Cardiac Muscle Protein Research Articles

Biochemical and Immunological Heterogeneity of 100 Å Filament Subunits from Different Chick Cell Types

The 100 A filament subunit proteins of chick fibroblasts and gizzard smooth muscle were compared. These proteins are major cellular components in these cell types, constituting up to 98% of the cell's total protein. Co-electrophoresis of cytoskeletal fractions of fibroblasts and smooth muscle revealed that the subunit proteins differed in their molecular weights: 58,000 daltons in fibroblasts and 55,000 daltons in smooth muscle. Cytoskeletal fractions from other cell types were also examined: chondroblasts contained the 58,000 dalton subunit, and cytoskeletons of skeletal muscle and cardiac muscle contained both 55,000 and 58,000 dalton proteins. Chick skin and rat kangaroo Pt K2 cells had more complex subunit patterns which resemble prekeratin. The peptide patterns resulting from proteolytic digestion of the 58,000 dalton protein of fibroblasts, the 55,000 dalton proteins of smooth muscle and PT K2 cells, and chick brain tubulin differed from one another. Two-dimensional electrophoresis of reconstituted gizzard smooth muscle 100 A filaments showed the 55,000 dalton subunit to be composed of two major components, differing in their isoelectric points. Antibodies prepared against electrophoretically purified 55,000 dalton subunit protein reacted in immunodiffusion against the original smooth muscle antigen and cytoskeletal fractions from skeletal and cardiac muscle, but not from fibroblasts, brain, liver, or skin cells. A specific antigenic determinant common to subunit proteins in smooth, skeletal, and cardiac muscle, is therefore indicated. A previously described antibody against fibroblast subunit protein reacted weakly against smooth muscle filament protein in immunodiffusion revealing the presence of a common antigenic determinant between the two subunit proteins. These data demonstrate striking antigenic and primary structural differences in 100 A filament subunits from even such closely related cell types as fibroblasts on the one hand and muscle cells on the other.

Age related changes in muscle protein degradation

In vitro autolytic degradation of sarcoplasmic proteins in red, white and cardiac muscles increases with advance in age and with increase in temperature, the rate varying with age. Higher activity is seen in the alkaline range in all age groups. Ca 2+ activated proteolytic activity also increases with advance in age.

Cooperative interactions between the contractile proteins of cardiac and skeletal muscle

The calcium activation of the ATPase (ATP phosphohydrolase, EC 3.6.1.3) activity of cardiac actomyosin reconstituted from bovine cardiac myosin and a complex of actin-tropomyosin-troponin extracted from bovine cardiac muscle at 37°C was studied and compared with similar proteins from rabbit fast skeletal muscle. The proteins of the actin complex were identified by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. Half-maximal activation of the cardiac actomyosin was seen at a calcium concentration of 1.2 ± 0.002 (S.E. of mean) μM. A hybridized reconstituted actomyosin made with cardiac myosin and the actin-tropomyosin-troponin complex extracted from rabbit skeletal muscle was also activated by calcium but the half-maximal value was shifted to 0.65 ± 0.02 (S.E. of mean) μM Ca 2+. Homologous rabbit skeletal actomyosin showed half-maximal activation at 0.90 ± 0.01 (S.E. of mean) μM Ca 2+ and the value for a hybridized actomyosin made with rabbit skeletal myosin and the actin-complex from cardiac muscle was found at 1.4 ± 0.03 (S.E. of mean) μM Ca 2+ concentration. Kinetic analysis of the Ca 2+-activated ATPase activity of reconstituted bovine cardiac actomyosin indicated some degree of cooperativity with respect to calcium. Double reciprocal plots of reconstituted actomyosins made with bovine cardiac actin complex were curvilinear and significantly different than those of reconstituted actomyosins made with the rabbit fast skeletal actin complex. The Ca 2+-dependent cooperativity was of a mixed type as determined from Hill plots for homologous reconstituted bovine cardiac and rabbit fast skeletal actomyosin. The results show that cooperative interactions in reconstituted actomyosins were greater when the actin-tropomyosin-troponin complex was derived from cardiac than skeletal muscle.

Biochemical aspects of cardiac muscle differentiation. Possible control of deoxyribonucleic acid synthesis and cell differentiation by adrenergic innervation and cyclic adenosine 3':5'-monophosphate.

