Ohlendieck K, Ervasti J M, Snook J B, Campbell K P
Howard Hughes Medical Institute, University of Iowa College of Medicine, Iowa City 52242.
J Cell Biol. 1991 Jan;112(1):135-48. doi: 10.1083/jcb.112.1.135.
mAbs specific for protein components of the surface membrane of rabbit skeletal muscle have been used as markers in the isolation and characterization of skeletal muscle sarcolemma membranes. Highly purified sarcolemma membranes from rabbit skeletal muscle were isolated from a crude surface membrane preparation by wheat germ agglutination. Immunoblot analysis of subcellular fractions from skeletal muscle revealed that dystrophin and its associated glycoproteins of 156 and 50 kD are greatly enriched in purified sarcolemma vesicles. The purified sarcolemma was also enriched in novel sarcolemma markers (SL45, SL/TS230) and Na+/K(+)-ATPase, whereas t-tubule markers (alpha 1 and alpha 2 subunits of dihydropyridine receptor, TS28) and sarcoplasmic reticulum markers (Ca2(+)-ATPase, ryanodine receptor) were greatly diminished in this preparation. Analysis of isolated sarcolemma by SDS-PAGE and densitometric scanning demonstrated that dystrophin made up 2% of the total protein in the rabbit sarcolemma preparation. Therefore, our results demonstrate that although dystrophin is a minor muscle protein it is a major constituent of the sarcolemma membrane in skeletal muscle. Thus the absence of dystrophin in Duchenne muscular dystrophy may result in a major disruption of the cytoskeletal network underlying the sarcolemma in dystrophic muscle.
针对兔骨骼肌表面膜蛋白成分的单克隆抗体已被用作分离和鉴定骨骼肌肌膜的标志物。通过麦胚凝集从粗制表面膜制剂中分离出高度纯化的兔骨骼肌肌膜。对骨骼肌亚细胞组分的免疫印迹分析表明，肌营养不良蛋白及其156和50kD的相关糖蛋白在纯化的肌膜小泡中大量富集。纯化的肌膜还富含新型肌膜标志物（SL45、SL/TS230）和Na+/K(+)-ATP酶，而横管标志物（二氢吡啶受体的α1和α2亚基，TS28）和肌浆网标志物（Ca2(+)-ATP酶、兰尼碱受体）在该制剂中大量减少。通过SDS-PAGE和光密度扫描对分离的肌膜进行分析表明，肌营养不良蛋白占兔肌膜制剂总蛋白的2%。因此，我们的结果表明，尽管肌营养不良蛋白是一种次要的肌肉蛋白，但它是骨骼肌肌膜的主要成分。因此，杜兴氏肌营养不良症中肌营养不良蛋白的缺失可能导致营养不良肌肉中肌膜下细胞骨架网络的重大破坏。
