Desmin degradation and Ca2+-dependent proteolysis during myoblast fusion

N Elamrani, J J Brustis, N Dourdin, Denis Pierre Balcerzak, S Poussard, P Cottin, A Ducastaing

    Research output: Contribution to journalArticle

    19 Citations (Scopus)

    Abstract

    It has already been reported that, in vitro, intermediate filaments such as desmin and vimentin are very susceptible to proteolysis by calpains (Ca2+-activated cysteine proteinases). On the other hand, desmin and m-calpain are both present at the onset of myoblast fusion and throughout this phenomenon. Based on these observations, the aim of this study was to demonstrate, with cultured rat myoblasts, that the amount of desmin decreased significantly as multinucleated myotubes were formed. Using immunoblot analysis, it has been shown that the desmin concentration decreased 41% as myoblasts fuse. Moreover, under conditions which stimulate myoblast fusion, desmin concentration was reduced by 21% compared to the control culture. Under our experimental conditions, which lead to a reduced desmin level, the amount of m-calpain was increased about three-fold. These results suggested that m-calpain could be involved in myoblast fusion via desmin cleavage. This hypothesis was confirmed by the results obtained after calpeptin treatment. In the presence of this cell-penetrating inhibitor of calpains, desmin seems not-to be degraded. Taking into account the observations obtained after different hydrolysis assays and as compared to those observed-on cultured cells, it seems conceivable that m-calpain would be able to initiate desmin cleavage leading to the formation of-proteolytic fragments which should be immediately degraded.

    Original languageEnglish
    Pages (from-to)177-183
    Number of pages7
    JournalBiology of the Cell
    Volume85
    Issue number2-3
    Publication statusPublished - 1995

    Keywords

    • desmin
    • fusion
    • m-calpain
    • myoblast culture
    • INTERMEDIATE FILAMENT PROTEINS
    • TRANSFORMING GROWTH-FACTOR
    • CHICKEN SKELETAL-MUSCLE
    • MYOGENIC DIFFERENTIATION
    • Z-DISC
    • EXPRESSION
    • VIMENTIN
    • CELLS
    • PURIFICATION
    • PROTEASE

    Cite this

    Elamrani, N., Brustis, J. J., Dourdin, N., Balcerzak, D. P., Poussard, S., Cottin, P., & Ducastaing, A. (1995). Desmin degradation and Ca2+-dependent proteolysis during myoblast fusion. Biology of the Cell, 85(2-3), 177-183.