scholarly journals Calcium Ion in Skeletal Muscle: Its Crucial Role for Muscle Function, Plasticity, and Disease

2000 ◽  
Vol 80 (3) ◽  
pp. 1215-1265 ◽  
Author(s):  
Martin W. Berchtold ◽  
Heinrich Brinkmeier ◽  
Markus Müntener
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Binding Proteins ◽  
Muscle Fibers ◽  
Protein Isoforms ◽  
Muscle Performance ◽  
High Plasticity ◽  
Mammalian Skeletal Muscle ◽  
Variable Expression ◽  
Functional Features

Mammalian skeletal muscle shows an enormous variability in its functional features such as rate of force production, resistance to fatigue, and energy metabolism, with a wide spectrum from slow aerobic to fast anaerobic physiology. In addition, skeletal muscle exhibits high plasticity that is based on the potential of the muscle fibers to undergo changes of their cytoarchitecture and composition of specific muscle protein isoforms. Adaptive changes of the muscle fibers occur in response to a variety of stimuli such as, e.g., growth and differentition factors, hormones, nerve signals, or exercise. Additionally, the muscle fibers are arranged in compartments that often function as largely independent muscular subunits. All muscle fibers use Ca2+ as their main regulatory and signaling molecule. Therefore, contractile properties of muscle fibers are dependent on the variable expression of proteins involved in Ca2+ signaling and handling. Molecular diversity of the main proteins in the Ca2+ signaling apparatus (the calcium cycle) largely determines the contraction and relaxation properties of a muscle fiber. The Ca2+ signaling apparatus includes 1) the ryanodine receptor that is the sarcoplasmic reticulum Ca2+ release channel, 2) the troponin protein complex that mediates the Ca2+ effect to the myofibrillar structures leading to contraction, 3) the Ca2+pump responsible for Ca2+ reuptake into the sarcoplasmic reticulum, and 4) calsequestrin, the Ca2+storage protein in the sarcoplasmic reticulum. In addition, a multitude of Ca2+-binding proteins is present in muscle tissue including parvalbumin, calmodulin, S100 proteins, annexins, sorcin, myosin light chains, β-actinin, calcineurin, and calpain. These Ca2+-binding proteins may either exert an important role in Ca2+-triggered muscle contraction under certain conditions or modulate other muscle activities such as protein metabolism, differentiation, and growth. Recently, several Ca2+signaling and handling molecules have been shown to be altered in muscle diseases. Functional alterations of Ca2+ handling seem to be responsible for the pathophysiological conditions seen in dystrophinopathies, Brody's disease, and malignant hyperthermia. These also underline the importance of the affected molecules for correct muscle performance.

The Adaptive Potential of Skeletal Muscle Fibers

2002 ◽  
Vol 27 (4) ◽  
pp. 423-448 ◽  
Author(s):  
Dirk Pette
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Protein Isoforms ◽  
Mammalian Skeletal Muscle ◽  
Adaptive Potential ◽  
Hybrid Fibers ◽  
Neuromuscular Activity ◽  
Skeletal Muscle Fibers ◽  
Initial Location

Mammalian skeletal muscle fibers display a great adaptive potential. This potential results from the ability of muscle fibers to adjust their molecular, functional, and metabolic properties in response to altered functional demands, such as changes in neuromuscular activity or mechanical loading. Adaptive changes in the expression of myofibrillar and other protein isoforms result in fiber type transitions. These transitions occur in a sequential order and encompass a spectrum of pure and hybrid fibers. Depending on the quality, intensity, and duration of the alterations in functional demand, muscle fibers may undergo functional transitions in the direction of slow or fast, as well as metabolic transitions in the direction of aerobic-oxidative or glycotytic. The maximum range of possible transitions in either direction depends on the fiber phenotype and is determined by its initial location in the fiber spectrum. Key words: Ca-sequestering proteins, energy metabolism, fiber type transition, myofibrillar protein isofonns, myosin, neuromuscular activity

Effect of clenbuterol on sarcoplasmic reticulum function in single skinned mammalian skeletal muscle fibers

1998 ◽  
Vol 274 (6) ◽  
pp. C1718-C1726 ◽  
Author(s):  
Anthony J. Bakker ◽  
Stewart I. Head ◽  
Anthony C. Wareham ◽  
D. George Stephenson
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Rattus Norvegicus ◽  
Extensor Digitorum Longus ◽  
Muscle Fibers ◽  
Mammalian Skeletal Muscle ◽  
Direct Effects ◽  
Contraction Coupling ◽  
Slow Twitch

