Myosin light chain phosphorylation in fast and slow skeletal muscles in situ

1984 ◽  
Vol 247 (5) ◽  
pp. C462-C471 ◽  
Author(s):  
R. L. Moore ◽  
J. T. Stull
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Skeletal Muscles ◽  
Myosin Light Chain ◽  
White Muscle ◽  
Slow Muscle ◽  
Phosphate Content ◽  
Slow Twitch ◽  
Fast Twitch

The physiological properties of contraction-induced phosphate incorporation into the phosphorylatable light chain (P-light chain) of myosin were examined in fast-twitch white, fast-twitch red, and slow-twitch skeletal muscles in situ. Neural stimulation of rat gastrocnemius muscles between 0.5 and 100 Hz produced an increase in the phosphate content of the P-light chain from the white portion of the muscle, and the rate of P-light chain phosphorylation was frequency dependent. The extent of phosphorylation of P-light chain from the fast-twitch red portion of the gastrocnemius muscle was less. In contrast to fast-twitch skeletal muscle, only high-frequency stimulation (30-100 Hz) produced a small increase in the phosphate content of P-light chain from the slow-twitch soleus muscle. Fast white muscle contained 2.2 and 3.5 times more myosin light chain kinase activity than did the fast red and slow muscle, respectively. The rate of P-light chain dephosphorylation was four times faster in slow muscle than in fast white muscle. Thus the greater extent of phosphorylation of P-light chain in fast-twitch white skeletal muscle fibers may be due in part to the presence of more kinase and less phosphatase activities. Isometric twitch tension potentiation was correlated to the extent of phosphorylation of P-light chain from fast white muscle. The physiological consequences of P-light chain phosphorylation are likely to be of greatest importance in fast-twitch white muscle.

Myosin light chain phosphorylation-dephosphorylation in mammalian skeletal muscle

1982 ◽  
Vol 242 (3) ◽  
pp. C234-C241 ◽  
Author(s):  
D. R. Manning ◽  
J. T. Stull
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Extensor Digitorum Longus ◽  
Myosin Light Chain ◽  
Extensor Digitorum Longus Muscle ◽  
Extensor Digitorum ◽  
Mammalian Skeletal Muscle ◽  
Phosphate Content ◽  
Longus Muscle ◽  
Fast Twitch

Phosphorylation of the myosin light chain 2 (LC2) subunit was examined in rat fast-twitch and slow-twitch skeletal muscles in response to repetitive stimulation at 23 and 35 degrees C and on incubation of fast-twitch skeletal muscle with isoproterenol. After a 1-s tetany at 35 degrees C, LC2 phosphate content in extensor digitorum longus muscle increased rapidly and transiently from 0.21 to 0.51 mol phosphate/mol LC2. This pattern of phosphorylation was similar to that observed at 23 degrees C. Increases in LC2 phosphate content were dependent on the frequency and duration of stimulation. In soleus muscle LC2 phosphate content was minimal following a 1-s tetany but increased markedly following more prolonged tetanies. On incubation of extensor digitorum longus muscle with isoproterenol (20 microM), LC2 phosphate content did not change, whereas phosphorylase a levels increased. A positive correlation existed between LC2 phosphate content and potentiation of peak twitch tension in both types of muscles, suggesting a physiological function for LC2 phosphorylation.

Molecular characterization of rat skeletal muscle myosin light chain kinase

1989 ◽  
Vol 256 (2) ◽  
pp. C399-C404 ◽  
Author(s):  
B. P. Herring ◽  
M. H. Nunnally ◽  
P. J. Gallagher ◽  
J. T. Stull
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Skeletal Muscles ◽  
Myosin Light Chain ◽  
Cardiac Tissue ◽  
Rat Skeletal Muscle ◽  
Skeletal Muscle Myosin ◽  
Slow Twitch ◽  
Muscle Myosin

