The Structural Basis of Contraction and Regulation in Skeletal Muscle

1976 ◽  
pp. 9-25 ◽  
Author(s):  
H. E. Huxley
Keyword(s):  
Skeletal Muscle ◽  
Structural Basis

Structural Basis of Tirasemtiv Activation of Fast Skeletal Muscle

2021 ◽  
Vol 64 (6) ◽  
pp. 3026-3034
Author(s):  
Monica X. Li ◽  
Pascal Mercier ◽  
James J. Hartman ◽  
Brian D. Sykes
Keyword(s):  
Skeletal Muscle ◽  
Structural Basis ◽  
Fast Skeletal Muscle

Structural Basis of Differences in Isoform-Specific Gating and Lidocaine Block between Cardiac and Skeletal Muscle Sodium Channels

2002 ◽  
Vol 61 (1) ◽  
pp. 136-141 ◽  
Author(s):  
Ronald A. Li ◽  
Irene L. Ennis ◽  
Gordon F. Tomaselli ◽  
Eduardo Marbán
Keyword(s):  
Skeletal Muscle ◽  
Sodium Channels ◽  
Structural Basis

scholarly journals The structural basis for intermitochondrial communications is fundamentally different in cardiac and skeletal muscle

2020 ◽  
Vol 105 (4) ◽  
pp. 606-612
Author(s):  
Manuela Lavorato ◽  
Federico Formenti ◽  
Clara Franzini-Armstrong
Keyword(s):  
Skeletal Muscle ◽  
Structural Basis

scholarly journals Sarcoplasmic reticulum–mitochondrial through-space coupling in skeletal muscleThis paper is one of a selection of papers published in this Special Issue, entitled 14th International Biochemistry of Exercise Conference – Muscles as Molecular and Metabolic Machines, and has undergone the Journal’s usual peer review process.

2009 ◽  
Vol 34 (3) ◽  
pp. 389-395 ◽  
Author(s):  
Robert T. Dirksen
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Release ◽  
Atp Hydrolysis ◽  
Peer Review Process ◽  
Muscle Relaxation ◽  
Structural Basis ◽  
Atp Production ◽  
Atp Generation ◽  
Selection Of

The skeletal muscle contractile machine is fueled by both calcium and ATP. Calcium ions activate the contractile machinery by binding to troponin C and relieving troponin-tropomyosin inhibition of actinomyosin interaction. ATP binding to myosin during the contractile cycle results in myosin detachment from actin, and energy liberated from subsequent ATP hydrolysis is then used to drive the next contractile cycle. ATP is also used to lower myoplasmic calcium levels during muscle relaxation. Thus, muscle contractility is intimately linked to the proper control of sarcomeric Ca2+ delivery and (or) removal and ATP generation and (or) utilization. In skeletal muscle, the sarcoplasmic reticulum (SR) is the primary regulator of calcium storage, release, and reuptake, while glycolysis and the mitochondria are responsible for cellular ATP production. However, the SR and mitochondrial function in muscle are not independent, as calcium uptake into the mitochondria increases ATP production by stimulating oxidative phosphorylation and mitochondrial ATP production, and production and (or) detoxification of reactive oxygen and nitrogen species (ROS/RNS), in turn, modulates SR calcium release and reuptake. Close spatial Ca2+/ATP/ROS/RNS communication between the SR and mitochondria is facilitated by the structural attachment of mitochondria to the calcium release unit (CRU) by 10 nm of electron-dense tethers. The resultant anchoring of mitochondria to the CRU provides a structural basis for maintaining bidirectional SR–mitochondrial through-space communication during vigorous contraction. This review will consider the degree to which this structural link enables privileged or microdomain communication between the SR and mitochondria in skeletal muscle.

scholarly journals Dependence of thick filament structure in relaxed mammalian skeletal muscle on temperature and interfilament spacing

2021 ◽  
Vol 153 (3) ◽  
Author(s):  
Marco Caremani ◽  
Luca Fusi ◽  
Marco Linari ◽  
Massimo Reconditi ◽  
Gabriella Piazzesi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Thick Filament ◽  
Structural Basis ◽  
Mammalian Skeletal Muscle ◽  
X Ray ◽  
Physiological Temperature ◽  
Thick Filaments ◽  
Filament Structure ◽  
Intact Muscle ◽  
Resting Muscle