A single injection of either isoproternol or N6, O2'-dibutyryl adenosine 3':5'-monophosphate (dibutyryl cyclic AMP) results in an inhibition in the rate of [3H]thymidine incorporation into DNA of differentiating cardiac muscle of the neonatal rat. This inhibition is not due to substantially altered cellular uptake or catabolism of [3H]thymidine. Inhibition of [3H]thymidine incorporation by isoproterenol or dibutyryl cyclic AMP is potentiated by theophylline. Maximal inhibition (95%) is observed 24 h after administration of isoproterenol, and the rate of incorporation returns to a value 80% of control by 72 h. Norepinephrine also inhibits [3H]thymidine incorporation whereas cyclic GMP, N2, 02-Dibutyryl guanosine 3':5'-monophosphate (dibutyryl cyclic GMP), and phenylephrine have little effect. Equilibrium sedimentation analysis of cardiac muscle DNA in neutral and alkaline cesium chloride gradients using bromodeoxyuridine as a density label indicate that isoproterenol and dibutyryl cyclic AMP inhibit [3H]thymidine incorporation into DNA that is replicating semiconservatively. Administration of isoproterenol or dibutyryl cyclic AMP to neonatal rats inhibits by approximately 60% the incorporation of [3H]thymidine into DNA of tissue slices of cardiac muscle prepared 16 h later. [3H]Thymidine incorporation into DNA of tissue slices is into chains that were growing in vivo. This incorporation is linear for at least 4 h of incubation and is inhibited by isoproterenol and dibutyryl cyclic AMP. Inhibition is not due to altered cellular uptake of [3H]thymidine nor is it due to a cytotoxic action. Several other compounds which elevate intracellular levels of cyclic AMP (epinephrine, norepinephrine, glucagon, and prostaglandin E1) also inhibit [3H]thymidine incorporation into DNA or cardiac muscle tissue slices. Cyclic GMP, dibutyryl cyclic GMP, sodium butyrate, and phenylephrine have little effect. Isoproterenol administered together with theophylline to neonatal rats signficantly stimulates the in corporation of [3H]phenylalanine into total cardiac muscle protein and into myosin. This enhanced incorporation may be due in part to an increase in the cellular uptake of [3H]phenylalanine. DNA synthesis decreases progressively in differentiating cardiac muscle of the rat during postnatal development and essentially ceases by the middle of the third week (Claycomb, W. C. (1975) J. Biol. Chem. 250, 3229-3235). In reviewing the literature it was found that this decline in synthetic activity correlates temporally with a progressive increase in tissue concentrations of norepinephrine and cyclic AMP and with the anatomical and physiological development of the adrenergic nerves in this tissue. Because of these facts and data presented in this report it is proposed that cell proliferation and cell differentiation in cardiac muscle may be controlled by adrenergic innervation with norepinephrine and cyclic AMP serving as chemical mediators.

Phosphorylation of the active, A1 component of cholera toxin by protein kinase

Cholera toxin, an activator of adenylate cyclase in a wide variety of cells, is a substrate for the phosphotransferase reaction catalyzed by purified cyclic adenosine 5'-monophosphate dependent bovine cardiac muscle protein kinase and the protein associated with human erythrocyte membranes. Phosphorylation occurs when the toxin is dissociated with 5-20 mM dithiothreitol and is restricted to the A1 or "adenylate cyclase activating" subunit of the toxin.

Effects of noncarbohydrate substrates on protein synthesis in muscle.

Effects of noncarbohydrate substrates on protein synthesis in muscle.

Protein synthesis by rat cardiac muscle myofibkils

The present study is an attempt to elucidate the role of cardiac muscle myofibrils in protein synthesis. Pulse labelling in vivo shows that the fraction containing myofibrils is a major site of amino acid incorporation into protein. Myofibrils and myofibrillar ribosomes incorporate labelled amino acids into protein when incubated in a conventional medium used to demonstrate cell-free protein synthesis. Evidences are presented to establish that the protein synthesis is genuine. Ribosomes derived from myofibrils show a nearly 4-fold increase in specific activity in comparison with myofibrils. Neither cycloheximide nor chloramphenicol inhibits in vitro amino acid incorporation by myofibrils or by ribosomes derived from them. In contrast, in vivo amino acid incorporation into protein of cardiac muscle and its subcellular fractions is nearly completely inhibited by cycloheximide. Amino acid incorporation by isolated myofibrils and by myofibrillar ribosomes is not inhibited by ribonuclease. The in vitro amino acid incorporation by myofibrils does not appear to depend on factors present in the cell sap. The results suggest extensive and independent protein synthesis by myofibrils, with myofibrillar ribosomes as the functional units.

Protein synthesis rate in the newborn lamb.

Fractional protein synthesis rate was measured in the liver, and skeletal and cardiac muscles of newborn lambs, 2–5 days of, age. The contant infusion method was used and <sup>14</sup>C-labelled leucine was given intravenously for 5 h. Blood samples were taken each hour and analysed for plasma leucine and specific activity; at the end of the experiment free (S<sub>i</sub>) and protein-bound (S<sub>B</sub>) leucine specific activity was measured in each organ. The calculated results indicated that more than 100% of the liver proteins were synthetised in a day in the newborn lamb, and that the synthesis rate of cardiac and skeletal muscle proteins were 35 and 25% day-1, respectively. Total leucine flux was 900 μmol/kg/day.

