scholarly journals Commentary: Effect of Skeletal Muscle Native Tropomyosin on the Interaction of Amoeba Actin with Heavy Meromyosin

2016 ◽  
Vol 7 ◽  
Author(s):  
Joseph M. Chalovich ◽  
Dylan Johnson
Keyword(s):  
Skeletal Muscle ◽  
Heavy Meromyosin

Inhibition by Palmitoyl CoA of EDTA- and Mg2+-ATPase of Heavy Meromyosin from Rabbit Skeletal Muscle

1981 ◽  
Vol 90 (3) ◽  
pp. 757-763 ◽  
Author(s):  
Akiko FUJIWARA ◽  
Hisao FUJISAKI ◽  
Hiroshi ASAI ◽  
Ikuo YASUMASU
Keyword(s):  
Skeletal Muscle ◽  
Rabbit Skeletal Muscle ◽  
Heavy Meromyosin

scholarly journals Myosin light-chain phosphatase

1976 ◽  
Vol 157 (3) ◽  
pp. 687-697 ◽  
Author(s):  
M Morgan ◽  
S V Perry ◽  
J Ottaway
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Sodium Dodecyl Sulphate ◽  
Myosin Light Chain Kinase ◽  
Adenosine Triphosphatase ◽  
Myosin Light Chain ◽  
Sodium Dodecyl ◽  
Affinity Column ◽  
Heavy Meromyosin ◽  
Myosin Light Chain Phosphatase

1. A method for the isolation of a new enzyme, myosin light-chain phosphatase, from rabbit white skeletal muscle by using a Sepharose-phosphorylated myosin light-chain affinity column is described. 2. The enzyme migrated as a single component on electrophoresis in sodium dodecyl sulphate/polyacrylamide gel at pH7.0, with apparent mol.wt. 70000. 3. The enzyme was highly specific for the phosphorylated P-light chain of myosin, had pH optima at 6.5 and 8.0 and was not inhibited by NaF. 4. A Ca2+-sensitive ‘ATPase’ (adenosine triphosphatase) system consisting of myosin light-chain kinase, myosin light-chain phosphatase and the P-light chain is described. 5. Evidence is presented for a phosphoryl exchange between Pi, phosphorylated P-light chain and myosin light-chain phosphatase. 6. Heavy meromyosin prepared by chymotryptic digestion can be phosphorylated by myosin light-chain kinase. 7. The ATPase activities of myosin and heavy meromyosin, in the presence and absence of F-actin, were not significantly changed (+/- 10%) by phosphorylation of the P-light chain.

scholarly journals Action of Dinitrophenyl Amino Acids on Skeletal Muscle Proteins

1969 ◽  
Vol 22 (1) ◽  
pp. 205
Author(s):  
RW Burley ◽  
Jean P Robertson
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Equilibrium Dialysis ◽  
Total Absorption ◽  
Muscle Proteins ◽  
Heavy Meromyosin ◽  
Skeletal Muscle Myosin ◽  
Skeletal Muscle Proteins ◽  
Sulphydryl Groups ◽  
Muscle Myosin

Isotherms for the total absorption ofbis(2,4-dinitrophenyl)-L-lysine (bis-DNP-lysine) by rabbit skeletal muscle myosin and heavy meromyosin whose sulphydryl groups had been progressively blocked with p-chloromercuribenzoate were measured by equilibrium dialysis in Tris buffers containing potassium chloride.

scholarly journals Degradation of smooth-muscle myosin by trypsin-like serine proteinases.

1982 ◽  
Vol 201 (2) ◽  
pp. 267-278 ◽  
Author(s):  
J Kay ◽  
R F Siemankowski ◽  
L M Siemankowski ◽  
D E Goll
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Atpase Activity ◽  
Heavy Chain ◽  
Light Chain ◽  
Regulatory Light Chain ◽  
Smooth Muscle Myosin ◽  
Heavy Meromyosin ◽  
Bovine Trypsin ◽  
Muscle Myosin

