Hernández-Deviez Delia J, Martin Sally, Laval Steven H, Lo Harriet P, Cooper Sandra T, North Kathryn N, Bushby Kate, Parton Robert G
Institute for Molecular Bioscience, Centre for Microscopy and Microanalysis and School of Biomedical Sciences, University of Queensland, Brisbane, Australia.
Hum Mol Genet. 2006 Jan 1;15(1):129-42. doi: 10.1093/hmg/ddi434. Epub 2005 Nov 30.
Mutations in the dysferlin (DYSF) and caveolin-3 (CAV3) genes are associated with muscle disease. Dysferlin is mislocalized, by an unknown mechanism, in muscle from patients with mutations in caveolin-3 (Cav-3). To examine the link between Cav-3 mutations and dysferlin mistargeting, we studied their localization at high resolution in muscle fibers, in a model muscle cell line, and upon heterologous expression of dysferlin in muscle cell lines and in wild-type or caveolin-null fibroblasts. Dysferlin shows only partial overlap with Cav-3 on the surface of isolated muscle fibers but co-localizes with Cav-3 in developing transverse (T)-tubules in muscle cell lines. Heterologously expressed dystrophy-associated mutant Cav3R26Q accumulates in the Golgi complex of muscle cell lines or fibroblasts. Cav3R26Q and other Golgi-associated mutants of both Cav-3 (Cav3P104L) and Cav-1 (Cav1P132L) caused a dramatic redistribution of dysferlin to the Golgi complex. Heterologously expressed epitope-tagged dysferlin associates with the plasma membrane in primary fibroblasts and muscle cells. Transport to the cell surface is impaired in the absence of Cav-1 or Cav-3 showing that caveolins are essential for dysferlin association with the PM. These results suggest a functional role for caveolins in a novel post-Golgi trafficking pathway followed by dysferlin.
抗肌萎缩蛋白（DYSF）和小窝蛋白-3（CAV3）基因的突变与肌肉疾病相关。通过未知机制，抗肌萎缩蛋白在小窝蛋白-3（Cav-3）突变患者的肌肉中定位错误。为了研究Cav-3突变与抗肌萎缩蛋白靶向错误之间的联系，我们在肌肉纤维、模型肌肉细胞系以及抗肌萎缩蛋白在肌肉细胞系和野生型或小窝蛋白缺失的成纤维细胞中的异源表达中，以高分辨率研究了它们的定位。在分离的肌肉纤维表面，抗肌萎缩蛋白仅与Cav-3部分重叠，但在肌肉细胞系发育中的横向（T）小管中与Cav-3共定位。异源表达的与营养不良相关的突变体Cav3R26Q在肌肉细胞系或成纤维细胞的高尔基体中积累。Cav3R26Q以及Cav-3（Cav3P104L）和Cav-1（Cav1P132L）的其他与高尔基体相关的突变体导致抗肌萎缩蛋白显著重新分布到高尔基体。异源表达的表位标记抗肌萎缩蛋白在原代成纤维细胞和肌肉细胞中与质膜相关。在没有Cav-1或Cav-3的情况下，向细胞表面的转运受损，表明小窝蛋白对抗肌萎缩蛋白与质膜的结合至关重要。这些结果表明小窝蛋白在抗肌萎缩蛋白随后遵循的新的高尔基体后运输途径中具有功能作用。