Protein synthesis by red and white muscle in vitro: effect of insulin and animal age.

ARTICLESProtein synthesis by red and white muscle in vitro: effect of insulin and animal ageFA ShortFA ShortPublished Online:01 Jul 1969https://doi.org/10.1152/ajplegacy.1969.217.1.307MoreSectionsPDF (578 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByThe in vivo study of cardiac and skeletal muscle protein turnoverDiabetes / Metabolism Reviews, Vol. 5, No. 2Contrast Media in the Cardiovascular SystemDie Regulation der Proteinsynthese am normalen Herzen und unter pathologischen BedingungenContractile Function as a Determinant of Muscle GrowthEffects of diabetes on protein synthesis in fast- and slow-twitch rat skeletal muscleK. E. Flaim, M. E. Copenhaver, and L. S. Jefferson1 July 1980 | American Journal of Physiology-Endocrinology and Metabolism, Vol. 239, No. 1Relationship between Milk Yield and Mammary Gland Development in MiceJournal of Dairy Science, Vol. 61, No. 6Evaluation of RNA polymerase activities in nuclei isolated from slow and fast skeletal musclesExperimental Cell Research, Vol. 108, No. 2Relative in vivo and in vitro incorporation of labelled leucine into pig liver and muscle proteinsInternational Journal of Biochemistry, Vol. 8, No. 4Age-related changes in course of restitution of secretory material in rat submandibular gland stimulated with isoproterenolExperimental Gerontology, Vol. 12, No. 3-4Protein synthesis by ribosomes from normal and denervated red and white muscleExperimental Neurology, Vol. 51, No. 3Serum insulin and somatomedin levels in the tumour-bearing ratEuropean Journal of Cancer (1965), Vol. 11, No. 10Protein synthesizing activity of chicken liver and muscleInternational Journal of Biochemistry, Vol. 6, No. 6Skeletal muscle leucine incorporation and testosterone uptake in exercised guinea pigsEuropean Journal of Applied Physiology and Occupational Physiology, Vol. 34, No. 1Effect of Streptozotocin Diabetes and Insulin Treatment on the Rate of Protein Synthesis in Tissues of the Rat in VivoJournal of Biological Chemistry, Vol. 249, No. 14In vivo studies on the effect of garlic oil in miceToxicology, Vol. 1, No. 4Incorporation of 14C leucine into the fat body of the cockroach Periplaneta americana during oöcyte developmentJournal of Insect Physiology, Vol. 19, No. 11Protein synthesis by rat cardiac muscle myofibkilsBiochimica et Biophysica Acta (BBA) - Nucleic Acids and Protein Synthesis, Vol. 312, No. 2Effect of garlic oil on incorporation of amino acids into proteins of Culex pipiens quinquefasciatus say larvaeChemico-Biological Interactions, Vol. 6, No. 3Incorporation of leucine-14C into proteins of the placenta and liver of miceAmerican Journal of Obstetrics and Gynecology, Vol. 114, No. 1Depletion of proteins of phasic and tonic muscles in tumour-bearing ratsEuropean Journal of Cancer (1965), Vol. 7, No. 1Die chronischen Effekte körperlichen Trainings auf den StoffwechselThe Role of Skeletal and Cardiac Muscle in the Regulation of Protein Metabolism More from this issue > Volume 217Issue 1July 1969Pages 307-309 Copyright & PermissionsCopyright © 1969 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1969.217.1.307PubMed5785893History Published online 1 July 1969 Published in print 1 July 1969 Metrics

Contractile proteins of cardiac muscle.

Contractile proteins of cardiac muscle.

The effect of strophanthin-K on the activity of the myocardial sulfhydryl groups

Theissue deals with the effect of strophanthin-K on the function of the isolated frogheartin conditions of selective blocking of sulfhydryl groups of cardiac muscle proteins by means of cadmium chloride. In such conditions strophanthin restored the cardiac contractions in all the experiments. The effect of urea and ATP was tested during sharp depression of the cardiac activity, caused by prolonged strophanthin perfusion. As a rule urea gave no effect, whereas ATP completely restored the amplitude of cardiac contractions. The ATP sensitivity lost by the cardiac muscle, may be restored by a brief action of strophanthin on the cardiac muscle. A suggestion was put forward that an important role in the mechanism of strophanthin effect on the contractility and the ATP activity of the cardiac muscle is played by an increased sulfhydryl group activity.