1. Hydrolysis of the myosins from smooth and from skeletal muscle by a rat trypsin-like serine proteinase and by bovine trypsin at pH 7 is compared. 2. Proteolysis of the heavy chains of both myosins by the rat enzyme proceeds at rates approx. 20 times faster than those obtained with bovine trypsin. Whereas cleavage of skeletal-muscle myosin heavy chain by both enzymes results in the generation of conventional products i.e. heavy meromyosin and light meromyosin, the heavy chain of smooth-muscle myosin is degraded into a fragment of mol. wt. 150000. This is dissimilar from heavy meromyosin and cannot be converted into heavy meromyosin. It is shown that proteolysis of the heavy chain takes place in the head region. 3. The ‘regulatory’ light chain (20kDa) of smooth-muscle myosin is degraded very rapidly by the rat proteinase. 4. The ability of smooth-muscle myosin to have its ATPase activity activated by actin in the presence of a crude tropomyosin fraction on introduction of Ca2+ is diminished progressively during exposure to the rat proteinase. The rate of loss of the Ca2+-activated actomyosin ATPase activity is very similar to the rate observed for proteolysis of the heavy chain and 3-4 times slower than the rate of removal of the so-called ‘regulatory’ light chain. 5. The significance of these findings in terms of the functional organization of the smooth muscle myosin molecule is discussed. 6. Since the degraded myosin obtained after exposure to very small amounts of the rat proteinase is no longer able to respond to Ca2+, i.e. the functional activity of the molecule has been removed, the implications of a similar type of proteolysis operating in vivo are considered for myofibrillar protein turnover in general, but particularly with regard to the initiation of myosin degradation, which is known to take place outside the lysosome (i.e. at neutral pH).

scholarly journals Association of microinjected myosin and its subfragments with myofibrils in living muscle cells.

1988 ◽  
Vol 107 (6) ◽  
pp. 2213-2221 ◽  
Author(s):  
C S Johnson ◽  
N M McKenna ◽  
Y Wang
Keyword(s):  
Skeletal Muscle ◽  
Similar Pattern ◽  
Fluorescence Recovery After Photobleaching ◽  
Muscle Cells ◽  
Heavy Meromyosin ◽  
Ionic Condition ◽  
Skeletal Muscle Myosin ◽  
Fluorescent Heavy Meromyosin ◽  
Muscle Myosin ◽  
Low Solubility

Purified skeletal muscle myosin was labeled with iodoacetamidofluorescein and microinjected into cultured chick myotubes. The fluorescent myosin analogue became incorporated within 10-15 min after injection, into either periodic (mean periodicity = 2.23 +/- 0.02 micron) bands or apparently continuous fibrillar structures. Comparison of rhodamine-labeled alpha-actinin with coinjected fluorescein-labeled myosin suggested that myosin fluorescence was localized at the A-bands of myofibrils. In addition, close examination of the fluorescent myosin bands indicated that they were composed of two fluorescent bars separated by a nonfluorescent line that corresponded to the H-zone. Once incorporated, the myosin underwent a relatively slow exchange along myofibrils as indicated by fluorescence recovery after photobleaching. Glycerinated myofibrils were able to bind fluorescent myosin in a similar pattern in the presence or absence of MgATP, indicating that actin-myosin interactions had little effect on this process. Fluorescent heavy meromyosin did not incorporate into myofibrillar structures after injection. Light meromyosin, however, associated with A-bands as did whole myosin. These results suggest that microinjected myosin, even with its relatively low solubility under the cytoplasmic ionic condition, is capable of association with physiological structures in living muscle cells. Additionally, the light meromyosin portion of the molecule appears to be mainly responsible for the incorporation.

scholarly journals FILAMENT ULTRASTRUCTURE AND ORGANIZATION IN VERTEBRATE SMOOTH MUSCLE

1967 ◽  
Vol 35 (2) ◽  
pp. 303-321 ◽  
Author(s):  
Bernard J. Panner ◽  
Carl R. Honig
Keyword(s):  
Electron Microscopy ◽  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Actin Filaments ◽  
Heavy Meromyosin ◽  
Dense Bodies ◽  
Contraction Mechanism ◽  
Dark Staining ◽  
Technical Factors ◽  
Low Ionic Strength

