scholarly journals Presence of enolase in the M-band of skeletal muscle and possible indirect interaction with the cytosolic muscle isoform of creatine kinase

1999 ◽  
Vol 338 (1) ◽  
pp. 115-121 ◽  
Author(s):  
Georges FOUCAULT ◽  
Monique VACHER ◽  
Tatyana MERKULOVA ◽  
Angelica KELLER ◽  
Martine ARRIO-DUPONT
Keyword(s):  
Skeletal Muscle ◽  
Creatine Kinase ◽  
Energy Metabolism ◽  
Direct Interaction ◽  
Cross Linking ◽  
Muscle Fibres ◽  
Skinned Fibres ◽  
Two Dimensional Gel Electrophoresis ◽  
The Cross ◽  
Skeletal Muscle Fibres

Glycerol-skinned skeletal muscle fibres retain the defined sarcomeric structure of the myofibrils. We show here that a small fraction of two enzymes important for energy metabolism, the cytosolic muscle isoform of creatine kinase (EC 2.7.3.2), MM-creatine kinase (MM-CK), and enolase (EC 4.2.1.11), remains bound to skinned fibres. CK is slowly exchangeable, whereas enolase is firmly bound. Two-dimensional gel electrophoresis followed by Western blot analyses demonstrates that both α (ubiquitous) and β (muscle-specific) subunits of enolase are present in these preparations. Enolase and CK were co-localized at the M-band of the sarcomeres, as observed by indirect immunofluorescence and confocal microscopy. Cross-linking experiments were performed on skinned fibres with three bifunctional succinimidyl esters of different lengths and yielded a protein complex of 150 kDa that reacted with antibodies directed against either M-CK or β-enolase. The cross-linking efficiency was greatest for the longest reagent and zero for the shortest one. The length of the cross-linker giving a covalent complex between the two enzymes does not support the notion of a direct interaction between M-CK and enolase. This is the first demonstration of the presence of an enzyme of energy metabolism other than CK at the M-band of myofibres.

scholarly journals Ultrastructural remodelling of slow skeletal muscle fibres in creatine kinase deficient mice: a quantitative study

2016 ◽  
Vol 35 (04) ◽  
pp. 477-486 ◽  
Author(s):  
Marta Novotová ◽  
Bohumila Tarabová ◽  
Lucia Tylková ◽  
Renée Ventura-Clapier ◽  
Ivan Zahradník
Keyword(s):  
Skeletal Muscle ◽  
Creatine Kinase ◽  
Quantitative Study ◽  
Muscle Fibres ◽  
Slow Skeletal Muscle ◽  
Skeletal Muscle Fibres ◽  
Deficient Mice

scholarly journals BTP2 negatively regulates Orai1 and ryanodine receptor function in skeletal muscle

2020 ◽  
Author(s):  
Aldo Meizoso-Huesca ◽  
Bradley Launikonis
Keyword(s):  
Skeletal Muscle ◽  
Ryanodine Receptor ◽  
Muscle Fibres ◽  
Skinned Fibres ◽  
Ec Coupling ◽  
Hormetic Effect ◽  
Biphasic Effect ◽  
Dependent Inhibition ◽  
Skeletal Muscle Fibres ◽  
T System

