Aberrant dysferlin trafficking in cells lacking caveolin or expressing dystrophy mutants of caveolin-3

Hum Mol Genet. 2006 Jan 1;15(1):129-42. doi: 10.1093/hmg/ddi434. Epub 2005 Nov 30.

Abstract

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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caveolin 3 / deficiency*
  • Caveolin 3 / genetics*
  • Cell Membrane / metabolism*
  • Cells, Cultured
  • Dysferlin
  • Female
  • Golgi Apparatus / metabolism
  • Immunoblotting
  • Membrane Proteins / physiology*
  • Mice
  • Microscopy, Fluorescence
  • Microscopy, Immunoelectron
  • Muscle Fibers, Skeletal / metabolism*
  • Muscle Fibers, Skeletal / physiology
  • Muscle Fibers, Skeletal / ultrastructure
  • Mutation / genetics
  • Protein Transport / physiology

Substances

  • Cav3 protein, mouse
  • Caveolin 3
  • Dysf protein, mouse
  • Dysferlin
  • Membrane Proteins