Ozawa E
National Institute of Neuroscience, NCNP, Tokyo, Japan.
Nihon Shinkei Seishin Yakurigaku Zasshi. 1995 Jun;15(3):289-93.
Dystrophin is a protein product of the gene responsible for Duchenne muscular dystrophy (DMD), and is a long slender protein localized at the protoplasmic surface of sarcolemma. Dystrophin binds with actin filaments at its amino-terminal region, and with dystrophin-associated proteins (DAPs) at its carboxyl-terminal region. DAPs are composed of a glycoprotein complex and a syntrophin complex, a complex of proteins binding with dystrophin and located intracellularly. Glycoprotein complex is composed of dystroglycan complex and sarcoglycan complex, both of which are membrane-integrated. Dystrophin binds with dystroglycan complex which transverse through sarcolemma and then binds with laminin in the basal lamina, forming a long axis between action threads and the extracellular matrix. Sarcoglycan complex does not directly bind with dystrophin but binds with dystroglycan complex. Disruption of the axis results in dystrophic changes in one kind of congenital muscular dystrophy (CMD). Loss of the sarcoglycan complex gives rise to childhood severe autosomal recessive muscular dystrophy (SCARMD) which is clinically very similar to DMD. In DMD, the sarcoglycan complex is mostly lost, and the axis is for the most part defective. Therefore, it is likely that the causes of DMD and SCARMD may be similar and may be modified by the mechanism which gives rise to CMD.
肌营养不良蛋白是负责杜兴氏肌营养不良症（DMD）的基因的蛋白质产物，是一种细长的蛋白质，定位于肌膜的原生质表面。肌营养不良蛋白在其氨基末端区域与肌动蛋白丝结合，在其羧基末端区域与肌营养不良蛋白相关蛋白（DAPs）结合。DAPs由糖蛋白复合物和肌萎缩蛋白复合物组成，肌萎缩蛋白复合物是一种与肌营养不良蛋白结合并位于细胞内的蛋白质复合物。糖蛋白复合物由肌营养不良聚糖复合物和肌聚糖复合物组成，两者均整合于细胞膜。肌营养不良蛋白与穿过肌膜的肌营养不良聚糖复合物结合，然后与基底膜中的层粘连蛋白结合，在肌动蛋白丝和细胞外基质之间形成一个长轴。肌聚糖复合物不直接与肌营养不良蛋白结合，而是与肌营养不良聚糖复合物结合。该轴的破坏会导致一种先天性肌营养不良症（CMD）出现营养不良性变化。肌聚糖复合物的缺失会导致儿童严重常染色体隐性肌营养不良症（SCARMD），其临床表现与DMD非常相似。在DMD中，肌聚糖复合物大多缺失，且该轴大多存在缺陷。因此，DMD和SCARMD的病因可能相似，且可能由引发CMD的机制所改变。
