Ohlendieck K
Department of Pharmacology, University College Dublin, Ireland.
Eur J Cell Biol. 1996 Jan;69(1):1-10.
In muscle, the large membrane cytoskeletal protein dystrophin is tightly associated with several sarcolemmal proteins. It is now well established that the extracellular 156 kDa dystrophin-associated glycoprotein alpha-dystroglycan is a laminin binding protein which is linked to the sarcolemma via an integral glycoprotein complex. Beta-dystroglycan of 43 kDa, together with the 50 kDa protein adhalin and three other dystrophin-associated glycoproteins of 25, 35 and 43 kDa form this sarcolemmal complex which binds to the cysteine-rich domain of dystrophin. While the carboxy-terminal domain of dystrophin is associated with the syntrophin triplet of apparent 59 kDa, the amino-terminal dystrophin domain binds to the subsarcolemmal actin cytoskeleton. Numerous studies into the molecular pathogenesis of muscular dystrophies and cardiomyopathies suggest that primary defects in components of the dystrophin-glycoprotein complex are responsible for certain forms of these muscular disorders. Disturbances in the composition of the dystrophin-glycoprotein complex in skeletal and cardiac muscle seem to disrupt the linkage between the extracellular matrix and the actin membrane cytoskeleton which might render muscle fibers more susceptible to necrosis. In normal muscle, the vital function of the dystrophin-glycoprotein complex appears to be the stabilization of the muscle cell periphery during contraction.
在肌肉中，大型膜细胞骨架蛋白肌营养不良蛋白与几种肌膜蛋白紧密相关。现已明确，细胞外156 kDa的肌营养不良蛋白相关糖蛋白α-肌营养不良聚糖是一种层粘连蛋白结合蛋白，它通过一个完整的糖蛋白复合体与肌膜相连。43 kDa的β-肌营养不良聚糖与50 kDa的蛋白整合素以及另外三种25 kDa、35 kDa和43 kDa的肌营养不良蛋白相关糖蛋白形成这个肌膜复合体，该复合体与肌营养不良蛋白富含半胱氨酸的结构域结合。虽然肌营养不良蛋白的羧基末端结构域与表观分子量为59 kDa的肌养蛋白三联体相关，但肌营养不良蛋白的氨基末端结构域与肌膜下肌动蛋白细胞骨架结合。对肌营养不良症和心肌病分子发病机制的大量研究表明，肌营养不良蛋白-糖蛋白复合体成分的原发性缺陷是这些肌肉疾病某些形式的病因。骨骼肌和心肌中肌营养不良蛋白-糖蛋白复合体组成的紊乱似乎会破坏细胞外基质与肌动蛋白膜细胞骨架之间的联系，这可能使肌纤维更容易发生坏死。在正常肌肉中，肌营养不良蛋白-糖蛋白复合体的重要功能似乎是在收缩过程中稳定肌肉细胞周边。
