MEMBRANE PROTEIN DEFICIENCY OF PNH ERYTHROCYTES

补体是由多种不同成分组成的循环系统 以其溶解动物细胞的能力而闻名的蛋白质 细菌。 该应用程序寻求一系列的支持 对补体影响的研究不会导致 靶细胞的裂解：亚裂解事件。 这个提议 源于我们的观察，当补体被激活时 sublytical concentrations, influx of Na and L-glucose into the 未溶解的红细胞急剧增加，尽管是短暂的，并且 然而，受影响的细胞并没有像预期的那样裂解或肿胀。 我们发现这种非致命的渗透性增加是由 膜攻击复合物，是一种大分子复合物 末端补体成分。 进一步我们确定 C8， 但不是 C9，是产生微妙变化所必需的 渗透性和对亚裂解补体的反应 攻击时，Ca 依赖性 K 渗透性被激活 途径。 这促进了净 K 流出并防止 colloidosmotic swelling and lysis that occurs when the membrane 损伤是永久性的，并允许受影响的细胞存活。 In PNH, a disease characterized by a dramatic increase in the 红细胞对补体裂解的敏感性， 显然由于尚未发生的原因而缺乏微妙的变化 完全明白了。 我们的具体目标包括：1）继续我们的 studies on the complement regulatory proteins DAF and C8bp, particularly in relation to their role in the sublytic events; 2） 进一步表征瞬时渗透率变化和 通过离子通量研究的体积调节运输机制 在暴露于亚裂解补体期间； 3) 确定 亚裂解事件对细胞的生物学影响 在补体攻击中幸存下来。 我们将在正常和 PNH 红细胞以及携带异常血红蛋白的细胞， such as SS, SC, or CC which are known to have volume regulatory pathways that we predict would decrease their sensitivity to 补体裂解。 我们希望我们的调查能够有所帮助 更好地了解补体介导的疾病，例如狼疮 erythematous and immune hemolytic anemia, and also provide 有关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.