We examined the effect of the β2-agonist clenbuterol (50 μM) on depolarization-induced force responses and sarcoplasmic reticulum (SR) function in muscle fibers of the rat ( Rattus norvegicus; killed by halothane overdose) that had been mechanically skinned, rendering the β2-agonist pathway inoperable. Clenbuterol decreased the peak of depolarization-induced force responses in the extensor digitorum longus (EDL) and soleus fibers to 77.2 ± 9.0 and 55.6 ± 5.4%, respectively, of controls. The soleus fibers did not recover. Clenbuterol significantly and reversibly reduced SR Ca2+loading in EDL and soleus fibers to 81.5 ± 2.8 and 78.7 ± 4.0%, respectively, of controls. Clenbuterol also produced an ∼25% increase in passive leak of Ca2+ from the SR of the EDL and soleus fibers. These results indicate that clenbuterol has direct effects on fast- and slow-twitch skeletal muscle, in the absence of the β2-agonist pathway. The increased Ca2+ leak in the triad region may lead to excitation-contraction coupling damage in the soleus fibers and could also contribute to the anabolic effect of clenbuterol in vivo.

scholarly journals Comparison of the effects of inorganic phosphate on caffeine-induced Ca2+ release in fast- and slow-twitch mammalian skeletal muscle

2008 ◽  
Vol 294 (1) ◽  
pp. C97-C105 ◽  
Author(s):  
Giuseppe S. Posterino ◽  
Stacey L. Dunn
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Inorganic Phosphate ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Creatine Phosphate ◽  
Mammalian Skeletal Muscle ◽  
Time Integral ◽  
Slow Twitch ◽  
Fast Twitch

We compared the effects of 50 mM Pi on caffeine-induced Ca2+ release in mechanically skinned fast-twitch (FT) and slow-twitch (ST) skeletal muscle fibers of the rat. The time integral (area) of the caffeine response was reduced by ∼57% (FT) and ∼27% (ST) after 30 s of exposure to 50 mM Pi in either the presence or absence of creatine phosphate (to buffer ADP). Differences in the sarcoplasmic reticulum (SR) Ca2+ content between FT and ST fibers [∼40% vs. 100% SR Ca2+ content (pCa 6.7), respectively] did not contribute to the different effects of Pi observed; underloading the SR of ST fibers so that the SR Ca2+ content approximated that of FT fibers resulted in an even smaller (∼21%), but not significant, reduction in caffeine-induced Ca2+ release by Pi. These observed differences between FT and ST fibers could arise from fiber-type differences in the ability of the SR to accumulate Ca2+-Pi precipitate. To test this, fibers were Ca2+ loaded in the presence of 50 mM Pi. In FT fibers, the maximum SR Ca2+ content (pCa 6.7) was subsequently increased by up to 13 times of that achieved when loading for 2 min in the absence of Pi. In ST fibers, the SR Ca2+ content was only doubled. These data show that Ca2+ release in ST fibers was less affected by Pi than FT fibers, and this may be due to a reduced capacity of ST SR to accumulate Ca2+-Pi precipitate. This may account, in part, for the fatigue-resistant nature of ST fibers.

Disruption of the sarcolemma of mammalian skeletal muscle fibers by homogenization

1975 ◽  
Vol 39 (6) ◽  
pp. 1052-1055 ◽  
Author(s):  
W. G. Kerrick ◽  
B. Krasner
Keyword(s):  
Skeletal Muscle ◽  
Steady State ◽  
Sarcoplasmic Reticulum ◽  
Muscle Fibers ◽  
Mammalian Skeletal Muscle ◽  
Large Molecules ◽  
Single Fibers ◽  
Chemical Stimuli ◽  
Tension Transducer ◽  
Traditional Manner

A new method has been developed for mechanically disrupting the sarcolemma of mammalian sketletal muscle fibers (sarcolemma nonfunctional). Single fibers were produced from small pieces of the soleus muscle of the rabbit by gentle homogenization in a relaxing solution in a tissue homogenizer. These fibers were found to be longitudinally intact, with a sarcomere spacing of approximately 2.1 mum, permeable to large molecules of 10,000 MW, sensitive to the chemical stimuli that cause Ca2+ to be released from the sarcoplasmic reticulum, and responsive to Ca2+ in the same manner as frog fibers skinned in the traditional manner. The single fibers were mounted in a tension transducer and steady-state tensions were recorded in test solutions of different Ca2+ concentrations. The data did not differ statistically from data similarly obtained in identically prepared fibers that, in addition, we had longitudinally split in half to ensure disruption of the sarcolemmal barrier to the diffusion of ions.

scholarly journals Interdomain Interactions within Ryanodine Receptors Regulate Ca2+ Spark Frequency in Skeletal Muscle