Using a variety of preparative techniques for electron microscopy, we have obtained evidence for the disposition of actin and myosin in vertebrate smooth muscle. All longitudinal myofilaments seen in sections appear to be actin. Previous reports of two types of longitudinal filaments in sections are accounted for by technical factors, and by differentiated areas of opacity along individual filaments. Dense bodies with actin emerging from both ends have been identified in homogenates, and resemble Z discs from skeletal muscle (Huxley, 1963). In sections, short, dark-staining lateral filaments 15–25 A in diameter link adjacent actin filaments within dense bodies and in membrane dense pataches. They appear homologous with Z-disc filaments. Similar lateral filaments connect actin to plasma membrane. Dense bodies and dense patches, therefore, are attachment points and denote units analogous to sarcomeres. In glycerinated, methacrylate-embedded sections, lateral processes different in length and staining characteristics from lateral filaments in dense bodies exist at intervals along actin filaments. These processes are about 30 A wide and resemble heavy meromyosin from skeletal muscle. They also resemble heads of whole molecules of myosin in negatively stained material from gizzard homogenates. Intact single myosin molecules and dimers have been found, both free and attached to actin, even in media of very low ionic strength. Myosin can, therefore, exist in relatively disaggregated form. Models of the contraction mechanism of smooth muscle are proposed. The unique features are: (1) Myosin exists as small functional units. (2) Movement occurs by interdigitation and sliding of actin filaments.

Factors affecting movement of F-actin filaments propelled by skeletal muscle heavy meromyosin

1992 ◽  
Vol 262 (3) ◽  
pp. C714-C723 ◽  
Author(s):  
E. Homsher ◽  
F. Wang ◽  
J. R. Sellers
Keyword(s):  
Skeletal Muscle ◽  
Ionic Strength ◽  
Actin Filament ◽  
Molecular Motors ◽  
Actin Filaments ◽  
Heavy Meromyosin ◽  
Shortening Velocity ◽  
Weakly Bound ◽  
Factors Affecting ◽  
Cross Bridges

The measurement of fluorescent-labeled actin filament movement driven by mechanoenzymes (e.g., myosin) is an important methodology for the study of molecular motors. It is assumed that the filament velocity (Vf) is analogous to the unloaded shortening velocity (Vu) seen in muscle fibers. Methods are described to reproducibly quantitate the movement of these filaments and to select uniformly moving filaments and specify their Vf. Use of these techniques allowed comparison of Vf to literature values for Vu with regard to [ATP], [ADP], [Pi], pH, ionic strength (10-150 mM), and temperature (15-30 degrees C). Vf and Vu are quantitatively similar with respect to the effects of substrate and product concentrations and temperatures greater than 20 degrees C. However, Vf is more sensitive to decreases in pH and temperatures less than 20 degrees C than Vu. At ionic strengths of 50-150 mM, Vf and Vu exhibit similar ionic strength dependencies (decreasing with ionic strength). At ionic strengths less than 50 mM, Vf is markedly reduced. Results of experiments using adenosine 5'-O-(3-thiotriphosphate) suggest that increasing the number of weakly bound cross bridges does not seriously affect Vf. Thus, although Vf is a good analogue for Vu under certain conditions (elevated ionic strength and temperatures greater than 20 degrees C), under others it is not. The results of motility assays must be cautiously interpreted.

scholarly journals Movement generated by interactions between the dense material at the ends of microtubles and non-actin-containing microfilaments in Sticholonche zanclea.

1977 ◽  
Vol 72 (2) ◽  
pp. 314-338 ◽  
Author(s):  
J Cachon ◽  
M Cachon ◽  
L G Tilney ◽  
M S Tilney
Keyword(s):  
Skeletal Muscle ◽  
Cell Surface ◽  
Hip Joint ◽  
Small Diameter ◽  
Active Phase ◽  
Membrane System ◽  
Recovery Phase ◽  
Dense Material ◽  
Heavy Meromyosin ◽  
The Way

Axopods of the planktonic protozoan, Sticholonche, are used as oars to propel the organism through seawater. Within each axopod is an orgainzed array of microtubules which inserts into a dense material that assumes the form of the head of a hip joint. This material, in turn, articulates on the surface of the nucleus. Microfilaments, 20-30 A in diameter, connect the dense material associated with the microtubules to the surface of the nucleus, and they move the axopod by their contractions. The active phase of the movement may take as little as about 0.04 s and the recovery phase may take between 0.2 and 0.4 s. The microfilaments are not actin, as based on: (a) their small diameter, (b) the lack of decoration with heavy meromyosin, and (c) their ability to coil, spiral or fold during contraction. By the use of Thorotrast, we were able to demonstrate that the cell surface is deeply infolded, extending all the way to the hip joint. Here, there is a specialized membrane system that resembles the diad in skeletal muscle. From cytochemical tests and the use of ionophores and chelators, there is some evidence that the motile process may be controlled by calcium. This study demonstrates that, in at least one system, microtubules can be moves by contractile microfilaments attached to the dense material at there tips.

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