Albrecht D L, Mills J W, Noelle R J
Graduate Program in Biochemistry, Dartmouth Medical School, Hanover, NH 03756.
J Immunol. 1990 May 1;144(9):3251-6.
The proposed function of intermediate filaments is to provide a cell type-specific structural framework that maintains cell shape and organelle distribution and mediates signal transduction through its connections with the plasma membrane and the nucleus. Vimentin is the intermediate filament protein expressed in B lymphocytes. Immunocytochemical analysis of the high salt-stable cytoskeletons from B cells stimulated with anti-Ig revealed an increased accumulation of vimentin in the cytoskeleton compared to nontreated controls. This increased accumulation of vimentin in the cytoskeleton was manifested by the organization of vimentin into extensive filamentous arrays (EFA) as viewed in the fluorescent microscope. In contrast to the effects of anti-Ig, activation of B cells with LPS did not induce the organization of vimentin into EFA. This suggested that signals unique to anti-Ig directed EFA formation. Immunocytochemical results were verified by biochemical analysis showing that vimentin was more abundant in isolated cytoskeletons from anti-Ig activated B cells, than cytoskeletons isolated from LPS-activated B cells. These observations established a relationship between increased content of vimentin in the cytoskeleton and the formation of EFA. By testing a wide variety of activating agents, we were able to correlate increased vimentin expression in the cytoskeleton to activating agents that cross-link membrane Ig. It appeared that treatment of B cells with LPS prohibited the induction of EFA by anti-Ig because cotreatment with both anti-Ig and LPS resulted in decreased vimentin accumulation in the cytoskeleton to a level less than that in resting cells. The significance of these results with regard to B cell biology is discussed.
中间丝的推测功能是提供一种细胞类型特异性的结构框架，以维持细胞形状和细胞器分布，并通过其与质膜和细胞核的连接介导信号转导。波形蛋白是在B淋巴细胞中表达的中间丝蛋白。对用抗Ig刺激的B细胞的高盐稳定细胞骨架进行免疫细胞化学分析发现，与未处理的对照相比，波形蛋白在细胞骨架中的积累增加。在荧光显微镜下观察，波形蛋白在细胞骨架中这种增加的积累表现为波形蛋白组织成广泛的丝状阵列（EFA）。与抗Ig的作用相反，用LPS激活B细胞不会诱导波形蛋白组织成EFA。这表明抗Ig特有的信号指导EFA的形成。免疫细胞化学结果通过生化分析得到验证，结果表明，与从LPS激活的B细胞中分离的细胞骨架相比，波形蛋白在从抗Ig激活的B细胞中分离的细胞骨架中更为丰富。这些观察结果确立了细胞骨架中波形蛋白含量增加与EFA形成之间的关系。通过测试多种激活剂，我们能够将细胞骨架中波形蛋白表达的增加与交联膜Ig的激活剂联系起来。似乎用LPS处理B细胞会抑制抗Ig诱导EFA，因为同时用抗Ig和LPS处理会导致细胞骨架中波形蛋白的积累减少到低于静息细胞中的水平。本文讨论了这些结果对B细胞生物学的意义。
