Capanni Cristina, Sabatelli Patrizia, Mattioli Elisabetta, Ognibene Andrea, Columbaro Marta, Lattanzi Giovanna, Merlini Luciano, Minetti Carlo, Maraldi Nadir M, Squarzoni Stefano
Lab. Biologia Cellulare e Microscopia Elettronica IOR, Bologna, Italy.
Exp Mol Med. 2003 Dec 31;35(6):538-44. doi: 10.1038/emm.2003.70.
Dysferlin is a plasma membrane protein of skeletal muscle whose deficiency causes Miyoshi myopathy, limb girdle muscular dystrophy 2B and distal anterior compartment myopathy. Recent studies have reported that dysferlin is implicated in membrane repair mechanism and coimmunoprecipitates with caveolin 3 in human skeletal muscle. Caveolin 3 is a principal structural protein of caveolae membrane domains in striated muscle cells and cardiac myocytes. Mutations of caveolin 3 gene (CAV3) cause different diseases and where caveolin 3 expression is defective, dysferlin localization is abnormal. We describe the alteration of dysferlin expression and localization in skeletal muscle from a patient with raised serum creatine kinase (hyperCKaemia), whose reduction of caveolin 3 is caused by a CAV3 P28L mutation. Moreover, we performed a study on dysferlin interaction with caveolin 3 in C2C12 cells. We show the association of dysferlin to cellular membrane of C2C12 myotubes and the low affinity link between dysferlin and caveolin 3 by immunoprecipitation techniques. We also reproduced caveolinopathy conditions in C2C12 cells by a selective p38 MAP kinase inhibition with SB203580, which blocks the expression of caveolin 3. In this model, myoblasts do not fuse into myotubes and we found that dysferlin expression is reduced. These results underline the importance of dysferlin-caveolin 3 relationship for skeletal muscle integrity and propose a cellular model to clarify the dysferlin alteration mechanisms in caveolinopathies.
肌膜蛋白是一种骨骼肌的质膜蛋白，其缺乏会导致宫下肌病、2B型肢带型肌营养不良和远端前间隔肌病。最近的研究报道，肌膜蛋白参与膜修复机制，并在人类骨骼肌中与小窝蛋白3共同免疫沉淀。小窝蛋白3是横纹肌细胞和心肌细胞中小窝膜结构域的主要结构蛋白。小窝蛋白3基因（CAV3）的突变会导致不同的疾病，并且在小窝蛋白3表达缺陷的情况下，肌膜蛋白的定位会异常。我们描述了一名血清肌酸激酶升高（高肌酸激酶血症）患者骨骼肌中肌膜蛋白表达和定位的改变，其小窝蛋白3的减少是由CAV3 P28L突变引起的。此外，我们对C2C12细胞中肌膜蛋白与小窝蛋白3的相互作用进行了研究。我们通过免疫沉淀技术显示了肌膜蛋白与C2C12肌管细胞膜的关联以及肌膜蛋白与小窝蛋白3之间的低亲和力联系。我们还通过用SB203580选择性抑制p38丝裂原活化蛋白激酶在C2C12细胞中重现了小窝蛋白病的情况，该抑制剂会阻断小窝蛋白3的表达。在这个模型中，成肌细胞不会融合形成肌管，并且我们发现肌膜蛋白的表达减少。这些结果强调了肌膜蛋白-小窝蛋白3关系对骨骼肌完整性的重要性，并提出了一个细胞模型来阐明小窝蛋白病中肌膜蛋白改变的机制。
