. This proposal stems from our observation that when complement is activated at sublytical concentrations, influx of Na and L-glucose into the unlysed erthrocytes increases dramatically, albeit transiently, and yet the affected cells do not lyse or swell, as would be expected. We found that this non-lethal permeability increase is produced by the membrane attack complex, which is a macromolecular complex of the terminal complement components. Further we determined that C8, but not C9, is necessary to produce the sublytic change in permeability and that in response to the sublytic complement attack, there is activation of a Ca-dependent K permeability pathway. This promotes net K efflux and prevents the colloidosmotic swelling and lysis that occurs when the membrane damage is permanent and permits the survival of the affected cell. In PNH, a disease characterized by a dramatic increase in the sensitivity of erythrocytes to complement lysis, there is apparently a lack of sublytic changes for reasons not yet completely understood. Our specific aims include: 1) continue our studies on the complement regulatory proteins DAF and C8bp, particularly in relation to their role in the sublytic events; 2) characterize further the transient permeability changes and the volume regulatory transport mechanism through studies on ion fluxes during exposure to sublytic complement; and 3) determine the biological consequences of the sublytic events to the cells that survive a complement attack. We will perform studies in normal and PNH erthrocytes, as well as in cells carrying abnormal hemoglobin, such as SS, SC, or CC which are known to have volume regulatory pathways that we predict would decrease their sensitivity to complement lysis. We expect that our investigations will help better understanding complement mediated diseases, such as lupus erythematous and immune hemolytic anemia, and also provide important information on the physiological functions of the complement system and its regulatory proteins.