A 1.85-kilobase (kb) cDNA has been isolated that encodes the catalytic and calmodulin binding domains of rat skeletal muscle myosin light chain kinase. The cDNA hybridized to a 3.3-kb RNA present in fast- and slow-twitch skeletal muscles. The reported enzymatic activity (3-fold greater in fast- than slow-twitch skeletal muscles) reflects the relative abundance of this RNA in the two types of skeletal muscle. No hybridization of the cDNA was detected to RNA isolated from smooth or nonmuscle tissues. The clone cross hybridized to a 2.2-kb RNA present in cardiac tissue. Ribonuclease protection analysis of skeletal and cardiac muscle RNA revealed major differences in the two hybridizing RNAs. Thus rat skeletal muscle contains a single myosin light chain kinase isoform, which is distinct from the cardiac, smooth, and nonmuscle forms.

Glutamine synthetase induction by glucocorticoids is preserved in skeletal muscle of aged rats

1996 ◽  
Vol 271 (6) ◽  
pp. E1061-E1066 ◽  
Author(s):  
D. Meynial-Denis ◽  
M. Mignon ◽  
A. Miri ◽  
J. Imbert ◽  
E. Aurousseau ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glutamine Synthetase ◽  
Skeletal Muscles ◽  
Female Rats ◽  
Mrna Levels ◽  
Aged Rats ◽  
Adult Rats ◽  
Adult Age ◽  
Slow Twitch ◽  
Fast Twitch

Glutamine synthetase (GS) is a glucocorticoid-inducible enzyme that has a key role for glutamine synthesis in muscle. We hypothesized that the glucocorticoid induction of GS could be altered in aged rats, because alterations in the responsiveness of some genes to glucocorticoids were reported in aging. We compared the glucocorticoid-induced GS in fast-twitch and slow-twitch skeletal muscles (tibialis anterior and soleus, respectively) and heart from adult (age 6-8 mo) and aged (age 22 mo) female rats. All animals received dexamethasone (Dex) in their drinking water (0.77 +/- 0.10 and 0.80 +/- 0.08 mg/day per adult and aged rat, respectively) for 5 days. Dex caused an increase in both GS activity and GS mRNA in fast-twitch and slow-twitch skeletal muscles from adult and aged rats. In contrast, Dex increased GS activity in heart of adult rats, without any concomitant change in GS mRNA levels. Furthermore, Dex did not affect GS activity in aged heart. Thus the responsiveness of GS to an excess of glucocorticoids is preserved in skeletal muscle but not in heart from aged animals.

scholarly journals Phosphorylation of the light-chain components of myosin from cardiac and red skeletal muscles

1975 ◽  
Vol 151 (1) ◽  
pp. 99-107 ◽  
Author(s):  
N Frearson ◽  
S V Perry
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Muscle ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Skeletal Muscles ◽  
Myosin Light Chain ◽  
Exchange Chromatography ◽  
Chain Fraction ◽  
Muscle Myosin ◽  
Modified Forms

1. The light-chain components of myosin from cardiac muscle (19000 and 27000 daltons) and of rabbit soleus and crureus muscles (19000, 27000 and 29000 daltons) were characterized. 2. The 19000-dalton components in carciac- and red-skeletal-muscle myosins were spontaneously modified to a component of slightly higher net negative charge. 3. The 19000-dalton component in cardiac and red skeletal muscles and their modified forms were phosphorylated by myosin light-chain kinase. 4. Evidence was obtained for the presence of myosin light-chain kinase in cardiac and red skeletal muscles. 5. Myosin light-chain kinase catalysed the phosphorylation of the whole light-chain fraction from white and red skeletal muscle at similar rates. The light-chain fraction of cardiac-muscle myosin was phosphorylated at a significantly lower rate. 6. The light-chain components of cardiac-muscle myosin and their phosphorylated froms were separated by ion-exchange chromatography and their amino acid compositions determined.

scholarly journals Myosin content of individual human muscle fibers isolated by laser capture microdissection

