We examined the expression of the cytoskeletal proteins dystrophin and β- spectrin on vacuolar boundaries in vacuolar myopathies. We also localized utrophin, a dystrophin homologue, and laminin, which served as a marker for the basal lamina. Four types of vacuoles were identified. Type 1 vacuoles, found in all diseases, were lined by laminin, dystrophin, and β-spectrin and arose from infoldings of the basal lamina and sarcolemma into splitting or branching fibers. Type 2 vacuoles were lined by dystrophin and β-spectrin and were most common in adult acid maltase deficiency, chloroquine myopathy, and periodic paralysis. Traces of utrophin were also noted on the boundaries of some type 2 vacuoles, but only in those fibers that also expressed utrophin on their surface membrane. Type 3 vacuoles were lined by small patches of dystrophin and β-spectrin and occurred in any vacuolar myopathy. Type 4 vacuoles were unlined by any of the above antigens and were most common in infantile acid maltase deficiency and in the nonlysosomal glycogenoses. Immunoelectron microscopy confirmed the dystrophin label on vacuolar boundaries but revealed no reaction product on any other membranous component within the muscle fiber. We conclude that dystrophin and β- spectrin provide cytoskeletal support for a species of membrane-bound vacuoles in diverse myopathies.
|Original language||English (US)|
|Number of pages||9|
|Journal||American Journal of Pathology|
|State||Published - 1993|
ASJC Scopus subject areas
- Pathology and Forensic Medicine