• Physicochemical studies on cardiac myosin of rabbits and dogs have shown that the myosin molecule is highly asymmetric, measuring about 1600 to 1800 A-' long and having a molecular weight of approximately SOO^OO." Electron micrographs of canine cardiac myosin have confirmed this general morphology, although the molecule appears to be several hundred angstroms shorter than the physicochemical ...

Cardiac hypertrophy, induced by pressure overload, leads to a depression in the rate of force development, velocity of shortening, tension-dependent heat generation, and myosin ATPase activity, whereas cardiac hypertrophy, induced by thyroxine administration, leads to an increase in these parameters. These changes have been attributed, in part, to structural changes in myosin. In this study, we...

Autoimmune attack on the heart is linked to host immune responses against cardiac myosin, the most abundant protein in the heart. Although adaptive immunity is required for disease, little is known about innate immune mechanisms. In this study we report that human cardiac myosin (HCM) acted as an endogenous ligand to directly stimulate human TLRs 2 and 8 and to activate human monocytes to relea...

The speed of muscle contraction is related to body size; muscles in larger species contract at slower rates. Since a property the myosin isoform expressed muscle, we investigated how sequence changes range II isoforms enable this rate contraction. We considered 798 sequences from 13 mammalian identify any adaptation increasing mass. identified correlation between mass and divergence for motor d...

Normal canine cardiac myosin exhibits Ca”+ATPase of 0.13 pmol of Pi/min*mg and (K+,EDTA)-ATPase of 0.47 pm01 of Pi/min*mg. Specific activities are similar in myosin preparations from normal left and right ventricles, contrary to the prior report by Wikman-Coffelt et al. (Wikman-Coffelt, J., Fenner, C., Smith, A., and Mason, D. T. (1975) J. Biol. Chem. 250,1257-1262). At 5 weeks after aortic ban...

The dwarf mutant is an autosomal recessive mutation of the mouse which causes a defective development of those anterior pituitary cells responsible for the production of thyroid-stimulating hormone, growth hormone, and prolactin. These mice are thus genetically hypothyroid and provide a model system in which one can investigate the influence of thyroid hormone on the transitions of the myosin h...

We have shown in genetic myopathic hamsters that cardiac myofibrillar ATPase regulation by calcium is altered and that there are shifts in myosin isozyme distribution (V1----V3) suggesting abnormalities in multiple components of the contractile apparatus. To focus more on the regulatory proteins (troponin and tropomyosin), individual proteins of the skeletal and cardiac actomyosin system were r...

Cardiac myosin obtained from atria had a higher Ca2+-activated ATPase activity than did cardiac myosin from ventricles in various species of animals and in humans. The increased specific activity of Ca2+-activated adenosine triphosphatase (ATPase) of atrial myosin appeared to correlate with the level of the activity of ventricular myosin ATPase in the animal, since the same order in ATPase acti...

• Contraction of the heart is dependent upon the proteins myosin and actin. Studies of these contractile proteins have therefore been of interest in the understanding of the normal contractile process, and attempts have been made to relate the diminished cardiac contraction observed in congestive heart failure to alterations in the myosin molecule. Cardiac myosin has been prepared generally by ...

Myosin regulatory light chain (RLC) phosphorylation in skeletal and cardiac muscles modulates Ca(2+)-dependent troponin regulation of contraction. RLC is phosphorylated by a dedicated Ca(2+)-dependent myosin light chain kinase in fast skeletal muscle, where biochemical properties of RLC kinase and phosphatase converge to provide a biochemical memory for RLC phosphorylation and post-activation p...