2016 ◽  
Vol 310 (5) ◽  
pp. C381-C389 ◽  
Author(s):  
Charles A. Stuart ◽  
William L. Stone ◽  
Mary E. A. Howell ◽  
Marianne F. Brannon ◽  
H. Kenton Hall ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Type I ◽  
Fiber Types ◽  
Myosin Heavy Chains ◽  
Heavy Chains ◽  
Slow Twitch ◽  
Type I Fibers ◽  
Fast Twitch ◽  
Laser Capture

Muscle fiber composition correlates with insulin resistance, and exercise training can increase slow-twitch (type I) fibers and, thereby, mitigate diabetes risk. Human skeletal muscle is made up of three distinct fiber types, but muscle contains many more isoforms of myosin heavy and light chains, which are coded by 15 and 11 different genes, respectively. Laser capture microdissection techniques allow assessment of mRNA and protein content in individual fibers. We found that specific human fiber types contain different mixtures of myosin heavy and light chains. Fast-twitch (type IIx) fibers consistently contained myosin heavy chains 1, 2, and 4 and myosin light chain 1. Type I fibers always contained myosin heavy chains 6 and 7 (MYH6 and MYH7) and myosin light chain 3 (MYL3), whereas MYH6, MYH7, and MYL3 were nearly absent from type IIx fibers. In contrast to cardiomyocytes, where MYH6 (also known as α-myosin heavy chain) is seen solely in fast-twitch cells, only slow-twitch fibers of skeletal muscle contained MYH6. Classical fast myosin heavy chains (MHC1, MHC2, and MHC4) were present in variable proportions in all fiber types, but significant MYH6 and MYH7 expression indicated slow-twitch phenotype, and the absence of these two isoforms determined a fast-twitch phenotype. The mixed myosin heavy and light chain content of type IIa fibers was consistent with its role as a transition between fast and slow phenotypes. These new observations suggest that the presence or absence of MYH6 and MYH7 proteins dictates the slow- or fast-twitch phenotype in skeletal muscle.

Phorbol esters affect skeletal muscle glucose transport in a fiber type-specific manner

2004 ◽  
Vol 287 (2) ◽  
pp. E305-E309 ◽  
Author(s):  
David C. Wright ◽  
Paige C. Geiger ◽  
Mark J. Rheinheimer ◽  
Dong Ho Han ◽  
John O. Holloszy
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Glucose Transport ◽  
Soleus Muscle ◽  
Insulin Signaling ◽  
Skeletal Muscles ◽  
Phorbol Esters ◽  
Serine Phosphorylation ◽  
Slow Twitch ◽  
Fast Twitch

Recent evidence has shown that activation of lipid-sensitive protein kinase C (PKC) isoforms leads to skeletal muscle insulin resistance. However, earlier studies demonstrated that phorbol esters increase glucose transport in skeletal muscle. The purpose of the present study was to try to resolve this discrepancy. Treatment with the phorbol ester 12-deoxyphorbol-13-phenylacetate 20-acetate (dPPA) led to an ∼3.5-fold increase in glucose transport in isolated fast-twitch epitrochlearis and flexor digitorum brevis muscles. Phorbol ester treatment was additive to a maximally effective concentration of insulin in fast-twitch skeletal muscles. Treatment with dPPA did not affect insulin signaling in the epitrochlearis. In contrast, phorbol esters had no effect on basal glucose transport and inhibited maximally insulin-stimulated glucose transport ∼50% in isolated slow-twitch soleus muscle. Furthermore, dPPA treatment inhibited the insulin-stimulated tyrosine phosphorylation of insulin receptor substrate (IRS)-1 and the threonine and serine phosphorylation of PKB by ∼50% in the soleus. dPPA treatment also caused serine phosphorylation of IRS-1 in the slow-twitch soleus muscle. In conclusion, our results show that phorbol esters stimulate glucose transport in fast-twitch skeletal muscles and inhibit insulin signaling in slow-twitch soleus muscle of rats. These findings suggest that mechanisms other than PKC activation mediate lipotoxicity-induced whole body insulin resistance.

