Nelson W J, Lazarides E
Nature. 1983;304(5924):364-8. doi: 10.1038/304364a0.
Spectrin comprises a family of polypeptides thought to be involved in mediating linkage of actin filaments to the plasma membrane in a wide variety of cell types (for reviews see refs 1-3). Spectrin is present as a tetramer composed of two non-identical subunits. Most cells express a common subunit with a molecular weight (Mr) of 240,000 (240 K; termed alpha-spectrin) in association with a polymorphic cell type-specific subunit: Mr 260 K in the intestinal terminal web (termed TW260), Mr 235 K in nervous tissue., liver, lymphocytes and fibroblasts (termed gamma-spectrin; also referred to as fodrin), and Mr 225/220 K in erythrocytes and adult cardiac and skeletal muscle (termed beta'- and beta-spectrin, respectively). We show here that primary chicken myoblasts express predominantly alpha gamma-spectrin, but on terminal differentiation in vitro the cells gradually switch to alpha beta-spectrin as a result of the onset of beta- and beta'-spectrin synthesis and by the subsequent differential stabilization of beta- and gamma-spectrin. This switching correlates with known changes in the biophysical properties and function of the developing muscle sarcolemma and cytoskeleton.
血影蛋白由一族多肽组成，据认为在多种细胞类型中介导肌动蛋白丝与质膜的连接（综述见参考文献1 - 3）。血影蛋白以由两个不同亚基组成的四聚体形式存在。大多数细胞表达一种分子量（Mr）为240,000（240K；称为α - 血影蛋白）的常见亚基，与一种多态性的细胞类型特异性亚基结合：在肠末端网中为Mr 260K（称为TW260），在神经组织、肝脏、淋巴细胞和成纤维细胞中为Mr 235K（称为γ - 血影蛋白；也称为胞衬蛋白），在红细胞以及成年心脏和骨骼肌中为Mr 225/220K（分别称为β' - 和β - 血影蛋白）。我们在此表明，原代鸡成肌细胞主要表达αγ - 血影蛋白，但在体外终末分化时，由于β - 和β' - 血影蛋白的合成起始以及随后β - 和γ - 血影蛋白的差异稳定性，细胞逐渐转变为表达αβ - 血影蛋白。这种转变与发育中的肌膜和细胞骨架的生物物理特性及功能的已知变化相关。
