Association of syncoilin and desmin: linking intermediate filament proteins to the dystrophin-associated protein complex

• Published in: The Journal of biological chemistry 2002-02, Vol.277 (5), p.3433-3439
• Main Authors: Poon, Ellen, Howman, Emily V, Newey, Sarah E, Davies, Kay E
• Format: Article
• Language: English
• Subjects: Animals; Cell Line; Chlorocebus aethiops; Cloning, Molecular; COS Cells; Desmin - chemistry; Desmin - metabolism; DNA Primers; Dystrophin - metabolism; Gene Library; Genetic Vectors; Intermediate Filament Proteins - chemistry; Intermediate Filament Proteins - metabolism; Mice; Mice, Inbred C57BL; Molecular Sequence Data; Muscle Proteins - chemistry; Muscle Proteins - metabolism; Muscle, Skeletal - metabolism; Polymerase Chain Reaction; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; Saccharomyces cerevisiae - genetics; Transfection
• ISSN: 0021-9258
• DOI: 10.1074/jbc.M105273200

We recently identified a novel protein called syncoilin, a putative intermediate filament protein that interacts with alpha-dystrobrevin, a member of the dystrophin-associated protein complex. Syncoilin is found at the neuromuscular junction, sarcolemma, and Z-lines and is thought to be important for muscle fiber integrity. Based on the similar protein structure and cellular localization of syncoilin and desmin, we proposed that these proteins interact in vivo. The data presented confirm an interaction between syncoilin and desmin and demonstrate their co-localization in skeletal muscle. Intriguingly, whereas these proteins interact, COS-7 cell expression studies show that desmin and syncoilin do not assemble into heterofilaments. Furthermore, fractionation assay and immunofluorescence study of H2K myoblasts and myotubes suggest that, unlike typical intermediate filament proteins, syncoilin does not participate in filament formation with any protein. However, it is possible that syncoilin is involved in the anchoring of the desmin intermediate filament network at the sarcolemma and the neuromuscular junction. This interaction is likely to be important for maintaining muscle fiber integrity and may also link the dystrophin-associated protein complex to the cytoskeleton. The dysfunction or absence of syncoilin may result in the disruption of the intermediate filament network leading to muscle necrosis. Syncoilin is therefore an ideal candidate gene for muscular dystrophies and desmin-related myopathies.