Role of the reticulum in the stability and shape of the isolated human erythrocyte membrane.
Role of the reticulum in the stability and shape of the isolated human erythrocyte membrane.
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DOI：
10.1083/jcb.92.3.714
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发表时间：
1982-03
期刊：
影响因子：
--
通讯作者：
Steck TL
中科院分区：
文献类型：
--
作者：
Lange Y;Hadesman RA;Steck TL
为了检验广泛持有的假设，即覆盖人红细胞膜细胞质表面的蛋白质网状结构控制细胞稳定性和形状，我们评估了其一些特性。通过 Triton X-100 萃取除去双层的网状结构在生理离子强度下机械稳定，但在低离子强度下物理不稳定。网状结构在一段特征性的滞后期后分解，该滞后期在 0 至 37 摄氏度之间下降了 500 倍。多肽带 4.1 从网状结构中的释放先于血影蛋白和肌动蛋白，表明带 4.1 可能稳定整体，但对其完整性而言并不是必需的。鬼魂、鬼魂内部的网织体和孤立的网织体的分解时间过程相似。然而，在离子强度非常低的情况下，网状结构在幽灵内部的稳定性不如自由状态下的稳定。在较高离子强度下，情况正好相反。在多种条件下，随着网状结构的瓦解，膜也会分解成囊泡，这可能是因为该网络对双层进行了机械稳定。鬼影和裸网的体积均与离子强度成反比且可逆地变化。裸网状体的体积变化比幽灵大得多，这表明它的变形通常受到可扩展性较差的双层的限制。分离的网状体的轮廓是盘状的，并且经常有凹痕或锯齿状，如用异硫氰酸荧光素标记鬼影后在荧光显微镜中可见的那样。来自在等渗盐水中失去了圆齿能力的幽灵的网状结构会枯萎，尽管双层是光滑且扩张的。相反，由二硝基苯酚形成圆齿状的鬼影则产生光滑、扩张的网状结构。我们得出的结论是，网状结构是一个耐用、柔韧和有弹性的网络，它承担并稳定了膜的轮廓，但不负责其圆齿形。
In order to examine the widely held hypothesis that the reticulum of proteins which covers the cytoplamsic surface of the human erythrocyte membrane controls cell stability and shape, we have assessed some of its properties. The reticulum, freed of the bilayer by extraction with Triton X-100, was found to be mechanically stable at physiological ionic strength but physically unstable at low ionic strength. The reticulum broke down after a characteristic lag period which decreased 500-fold between 0 degrees and 37 degrees C. The release of polypeptide band 4.1 from the reticulum preceded that of spectrin and actin, suggesting that band 4.1 might stabilize the ensemble but is not essential to its integrity. The time-course of breakdown was similar for ghosts, the reticulum inside of ghosts, and the isolated reticulum. However, at very low ionic strength, the reticulum was less stable within the ghost than when free; at higher ionic strength, the reverse was true. Over a wide range of conditions the membrane broke down to vesicles just as the reticulum disintegrated, presumably because the bilayer was mechanically stabilized by this network. The volume of both ghosts and naked reticula varied inversely and reversibly with ionic strength. The volume of the naked reticulum varied far more widely than the ghost, suggesting that its deformation was normally limited by the less extensible bilayer. The contour of the isolated reticulum was discoid and often dimpled or indented, as visualized in the fluorescence microscope after labeling of the ghosts with fluoroscein isothiocyanate. Reticula derived from ghosts which had lost the ability to crenate in isotonic saline were shriveled, even though the bilayer was smooth and expanded. Conversly, ghosts crenated by dinitrophenol yielded smooth, expanded reticula. We conclude that the reticulum is a durable, flexible, and elastic network which assumes and stabilizes the contour of the membrane but is not responsible for its crenation.