Functional effects of congenital myopathy-related mutations in gamma-tropomyosin gene

► Molecular mechanism of tropomyosin-related congenital myopathies is proposed. ► Tropomyosin mutants affect assembly and regulation of actin thin filaments. ► A decrease of Ca-dependent activation of actomyosin is common in all myopathies. ► Ca- and myosin-induced activation is required for normal actin motility. ► Mutations located in the central tropomyosin region have the most severe effects.