Cardiomyopathies due to mutations in human β-cardiac myosin are a significant cause of heart failure, sudden death, and arrhythmia. To understand the underlying molecular basis of changes in the contractile system's force production due to such mutations and search for potential drugs that restore force generation, an in vitro assay is necessary to evaluate cardiac myosin's ensemble force using...

BALB/c mice develop autoimmune myocarditis after immunization with mouse cardiac myosin, whereas C57B/6 mice do not. To define the immunogenicity and pathogenicity of cardiac myosin in BALB/c mice, we immunized mice with different forms of cardiac myosin. These studies demonstrate the discordance of immunogenicity and pathogenicity of myosin heavy chains. The cardiac alpha-myosin heavy chains o...

Heart tissue destruction in chronic Chagas' disease cardiomyopathy (CCC) may be caused by autoimmune recognition of heart tissue by a mononuclear cell infiltrate decades after Trypanosoma cruzi infection. Indirect evidence suggests there is molecular mimicry between T. cruzi and heart tissue. In murine models of CCC, antibodies and CD4+ T cells recognize myosin, the major heart protein. We rece...

Previous studies have suggested that the molecular and enzymatic parameters of cardiac myosin are quite similar to those of its skeletal counterpart (I). Thus, the weight average molecular weight, iWW, weight intrinsic viscosity, [v], and intrinsic sedimentation constant, siO, W, are comparable with the corresponding data on the skeletal protein (2). Also, the enzymatic adenosine triphosphatase...

Cardiac function was impaired in hearts from hypophysectomized rats. Corresponding to the decrease in performance, myosin from the hearts of these rats exhibited a decreased Ca -activated ATPase activity. Myosin ATPase activated by K or NH4 + was not different in any of the preparations studied. The decreased Ca -activated ATPase was observed in cardiac myosin but not in red or white skeletal m...

We used light scattering and ultracentrifugation to study the binding ratio of myosin and actin from normal and failing dog hearts and to determine the effect of temperature and adenosine triphosphate (ATP) on the binding. For comparison, similar studies were done on myosin and actin from rabbit skeletal muscle. We found a higher combining ratio, by weight, for cardiac myosin and actin (4.8 : 1...

Myosin motors are the fundamental force-generating elements of muscle contraction. Variation in the human β-cardiac myosin heavy chain gene (MYH7) can lead to hypertrophic cardiomyopathy (HCM), a heritable disease characterized by cardiac hypertrophy, heart failure, and sudden cardiac death. How specific myosin variants alter motor function or clinical expression of disease remains incompletely...

Contraction of the heart results from interaction of the myosin and actin filaments. Cardiac myosin filaments consist of the molecular motor myosin II, the sarcomeric template protein, titin, and the cardiac modulatory protein, myosin binding protein C (MyBP-C). Inherited hypertrophic cardiomyopathy (HCM) is a disease caused mainly by mutations in these proteins. The structure of cardiac myosin...

Although diuretics have been clinically shown to reduce cardiovascular morbidity and mortality, the effects of diuretics on cardiac hypertrophy are poorly understood. In this study, we examined the molecular effects of diuretics on hypertensive cardiac hypertrophy. Spontaneously hypertensive rats (SHR) were given p.o. M17055 (a novel "high ceiling" diuretic) 1.25, 2.5 or 5 mg/kg/day, furosemide...

Hypertrophic cardiomyopathy is a multigenetic cardiac disease with autosomal dominant pattern of inheritance and incomplete penetrance, with the exclusion of those cases caused by mutations in the mitochondrial genome. The disease is usually caused by mutations in several sarcomeric contractile protein genes. Mutations have been found in four genes that encode components of the thick filament: ...