2001 ◽  
Vol 119 (1) ◽  
pp. 15-32 ◽  
Author(s):  
Alexander Shtifman ◽  
Christopher W. Ward ◽  
Takeshi Yamamoto ◽  
Jianli Wang ◽  
Beth Olbinski ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Lipid Bilayers ◽  
Laser Scanning ◽  
Muscle Fibers ◽  
Mammalian Skeletal Muscle ◽  
Open Probability ◽  
Release Channel ◽  
Pronounced Increase ◽  
Open Time ◽  
Interdomain Interactions

DP4 is a 36-residue synthetic peptide that corresponds to the Leu2442-Pro2477 region of RyR1 that contains the reported malignant hyperthermia (MH) mutation site. It has been proposed that DP4 disrupts the normal interdomain interactions that stabilize the closed state of the Ca2+ release channel (Yamamoto, T., R. El-Hayek, and N. Ikemoto. 2000. J. Biol. Chem. 275:11618–11625). We have investigated the effects of DP4 on local SR Ca2+ release events (Ca2+ sparks) in saponin-permeabilized frog skeletal muscle fibers using laser scanning confocal microscopy (line-scan mode, 2 ms/line), as well as the effects of DP4 on frog SR vesicles and frog single RyR Ca2+ release channels reconstituted in planar lipid bilayers. DP4 caused a significant increase in Ca2+ spark frequency in muscle fibers. However, the mean values of the amplitude, rise time, spatial half width, and temporal half duration of the Ca2+ sparks, as well as the distribution of these parameters, remained essentially unchanged in the presence of DP4. Thus, DP4 increased the opening rate, but not the open time of the RyR Ca2+ release channel(s) generating the sparks. DP4 also increased [3H]ryanodine binding to SR vesicles isolated from frog and mammalian skeletal muscle, and increased the open probability of frog RyR Ca2+ release channels reconstituted in bilayers, without changing the amplitude of the current through those channels. However, unlike in Ca2+ spark experiments, DP4 produced a pronounced increase in the open time of channels in bilayers. The same peptide with an Arg17 to Cys17 replacement (DP4mut), which corresponds to the Arg2458-to-Cys2458 mutation in MH, did not produce a significant effect on RyR activation in muscle fibers, bilayers, or SR vesicles. Mg2+ dependence experiments conducted with permeabilized muscle fibers indicate that DP4 preferentially binds to partially Mg2+-free RyR(s), thus promoting channel opening and production of Ca2+ sparks.

scholarly journals Altering Skeletal Muscle EC Coupling by Ablating the Sarcoplasmic Reticulum Protein JP45 Affects Both Metabolism and Muscle Performance in Old Mice

2010 ◽  
Vol 98 (3) ◽  
pp. 547a
Author(s):  
Osvaldo Delbono ◽  
Zhong-Min Wang ◽  
Jackson Taylor ◽  
Maria Laura Messi ◽  
Susan Treves ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Muscle Performance ◽  
Ec Coupling ◽  
Old Mice

Mammalian skeletal muscle C-protein: purification from bovine muscle, binding to titin and the characterization of a full-length human cDNA

1992 ◽  
Vol 102 (4) ◽  
pp. 769-778
Author(s):  
D.O. Furst ◽  
U. Vinkemeier ◽  
K. Weber
Keyword(s):  
Skeletal Muscle ◽  
Protein Sequencing ◽  
Protein Isoforms ◽  
Fast Method ◽  
Mammalian Skeletal Muscle ◽  
Terminal Sequence ◽  
C Protein ◽  
Human Sequence ◽  
Associated Proteins ◽  
Bovine Skeletal Muscle

We report a fast method for the isolation of homogeneous C-protein from bovine skeletal muscle. In electron micrographs C-protein appears as short rods with a relatively uniform length of about 50 nm. Protein sequencing shows a single N-terminal sequence. Radio-labelled C-protein strongly decorates titin II and myosin rods but not myosin heads. Binding to titin II is retained in preparations lacking titin-associated proteins. Antibodies to bovine C-protein were used to screen a lambda gt11 cDNA library constructed from fetal human skeletal muscle. Clone HC38 is 3833 bp long and encodes a protein of 1138 amino acid residues. The start of the predicted sequence fits the N-terminal sequence of the bovine protein. All partial sequences obtained from the bovine protein (348 residues) and the sequence deduced from a partial chicken cDNA (Einheber and Fischman, 1990) can be aligned along the human sequence. The sequences of human and chicken C-proteins share 50% identity and 70% similarity. Along the repeat patterns of the human protein the fibronectin (Fn)-like domains are better conserved than the immunoglobulin (Ig)-like domains. Regions of strong divergence between chicken fast C-protein and human slow C-protein may represent differences in C-protein isoforms.

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