Plectin tethers desmin intermediate filaments onto subsarcolemmal dense plaques containing dystrophin and vinculin
Plectin tethers desmin intermediate filaments onto subsarcolemmal dense plaques containing dystrophin and vinculin
复制标题
DOI：
10.1007/s00418-003-0496-5
复制
发表时间：
2003-02-01
影响因子：
2.3
通讯作者：
Yorifuji, H
中科院分区：
文献类型：
--
作者：
Hijikata, T;Murakami, T;Yorifuji, H
Plectin是一种多功能的细胞骨架连接蛋白，在肌肉、上皮细胞和其他组织中优先定位于中间丝和质膜之间的界面。它的缺乏导致肌肉营养不良伴单纯性大疱性表皮松解症。为了更好地了解plectin在骨骼肌肌膜下的功能作用，并深入了解plectin缺陷性肌营养不良的潜在机制，我们在体内研究了plectin与大鼠骨骼肌肌膜下细胞骨架成分如结蛋白、dystrophin和vinculin的结构和分子关系。免疫金电镜示粘连蛋白细丝将结蛋白中间丝系在肌膜下致密斑块上，覆盖Z线和I带。这些致密的斑块中含有抗肌营养不良蛋白和纽蛋白，因此可能是胞囊的结构基础。通过免疫沉淀实验证明了plectin与结蛋白、(偏位)纽蛋白、抗肌营养不良蛋白和肌动蛋白的体内结合。用明胶蛋白处理plectin免疫沉淀物，减少了肌动蛋白、dystrophin和(meta-)vinculin，但不减少结蛋白，提示肌膜下肌动蛋白可能部分介导了plectin与dystrophin或(meta-)vinculin之间的相互作用。总之，我们的数据表明，凝集素和结蛋白中间丝在肌膜下细胞骨架的稳定中可能起着至关重要的结构作用。
Plectin is a versatile cytoskeletal linker protein that preferentially localizes at interfaces between intermediate filaments and the plasma membrane in muscle, epithelia] cells, and other tissues. Its deficiency causes muscular dystrophy with epidermolysis bullosa simplex. To better understand the functional roles of plectin beneath the sarcolemma of skeletal muscles and to gain some insights into the underlying mechanism of plectin-deficient muscular dystrophy, we studied in vivo structural and molecular relationships of plectin to subsarcolemmal cytoskeletal components, such as desmin, dystrophin, and vinculin, in rat skeletal muscles. Immunogold electron microscopy revealed that plectin fine threads tethered desmin intermediate filaments onto subsarcolemmal dense plaques overlying Z-lines and I-bands. These dense plaques were found to contain dystrophin and vinculin, and thus may be the structural basis of costameres. The in vivo association of plectin with desmin, (meta-)vinculin, dystrophin, and actin was demonstrated by immunoprecipitation experiments. Treatment of plectin immunoprecipitates with gelsolin reduced actin, dystrophin, and (meta-)vinculin but not desmin, implicating that subsarcolemmal actin could partly mediate the interaction between plectin and dystrophin or (meta-)vinculin. Altogether, our data suggest that plectin, along with desmin intermediate filaments, might serve a vital structural role in the stabilization of the subsarcolemmal cytoskeleton.