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Trifluoperazine, a calmodulin antagonist, inhibits muscle cell fusion

D Bar-Sagi, J Prives

    The Journal of Cell Biology
    |November 1, 1983
    PubMed

    Insights

    Trifluoperazine (TFP) inhibits chick skeletal myoblast fusion by targeting calmodulin. This calmodulin antagonism disrupts myoblast alignment but does not affect acetylcholine receptor expression, suggesting calmodulin’s role in muscle cell fusion regulation.

    Area of Science:

    • Cell Biology
    • Muscle Development
    • Biochemistry

    Background:

    • Myoblast fusion is crucial for skeletal muscle formation.
    • Calmodulin is a key calcium-binding protein involved in various cellular processes.
    • The precise role of calmodulin in myoblast fusion remains to be fully elucidated.

    Purpose of the Study:

    • To investigate the effect of trifluoperazine (TFP), a calmodulin antagonist, on chick skeletal myoblast fusion.
    • To explore the involvement of calmodulin in the regulation of myoblast fusion and differentiation.

    Main Methods:

    • Primary culture of chick skeletal myoblasts.
    • Treatment with calmodulin antagonists, including TFP, chlorpromazine, W7, and W5.
    • Assessment of myoblast fusion, alignment, and acetylcholine receptor expression.
    • Immunofluorescence staining for calmodulin distribution.

    Main Results:

    • Trifluoperazine (TFP) significantly inhibited myoblast fusion in a dose-dependent manner.
    • Other calmodulin antagonists also inhibited fusion, correlating with their calmodulin-binding affinity.
    • TFP-induced fusion inhibition was reversible upon TFP removal and partially reversed by Ca2+ ionophore A23187.
    • Calmodulin redistribution was observed during myoblast fusion, suggesting its dynamic role.

    Conclusions:

    • Calmodulin plays a regulatory role in the process of myoblast fusion.
    • Calmodulin antagonism disrupts myoblast alignment but not acetylcholine receptor expression.
    • These findings highlight calmodulin as a potential target for modulating muscle development.

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