Langley R C, Cohen C M
J Cell Biochem. 1986;30(2):101-9. doi: 10.1002/jcb.240300202.
The association of erythrocyte spectrin with desmin filaments was investigated using two in vitro assays. The ability of spectrin to promote the interaction of desmin filaments with membranes was investigated by electron microscopy of desmin filament-erythrocyte inside-out vesicle preparations. Desmin filaments bound to erythrocyte inside-out vesicles in a spectrin-dependent manner, demonstrating that spectrin is capable of mediating the association of desmin filaments with plasma membranes. A quantitative sedimentation assay was used to demonstrate the direct association of spectrin with desmin filaments in vitro. When increasing concentrations of spectrin were incubated with desmin filaments, spectrin cosedimented with desmin filaments in a concentration-dependent manner. At near saturation the spectrin:desmin molar ratio in the sedimented complex was 1:230. Our results suggest that, in addition to its well characterized associations with actin, spectrin functions to mediate the association of intermediate filaments with plasma membranes. It might be that nonerythrocyte spectrins share erythrocyte spectrin's ability to bind to intermediate filaments and function in nonerythroid cells to promote the interaction of intermediate filaments with actin filaments and/or the plasma membrane.
利用两种体外试验研究了红细胞血影蛋白与结蛋白丝的关联。通过对结蛋白丝-红细胞内翻囊泡制剂进行电子显微镜观察，研究了血影蛋白促进结蛋白丝与膜相互作用的能力。结蛋白丝以血影蛋白依赖的方式与红细胞内翻囊泡结合，表明血影蛋白能够介导结蛋白丝与质膜的关联。采用定量沉降试验来证明血影蛋白与结蛋白丝在体外的直接关联。当将浓度不断增加的血影蛋白与结蛋白丝一起孵育时，血影蛋白以浓度依赖的方式与结蛋白丝共同沉降。在接近饱和时，沉降复合物中血影蛋白与结蛋白的摩尔比为1:230。我们的结果表明，除了其与肌动蛋白的已充分表征的关联外，血影蛋白还起到介导中间丝与质膜关联的作用。可能非红细胞血影蛋白具有与红细胞血影蛋白相同的结合中间丝的能力，并在非红细胞中发挥作用，以促进中间丝与肌动蛋白丝和/或质膜的相互作用。
