Chopard A, Pons F, Marini J F
Laboratoire de Physiologie Cellulaire et Moléculaire des Systèmes Intégrés, Centre National de la Recherche Scientifique Unité Mixte de Recherche 6548, Faculté des Sciences, 06108 Nice Cedex 2, France.
Am J Physiol Regul Integr Comp Physiol. 2001 Feb;280(2):R323-30. doi: 10.1152/ajpregu.2001.280.2.R323.
Transversal cytoskeletal organization of muscle fibers is well described, although very few data are available concerning protein content. Measurements of desmin, alpha-actinin, and actin contents in soleus and extensor digitorum longus (EDL) rat skeletal muscles, taken with the results previously reported for several dystrophin-glycoprotein complex (DGC) components, indicate that the contents of most cytoskeletal proteins are higher in slow-type fibers than in fast ones. The effects of hypokinesia and unloading on the cytoskeleton were also investigated, using hindlimb suspension. First, this resulted in a decrease in contractile protein contents, only after 6 wk, in the soleus. Dystrophin and associated proteins were shown to be reduced for soleus at 3 wk, whereas only the dystrophin-associated proteins were found to increase after 6 wk. On the other hand, the contents of DGC components were increased for EDL for the two durations. Desmin and alpha-actinin levels were unchanged in the same conditions. Consequently, it can be concluded that the cytoskeletal protein expression levels could largely contribute to muscle fiber adaptation induced by modified functional demands.
肌肉纤维的横向细胞骨架组织已有充分描述，尽管关于蛋白质含量的数据非常少。对大鼠比目鱼肌和趾长伸肌（EDL）中结蛋白、α-辅肌动蛋白和肌动蛋白含量的测量，结合先前报道的几种肌营养不良蛋白-糖蛋白复合物（DGC）成分的结果，表明大多数细胞骨架蛋白的含量在慢肌纤维中高于快肌纤维。还使用后肢悬吊研究了运动减少和卸载对细胞骨架的影响。首先，这仅在6周后导致比目鱼肌收缩蛋白含量下降。结果显示，3周时比目鱼肌中的肌营养不良蛋白及相关蛋白减少，而6周后仅发现肌营养不良蛋白相关蛋白增加。另一方面，在两个时间段内，EDL的DGC成分含量均增加。在相同条件下，结蛋白和α-辅肌动蛋白水平未发生变化。因此，可以得出结论，细胞骨架蛋白表达水平在很大程度上可能有助于因功能需求改变而引起的肌纤维适应。