Contraction of skeletal muscle is regulated by structural changes in both actin-containing thin filaments and myosin-containing thick filaments, but myosin-based regulation is unlikely to be preserved after thick filament isolation, and its structural basis remains poorly characterized. Here, we describe the periodic features of the thick filament structure in situ by high-resolution small-angle x-ray diffraction and interference. We used both relaxed demembranated fibers and resting intact muscle preparations to assess whether thick filament regulation is preserved in demembranated fibers, which have been widely used for previous studies. We show that the thick filaments in both preparations exhibit two closely spaced axial periodicities, 43.1 nm and 45.5 nm, at near-physiological temperature. The shorter periodicity matches that of the myosin helix, and x-ray interference between the two arrays of myosin in the bipolar filament shows that all zones of the filament follow this periodicity. The 45.5-nm repeat has no helical component and originates from myosin layers closer to the filament midpoint associated with the titin super-repeat in that region. Cooling relaxed or resting muscle, which partially mimics the effects of calcium activation on thick filament structure, disrupts the helical order of the myosin motors, and they move out from the filament backbone. Compression of the filament lattice of demembranated fibers by 5% Dextran, which restores interfilament spacing to that in intact muscle, stabilizes the higher-temperature structure. The axial periodicity of the filament backbone increases on cooling, but in lattice-compressed fibers the periodicity of the myosin heads does not follow the extension of the backbone. Thick filament structure in lattice-compressed demembranated fibers at near-physiological temperature is similar to that in intact resting muscle, suggesting that the native structure of the thick filament is largely preserved after demembranation in these conditions, although not in the conditions used for most previous studies with this preparation.

scholarly journals Nucleus-specific translation and assembly of acetylcholinesterase in multinucleated muscle cells.

1990 ◽  
Vol 110 (3) ◽  
pp. 715-719 ◽  
Author(s):  
R L Rotundo
Keyword(s):  
Skeletal Muscle ◽  
Cell Surface ◽  
Neuromuscular Junctions ◽  
Muscle Fibers ◽  
Structural Basis ◽  
Multinucleated Cells ◽  
Skeletal Muscle Fibers ◽  
Nuclear Domains ◽  
Nerve Muscle ◽  
Polypeptide Chains

Multinucleated skeletal muscle fibers synthesize cell surface and secreted oligomeric forms of acetylcholinesterase (AChE) that accumulate at specialized locations on the cell surface, such as sites of nerve-muscle contact. Using allelic variants of the AChE polypeptide chains as genetic markers, we show that nuclei homozygous for either the alpha or beta alleles residing in chimeric myotubes preferentially translate their AChE mRNAs on their respective ERs. These results indicate that the events of transcription, translation, and assembly of this membrane protein are compartmentalized into nuclear domains in multinucleated cells, and provide the structural basis for the possible localized expression and regulation of synaptic components at the neuromuscular junctions of vertebrate skeletal muscle fibers.

scholarly journals X-ray diffraction analysis of the effects of myosin regulatory light chain phosphorylation and butanedione monoxime on skinned skeletal muscle fibers

2016 ◽  
Vol 310 (8) ◽  
pp. C692-C700 ◽  
Author(s):  
Maki Yamaguchi ◽  
Masako Kimura ◽  
Zhao-bo Li ◽  
Tetsuo Ohno ◽  
Shigeru Takemori ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Muscle Fibers ◽  
Structural Basis ◽  
Myosin Regulatory Light Chain ◽  
X Ray Diffraction ◽  
Phosphate Release ◽  
X Ray ◽  
Thick Filaments ◽  
Butanedione Monoxime

The phosphorylation of the myosin regulatory light chain (RLC) is an important modulator of skeletal muscle performance and plays a key role in posttetanic potentiation and staircase potentiation of twitch contractions. The structural basis for these phenomena within the filament lattice has not been thoroughly investigated. Using a synchrotron radiation source at SPring8, we obtained X-ray diffraction patterns from skinned rabbit psoas muscle fibers before and after phosphorylation of myosin RLC in the presence of myosin light chain kinase, calmodulin, and calcium at a concentration below the threshold for tension development ([Ca2+] = 10−6.8 M). After phosphorylation, the first myosin layer line slightly decreased in intensity at ∼0.05 nm−1 along the equatorial axis, indicating a partial loss of the helical order of myosin heads along the thick filament. Concomitantly, the (1,1/1,0) intensity ratio of the equatorial reflections increased. These results provide a firm structural basis for the hypothesis that phosphorylation of myosin RLC caused the myosin heads to move away from the thick filaments towards the thin filaments, thereby enhancing the probability of interaction with actin. In contrast, 2,3-butanedione monoxime (BDM), known to inhibit contraction by impeding phosphate release from myosin, had exactly the opposite effects on meridional and equatorial reflections to those of phosphorylation. We hypothesize that these antagonistic effects are due to the acceleration of phosphate release from myosin by phosphorylation and its inhibition by BDM, the consequent shifts in crossbridge equilibria leading to opposite changes in abundance of the myosin-ADP-inorganic phosphate complex state associated with helical order of thick filaments.

scholarly journals The structural basis of the increase in isometric force production with temperature in frog skeletal muscle

2005 ◽  
Vol 567 (2) ◽  
pp. 459-469 ◽  
Author(s):  
M. Linari ◽  
E. Brunello ◽  
M. Reconditi ◽  
Y.-B. Sun ◽  
P. Panine ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Isometric Force ◽  
Force Production ◽  
Structural Basis ◽  
Frog Skeletal Muscle ◽  
Isometric Force Production
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