Metabolism of myosin and life time of myofibrils

Dreyfus, Jean‐Claude; Kruh, Jacques; Schapira, G

doi:10.1042/bj0750574

Cited by 65 publications

(17 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With respect to protein, studies of protein turnover have shown that there is no significant change in protein half-life during left ventricular hypertrophy (19). It is also unlikely, with the relatively slow rate of protein synthesis normally found in muscle (20), that even complete suppression of a hypothetical degradative process could account for net increases of this magnitude.…”

Section: Discussionmentioning

confidence: 99%

Protein Synthetic Activity of Heart Microsomes and Ribosomes during Left Ventricular Hypertrophy in Rabbits

Moroz

1967

Circulation Research

View full text Add to dashboard Cite

Certain aspects of cytoplasmic protein synthesis have been studied during the early stages (0 to 5 days) of left ventricular hypertrophy produced by supravalvular constriction of the ascending aorta in adult rabbits. At 5 days after constriction, cell-free protein synthesis by microsomal preparations from hypertrophied heart muscle was increased, both from free phenylalanine or leucine (50 to 130*), and from phenylalanyl-soluble RNA, both with (70 to 250%) or without (70 to 150SS) polyuridylic acid as artificial messenger. Such increased activity was observed as early as 24 hr, and persisted to 5 days (the limit of the study). Sham preparations also displayed increased activity at 24 hr, which subsided by 5 days. The increased activity could be localized to the microsomal fraction: no differences were found when soluble fractions from normal, sham, and hypertrophied hearts, or from liver, were interchanged. Ribosomes from hypertrophied hearts were no more active than normal ribosomes. Increased yields of microsomal, ribosomal, and soluble RNA were found. It is suggested that the increased protein synthesis occurring in hypertrophy is localized in the microsomes, that soluble factors are not of major significance, and that an increased number of ribosomes (and microsomes) play a major role.ADDITIONAL KEY WORDS thyroid ribosomal RNA transfer enzymes transfer RNA soluble RNA aortic constriction activating enzymes polymerization factors• Hypertrophy is an increase in the mass of a tissue or organ without an increase in the number of cells in that organ. The demand for increased functional tissue is met by an increase in size and organelle content of preexisting cells, without parallel increases in cell number (1-3). This process, characterized by marked increases in tissue ribonucleic acid (RNA) and protein content in the face of minimal or no change in deoxyribonucleic acid (DNA) content, is of particular interest because it provides an opportunity From the Rockefeller University, New York, New York 10021.This investigation was supported by grants from the National Science Foundation and the U. S. Public Health Service.Dr. Moroz is a Fellow of the Helen Hay Whitney Foundation; his present address is Division of Immunochemistry and Allergy Research, Royal Victoria Hospital, Montreal 2, Canada.Accepted for publication August 21, 1967. to study accelerated protein synthesis uncomplicated by significant cellular proliferation. Typically, hypertrophy occurs in muscle, both skeletal and cardiac, and one of the most clear-cut experimental models is provided by the hypertrophy of the left ventricle of the heart subsequent to supravalvular constriction of the ascending aorta in mature animals. Such a preparation has been used to examine changes in the protein synthesizing apparatus of heart muscle during the early stages (0 to 5 days) of the hypertrophic process. A preliminary report of this work has appeared (4).

show abstract

Section: Discussionmentioning

confidence: 99%

Protein Synthetic Activity of Heart Microsomes and Ribosomes during Left Ventricular Hypertrophy in Rabbits

Moroz

1967

Circulation Research

View full text Add to dashboard Cite

show abstract

“…This effect is specific, since the rate of total protein synthesis is relatively unaffected by the addition of creatine. Since myosin is a stable protein in vivo (10,11) and in vitro (12), it is unlikely that degradative processes alone account for the stimulation in the rate of synthesis of myosin heavy-chain in response to creatine.…”

Section: Discussionmentioning

confidence: 99%

Creatine and the Control of Myosin Synthesis in Differentiating Skeletal Muscle

Ingwall¹,

Morales

Stockdale

1972

Proc. Natl. Acad. Sci. U.S.A.

115

View full text Add to dashboard Cite

These experiments provide evidence that creatine, an end product of contraction unique to muscle, is involved in the control of muscle-protein synthesis. Skeletal muscle cells formed both in vitro and in vivo synthesize myosin, heavy chain faster when supplied creatine in vitro. The response is apparent within four hours after addition of creatine to the culture medium, and is dependent on concentration over a range of 10-100 MM creatine. The effect seems to be selective for cellspecific proteins(s), since the rate of total protein synthesis is unaffected.Since hypertrophy and atrophy of skeletal muscle result from increased and decreased muscular activity, one might postulate that a product of muscular activity stimulates contractile protein synthesis. Creatine is a likely candidate for such an effector, since it is a unique product of activity. We have investigated the possibility that creatine functions in this way by manipulating the external concentration of creatine available to differentiating skeletal muscle cells in vitro. We have found that increased concentrations of extracellular creatine selectively stimulates myosin heavy-chain synthesis. MATERIALS AND METHODS Skeletal

show abstract

“…However, experimental support of these hypotheses is lacking, owing chiefly to difficulty in visually identifying newly synthesized contractile proteins with any certainty. Fully formed skeletal muscle is strikingly uniform in appearance, even though isotope studies show the contractile proteins are in a state of dynamic equilibrium, undergoing turnover within the lifetime of the muscle cell (3). To overcome these difficulties the proteins of rat diaphragm were labeled in vitro with 'H-leucine, the soluble proteins were extracted in glycerol, and the distribution of grains over muscle fibers was determined by light and electron microscopic autoradiography.…”

mentioning

confidence: 99%