scholarly journals Phosphorylation in vivo of the P light chain of myosin in rabbit fast and slow skeletal muscles

1984 ◽  
Vol 218 (3) ◽  
pp. 841-847 ◽  
Author(s):  
S A Westwood ◽  
O Hudlicka ◽  
S V Perry
Keyword(s):  
Light Chain ◽  
Skeletal Muscles ◽  
Time Course ◽  
Electrophoretic Mobilities ◽  
Slow Twitch Muscle ◽  
Post Tetanic Potentiation ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Frequency Of Stimulation

The P light chain of myosin is partially phosphorylated in resting slow and fast twitch skeletal muscles of the rabbit in vivo. The extent of P light-chain phosphorylation increases in both muscles on stimulation. Rabbit slow-twitch muscles contain two forms of the P light chain that migrate with the same electrophoretic mobilities as the two forms of P light chain in rabbit ventricular muscle. The rate of phosphorylation of the P light chain in slow-twitch muscle is slower than its rate of phosphorylation in fast-twitch muscles during tetanus. The rate of P light-chain dephosphorylation is slow after tetanic contraction of fast-twitch muscles in vivo. The time course of dephosphorylation does not correlate with the decline of post-tetanic potentiation of peak twitch tension in rabbit fast-twitch muscles. The frequency of stimulation is an important factor in determining the extent of P light-chain phosphorylation in fast- and slow-twitch muscles.

Effects of Exercise on Lactate Transport Into Mouse Skeletal Muscles

1994 ◽  
Vol 19 (3) ◽  
pp. 275-285 ◽  
Author(s):  
Arend Bonen ◽  
Karl J. A. McCullagh
Keyword(s):  
Skeletal Muscle ◽  
Key Words ◽  
Muscle Glycogen ◽  
Skeletal Muscles ◽  
Treadmill Exercise ◽  
Lactate Transport ◽  
Muscle Lactate ◽  
Slow Twitch ◽  
Fast Twitch

Skeletal muscle lactate transport was investigated in vitro in isolated fast-twitch (EDL) and slow-twitch soleus (Sol) skeletal muscles from control and exercised mice. Exercise (23 m/min, 8% grade) reduced muscle glycogen by 37% in EDL (p < 0.05) and by 35% in Sol muscles (p < 0.05). Lactate transport measurements (45 sec) were performed after 60 min of exercise in intact EDL and Sol muscles in vitro, at differing pH (6.5 and 7.4) and differing lactate concentrations (4 and 30 mM). Lactate transport was observed to be greater in Sol than in EDL (p < 0.05). In the exercised muscles there was a small but significant increase in lactate transport (p < 0.05). Lactate transport was greater when exogenous lactate concentrations were greater (p < 0.05) and more rapid at the lower pH (p < 0.05). These studies demonstrated that lactate transport was increased with exercise. Key words: soleus, EDL, treadmill exercise

Regulation of Cell Proliferation by Fast Myosin Light Chain 1 in Myoblasts Derived from Extraocular Muscle, Diaphragm and Gastrocnemius

2008 ◽  
Vol 233 (11) ◽  
pp. 1374-1384 ◽  
Author(s):  
Su-Zhen Zhang ◽  
Hui-Qi Xie ◽  
Yong Xu ◽  
Xiu-Qun Li ◽  
Ren-Qian Wei ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Skeletal Muscle ◽  
Cell Proliferation ◽  
Light Chain ◽  
Extraocular Muscle ◽  
Skeletal Muscles ◽  
Myosin Light Chain ◽  
S Phase ◽  
Two Dimensional Gel Electrophoresis ◽  
Tissue Samples

