Association between the muscle-specific proteins desmin and caveolin-3 in muscle cells

The muscle-specific intermediate filament protein desmin is expressed in mononucleated myoblasts and in differentiated myotubes. Desmin has been shown to associate with the sarcolemma in specific structures, such as neuromuscular junctions and the dystrophin-associated protein complex. Since these are specialized membrane regions, the study of a possible association between desmin and liquid-ordered membrane microdomains is of particular interest. We have carried out an analysis of the association between desmin and the muscle-specific protein caveolin-3, a major component of caveolar microdomains. Our results demonstrate that (1) desmin precisely co-localizes with caveolin-3 in myoblasts and multinucleated myotubes, (2) caveolin-3 is up-regulated during in vitro chick muscle development, (3) desmin is detectable in caveolae-enriched membrane fractions prepared from skeletal muscle, and (4) caveolin-3 co-immunoprecipitates with desmin. We have thus shown, for the first time, an association between the intermediate filament protein desmin and caveolin-3 in myogenic cells.