Abstract Background. BTP2 is known to block Orai1, the Ca 2+ channel of store-operated Ca 2+ entry (SOCE) but no detailed analysis has been undertaken in skeletal muscle, where the drug has been used extensively to study SOCE. Methodology. We trapped a Ca 2+ sensitive dye in the tubular (t-) system of mechanically skinned fibres from rat to define the effect of BTP2 on SOCE in skeletal muscle fibres and used a cytoplasmic rhod-2 to track Ca 2+ release in the presence of BTP2. Results. In addition to blocking Orai1-dependent SOCE, we found a BTP2-dependent inhibition of Orai1 channel resting Ca 2+ conductance. Intriguingly, increasing concentrations of BTP2 displayed a hormetic effect on resting [Ca 2+ ] in the t-system ([Ca 2+ ] t-sys ), shifting from inducing an accumulation of Ca 2+ in the t-system presumably due to Orai1 channels blocking, to reducing the resting [Ca 2+ ] t-sys . This biphasic effect is not observed in presence of a ryanodine receptor (RyR) inhibitor, suggesting that above the hormetic zone, BTP2 impairs RyR function. Additionally, we found that BTP2 impairs the cytoplasmic Ca 2+ transients during repetitive excitation-contraction coupling (EC coupling) cycles independent of extracellular Ca 2+ entry. We determined that the release of Ca 2+ through the RyR was inhibited by BTP2, strongly suggesting that the RyR was the point of inhibition during the cycles of EC coupling. Conclusion. Our results show that both Ca 2+ channels, the Orai1 and RyR, are negatively regulated by BTP2, shedding new light on previous work that applied BTP2 to block SOCE in muscle.

scholarly journals BTP2 negatively regulates Orai1 and ryanodine receptor function in skeletal muscle

2020 ◽  
Author(s):  
Aldo Meizoso-Huesca ◽  
Bradley Launikonis
Keyword(s):  
Skeletal Muscle ◽  
Ryanodine Receptors ◽  
Muscle Fibres ◽  
Skinned Fibres ◽  
Ec Coupling ◽  
Hormetic Effect ◽  
Dependent Inhibition ◽  
Intact Muscle ◽  
Skeletal Muscle Fibres ◽  
T System

Abstract Background. BTP2 is known to block Orai1, the Ca2+ channel of store-operated Ca2+ entry (SOCE) but no detailed analysis has been undertaken in skeletal muscle, where the drug has been used extensively to study SOCE. Methodology. We trapped a Ca2+ sensitive dye in the tubular (t-) system of mechanically skinned fibres from rat to define the effect of BTP2 on SOCE in skeletal muscle fibres and used a cytoplasmic rhod-2 to track Ca2+ release in the presence of BTP2. Results. In addition to blocking Orai1-dependent SOCE, we found a BTP2-dependent inhibition of a resting Ca2+ conductance, likely to be through the Orai1 channel. Intriguingly, increasing concentrations of BTP2 displayed a hormetic effect on resting [Ca2+] in the t-system ([Ca2+]t−sys), shifting from inducing an accumulation of Ca2+ in the t-system presumably due to Orai1 channels blocking, to reducing the resting [Ca2+]t−sys. In absence of functional ryanodine receptors (RyRs), this biphasic effect was not observed, suggesting that above the hormetic zone, BTP2 impairs RyR function. Additionally, we found that BTP2 impairs the cytoplasmic Ca2+ transients during repetitive excitation-contraction coupling (EC coupling) cycles, independently of extracellular Ca2+ entry impairment. We determined that the release of Ca2+ through the RyR was inhibited by BTP2, strongly suggesting that the RyR was the point of inhibition during the cycles of EC coupling. Finally, we found that BTP2 inhibition of RyR-mediated Ca2+ release was independent of extracellular or intracellular application of the agent, indicating that BTP2 can impair RyR function in intact muscle. Conclusion. Our results show that both Ca2+ channels, the Orai1 and RyR, are negatively regulated by BTP2, shedding new light on previous work that applied BTP2 to block SOCE in muscle.

Interferon-gamma-like immunoreactivity and T-cell marker expression in rat skeletal muscle fibres

1989 ◽  
Vol 504 (2) ◽  
pp. 306-310 ◽  
Author(s):  
Inger Nennesmo ◽  
Tomas Olsson ◽  
Åke Ljungdahl ◽  
Krister Kristensson ◽  
Peter H. Van der Meide
Keyword(s):  
Skeletal Muscle ◽  
T Cell ◽  
Interferon Gamma ◽  
Muscle Fibres ◽  
Cell Marker ◽  
Rat Skeletal Muscle ◽  
Marker Expression ◽  
Skeletal Muscle Fibres
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