The extraocular muscle (EOM) suffers much less injury from Duchenne muscular dystrophy (DMD) than other skeletal muscles such as diaphragm and gastrocnemius. The present study was undertaken to test the hypothesis that differential expression of regulatory proteins between the EOM and other skeletal muscles is responsible for the observed difference in the sensitivity to DMD-associated damage. Protein expression in the tissue samples obtained from EOM, diaphragm or gastrocnemius of C57BL/6 mice was analyzed by two-dimensional gel electrophoresis and mass spectrometry. There were 35 proteins that were identified to be differentially expressed among different skeletal muscle tissues. Among the 35 proteins, a fast skeletal muscle isoform myosin light chain 1 (MLC1f) protein was further studied in relation to muscle cell proliferation. The EOM-derived myoblasts had much lower levels of MLC1f and higher rate of cell proliferation in contrast to the myoblasts derived from diaphragm or gastrocnemius, which displayed a higher expression of MLC1f along with a slow proliferation. Deletion of MLC1f using siRNA targeting MLC1f resulted in an increased rate of cell proliferation in the myoblasts. Cell cycle analysis revealed that MLC1f inhibited the transition of the cell cycle from the G1 to the S phase. Therefore, the present study demonstrates that MLC1f may negatively regulate proliferation of myoblasts through inhibition of the transition from the G1 to the S phase of the cell cycle. Low levels of MLC1f in myoblasts of EOM may ensure cell proliferation and enhance the repair process for EOM under the DMD disease condition, thus making EOM suffer less injury from DMD.

Temporal responses of oxidative vs. glycolytic skeletal muscles to K+ deprivation: Na+ pumps and cell cations

1999 ◽  
Vol 276 (6) ◽  
pp. C1411-C1419 ◽  
Author(s):  
Curtis B. Thompson ◽  
Cheolsoo Choi ◽  
Jang H. Youn ◽  
Alicia A. McDonough
Keyword(s):  
Skeletal Muscle ◽  
Posttranscriptional Regulation ◽  
Skeletal Muscles ◽  
Extracellular Fluid ◽  
Protein Levels ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Low K ◽  
Muscle Specificity ◽  
White Gastrocnemius

When K+ output exceeds input, skeletal muscle releases intracellular fluid K+ to buffer the fall in extracellular fluid (ECF) K+. To investigate the mechanisms and muscle specificity of the K+ shift, rats were fed K+-deficient chow for 2–10 days, and two muscles at phenotypic extremes were studied: slow-twitch oxidative soleus and fast-twitch glycolytic white gastrocnemius (WG). After 2 days of low-K+ chow, plasma K+ concentration ([K+]) fell from 4.6 to 3.7 mM, and Na+-K+-ATPase α2 (not α1) protein levels in both muscles, measured by immunoblotting, decreased 36%. Cell [K+] decreased from 116 to 106 mM in soleus and insignificantly in WG, indicating that α2 can decrease before cell [K+]. After 5 days, there were further decreases in α2 (70%) and β2 (22%) in WG, not in soleus, whereas cell [K+] decreased and cell [Na+] increased by 10 mM in both muscles. By 10 days, plasma [K+] fell to 2.9 mM, with further decreases in WG α2 (94%) and β2 (70%); cell [K+] fell 19 mM in soleus and 24 mM in WG compared with the control, and cell [Na+] increased 9 mM in soleus and 15 mM in WG; total homogenate Na+-K+-ATPase activity decreased 19% in WG and insignificantly in soleus. Levels of α2, β1, and β2 mRNA were unchanged over 10 days. The ratios of α2 to α1 protein levels in both control muscles were found to be nearly 1 by using the relative changes in α-isoforms vs. β1- (soleus) or β2-isoforms (WG). We conclude that the patterns of regulation of Na+ pump isoforms in oxidative and glycolytic muscles during K+ deprivation mediated by posttranscriptional regulation of α2β1 and α2β2 are distinct and that decreases in α2-isoform pools can occur early enough in both muscles to account for the shift of K+ to the ECF.

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