The effect of thyroid state on the activity of myosin adenosinetriphosphatase (ATPase) was examined in the rat and the rabbit. Cardiac myosin from thyroxinetreated rabbits showed enzymatic properties characterized by high Ca-activated ATPase activity, low activating energy, lower rate of inactivation at alkaline pH, and no activation by Af-ethylmaleimide compared with the same properties in the...

The group A streptococcal M protein is an important virulence determinant eliciting protective and autoimmune responses against the streptococcus and cardiac myosin, respectively. In this report, the major human cardiac myosin-cross-reactive T-cell epitopes of M5 protein are identified and localized to myosin-like repeats within the M5 molecule. BALB/c mice were immunized with human cardiac myo...

The effect of thyroid state on the activity of myosin adenosinetriphosphatase (ATPase) was examined in the rat and the rabbit. Cardiac myosin from thyroxine-treated rabbits showed enzymatic properties characterized by high Ca2plus-activated ATPase activity, low activation energy, lower rate of inactivation at alkaline pH, and no activation by N-ethylmaleimide compared with the same properties i...

To test for possible differences in local conformation and S1 flexibility, bovine cardiac and rabbit skeletal myosins were labeled with a fluorophore (1,5-IAEDANS) and a spin label having iodoacetamide reactivity. The marked activation of the Ca2+-ATPase (6- to 8-fold) and inhibition of the K+ (EDTA)-ATPase (80-90%) by both labels indicated specific labeling of the fast-reacting thiols (SH1) of...

Human myosin heavy chains are encoded by a multigene family consisting of at least 10 members. A gene-specific oligonucleotide has been used to isolate the human beta myosin heavy chain gene from a group of twelve nonoverlapping genomic clones. We have shown that this gene (which is expressed in both cardiac and skeletal muscle) is located 3.6kb upstream of the alpha cardiac myosin gene. We fin...

introduction: extracellular matrix (ecm) components significantly influence the growth characteristics of cell, development of spontaneous contractile activity, andmorphologic differentiation. the present study evaluates the effect of ecm ongenotypic and physiologic characteristics of cardiomyocytes derived from embryonic stem (es) cells. material and methods: embryoid bodies derived from mouse...

Examination of the ATPase activities of rabbit cardiac, rabbit red skeletal and rabbit white skeletal muscle myosins has demonstrated the existence of two types of myosin. One type, characterized by the higher ATPase activity, is present in white skeletal muscle; the other is found in red skeletal and cardiac muscle. The differences between myosin preparations could not be attributed to varying...

Myosin is an essential driver of cardiac and skeletal muscle function. Multiple mutations identified in β-cardiac/skeletal slow myosin heavy chain (MYH7) fast 2A (MYH2), cause a group human diseases termed myosinopathies1. Over 90% these are found the filament-forming region coiled-coil tail, also known as light meromyosin (LMM). A mutation to proline residue or deletion single-residue common m...

The extents of superprecipitation and contractile protein contents of myosin B in the myocardium and conduction system were compared. The extents of superprecipitation of myosin B of the two types of cardiac muscle were similar, but the onset of the superprecipitation reaction of myosin B from the conduction system was delayed and the clearing phase of the reaction was prolonged. On sodium dode...

UNC-45 is a UCS (UNC-45/CRO1/She4P) class chaperone necessary for myosin folding and/or accumulation, but its requirement for maintaining cardiac contractility has not been explored. Given the prevalence of myosin mutations in eliciting cardiomyopathy, chaperones like UNC-45 are likely to be equally critical in provoking or modulating myosin-associated cardiomyopathy. Here, we used the Drosophi...