Membrane assembly and remodeling during reticulocyte maturation
Membrane assembly and remodeling during reticulocyte maturation
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DOI：
10.1182/blood.v74.3.1112.bloodjournal7431112
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发表时间：
1989-08
期刊：
影响因子：
20.3
通讯作者：
J. Chasis;M. Prenant;A. Leung;N. Mohandas
中科院分区：
文献类型：
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作者：
J. Chasis;M. Prenant;A. Leung;N. Mohandas
膜骨架和细胞骨架重塑发生在整个红系成熟。微管和微丝在有核成红细胞中已被形态学鉴定，但这些细胞骨架结构在网织红细胞成熟过程中的功能尚未研究。网织红细胞由正染性正常成红细胞通过核挤出过程形成。网织红细胞成熟的两个可识别的阶段如下。最不成熟的网织红细胞是活动的和多小叶的，而更成熟的网织红细胞是杯形的和非运动的。为了研究微管和微丝在核挤出和细胞运动中的各自作用，用扰乱这些结构的试剂进行实验。在向大鼠注射秋水仙碱（一种微管破坏物质）后，在细胞核挤出阶段被捕的正常成红细胞数量在4小时内线性增加。当骨髓细胞在秋水仙碱存在下培养时，也得到了类似的结果。相反，细胞松弛素B，一种微生物破坏剂，细胞运动性显着下降，但不是秋水仙素。这些结果表明，微管是必不可少的核挤出过程中，而微丝是必不可少的细胞运动。膜骨架组装的同时变化进行了评估，通过测量膜变形性和稳定性，两个属性调节的骨架蛋白。在Ektacytometric分析中，未成熟网织红细胞的膜变形性和机械稳定性显著降低至正常的约10%，而更成熟的网织红细胞几乎正常。由于骨架蛋白组织调节这些膜的特性，我们的研究结果表明，大量的膜骨架重塑发生在网织红细胞成熟。因此，我们已经确定在网织红细胞成熟过程中骨骼和细胞骨架成分的主要重塑。
Membrane skeletal and cytoskeletal remodeling occurs throughout erythroid maturation. Microtubules and microfilaments have been identified morphologically in the nucleated erythroblast but the functional capability of these cytoskeletal structures during reticulocyte maturation has not been studied. Reticulocytes are formed from orthochromatic normoblasts by the process of nuclear extrusion. Two recognizable stages of reticulocyte maturation follow. The least mature reticulocytes are motile and multilobular, while the more mature reticulocytes are cup-shaped and nonmotile. To study the respective roles of microtubules and microfilaments in nuclear extrusion and cell motility, experiments were performed with agents that perturb these structures. Following the injection into rats of colchicine, a microtubule-disrupting substance, the number of normoblasts arrested at the stage of nuclear extrusion increased linearly over four hours. Similar results were obtained when bone marrow cells were incubated in culture in the presence of colchicine. In contrast, cell motility was dramatically decreased by cytochalasin B, a microfilament-disrupting agent, but not by colchicine. These results imply that microtubules are essential for the nuclear extrusion process, while microfilaments are essential for cell motility. Simultaneous changes in membrane skeletal assembly were assessed by measuring membrane deformability and stability, two properties regulated by the skeletal proteins. In ektacytometric assays, membrane deformability and mechanical stability of immature reticulocytes were markedly decreased to approximately 10% of normal, while that of more mature reticulocytes were nearly normal. Since the skeletal protein organization regulates these membrane properties, our findings imply that substantial membrane skeletal remodeling occurs during reticulocyte maturation. Thus we have identified major remodeling of both skeletal and cytoskeletal components during reticulocyte maturation.