scholarly journals Post-Tetanic Calcium Transients In Adult Skeletal Muscle Fibers Are Frequency-Dependent And Fiber Type Specific

2009 ◽  
Vol 96 (3) ◽  
pp. 11a
Author(s):  
Mariana Casas ◽  
Reinaldo Figueroa ◽  
Isaac Garcia ◽  
Enrique Jaimovich
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Calcium Transients ◽  
Frequency Dependent ◽  
Adult Skeletal Muscle ◽  
Skeletal Muscle Fibers

scholarly journals Activity-dependent nuclear translocation and intranuclear distribution of NFATc in adult skeletal muscle fibers

2001 ◽  
Vol 155 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Yewei Liu ◽  
Zoltán Cseresnyés ◽  
William R. Randall ◽  
Martin F. Schneider
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Nuclear Translocation ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Adult Skeletal Muscle ◽  
Skeletal Muscle Fibers ◽  
Slow Twitch ◽  
Nuclear Foci ◽  
Fast Twitch

TTranscription factor nuclear factor of activated T cells NFATc (NFATc1, NFAT2) may contribute to slow-twitch skeletal muscle fiber type–specific gene expression. Green fluorescence protein (GFP) or FLAG fusion proteins of either wild-type or constitutively active mutant NFATc [NFATc(S→A)] were expressed in cultured adult mouse skeletal muscle fibers from flexor digitorum brevis (predominantly fast-twitch). Unstimulated fibers expressing NFATc(S→A) exhibited a distinct intranuclear pattern of NFATc foci. In unstimulated fibers expressing NFATc–GFP, fluorescence was localized at the sarcomeric z-lines and absent from nuclei. Electrical stimulation using activity patterns typical of slow-twitch muscle, either continuously at 10 Hz or in 5-s trains at 10 Hz every 50 s, caused cyclosporin A–sensitive appearance of fluorescent foci of NFATc–GFP in all nuclei. Fluorescence of nuclear foci increased during the first hour of stimulation and then remained constant during a second hour of stimulation. Kinase inhibitors and ionomycin caused appearance of nuclear foci of NFATc–GFP without electrical stimulation. Nuclear translocation of NFATc–GFP did not occur with either continuous 1 Hz stimulation or with the fast-twitch fiber activity pattern of 0.1-s trains at 50 Hz every 50 s. The stimulation pattern–dependent nuclear translocation of NFATc demonstrated here could thus contribute to fast-twitch to slow-twitch fiber type transformation.

scholarly journals Localization and Regulation of the N Terminal Splice Variant of PGC-1αin Adult Skeletal Muscle Fibers

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Tiansheng Shen ◽  
Yewei Liu ◽  
Martin F. Schneider
Keyword(s):  
Skeletal Muscle ◽  
Splice Variant ◽  
Nuclear Export ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Nuclear Accumulation ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Adult Skeletal Muscle ◽  
Skeletal Muscle Fibers

The transcriptional coactivator peroxisome proliferator-activated receptorγcoactivator 1α(PGC-1α) regulates expression of genes for metabolism and muscle fiber type. Recently, a novel splice variant of PGC-1α(NT-PGC-1α, amino acids 1–270) was cloned and found to be expressed in muscle. Here we use Flag-tagged NT-PGC-1αto examine the subcellular localization and regulation of NT-PGC-1αin skeletal muscle fibers. Flag-NT-PGC-1αis located predominantly in the myoplasm. Nuclear NT-PGC-1αcan be increased by activation of protein kinase A. Activation of p38 MAPK by muscle activity or of AMPK had no effect on the subcellular distribution of NT-PGC-1α. Inhibition of CRM1-mediated export only caused relatively slow nuclear accumulation of NT-PGC-1α, indicating that nuclear export of NT-PGC-1αmay be mediated by both CRM1-dependent and -independent pathways. Together these results suggest that the regulation of NT-PGC-1αin muscle fibers may be very different from that of the full-length PGC-1α, which is exclusively nuclear.

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

scholarly journals Phenotypic Modulation of Skeletal Muscle Fibers in LPIN1-Deficient Lipodystrophic (fld) Mice

2018 ◽  
Vol 56 (2) ◽  
pp. 322-331
Author(s):  
Rani S. Sellers ◽  
S. Radma Mahmood ◽  
Geoffrey S. Perumal ◽  
Frank P. Macaluso ◽  
Irwin J. Kurland
Keyword(s):  
Electron Microscopy ◽  
Skeletal Muscle ◽  
Fiber Type ◽  
Periodic Acid ◽  
Muscle Fibers ◽  
Myosin Atpase ◽  
Hybrid Fibers ◽  
Periodic Acid Schiff ◽  
Skeletal Muscle Fibers ◽  
Lipin 1

Lipin-1 ( Lpin1)–deficient lipodystrophic mice have scant and immature adipocytes and develop transient fatty liver early in life. Unlike normal mice, these mice cannot rely on stored triglycerides to generate adenosine triphosphate (ATP) from the β-oxidation of fatty acids during periods of fasting. To compensate, these mice store much higher amounts of glycogen in skeletal muscle and liver than wild-type mice in order to support energy needs during periods of fasting. Our studies demonstrated that there are phenotypic changes in skeletal muscle fibers that reflect an adaptation to this unique metabolic situation. The phenotype of skeletal muscle (soleus, gastrocnemius, plantaris, and extensor digitorum longus [EDL]) from Lpin1-/- was evaluated using various methods including immunohistochemistry for myosin heavy chains (Myh) 1, 2, 2a, 2b, and 2x; enzyme histochemistry for myosin ATPase, cytochrome-c oxidase (COX), and succinyl dehydrogenase (SDH); periodic acid–Schiff; and transmission electron microscopy. Fiber-type changes in the soleus muscle of Lpin1-/- mice were prominent and included decreased Myh1 expression with concomitant increases in Myh2 expression and myosin-ATPase activity; this change was associated with an increase in the presence of Myh1/2a or Myh1/2x hybrid fibers. Alterations in mitochondrial enzyme activity (COX and SDH) were apparent in the myofibers in the soleus, gastrocnemius, plantaris, and EDL muscles. Electron microscopy revealed increases in the subsarcolemmal mitochondrial mass in the muscles of Lpin1-/- mice. These data demonstrate that lipin-1 deficiency results in phenotypic fiber-specific modulation of skeletal muscle necessary for compensatory fuel utilization adaptations in lipodystrophy.

scholarly journals High-Fat Diet-Induced Insulin Resistance in Single Skeletal Muscle Fibers is Fiber Type Selective

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Mark W. Pataky ◽  
Haiyan Wang ◽  
Carmen S. Yu ◽  
Edward B. Arias ◽  
Robert J. Ploutz-Snyder ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
High Fat Diet ◽  
Fiber Type ◽  
Muscle Fibers ◽  
High Fat ◽  
Skeletal Muscle Fibers

scholarly journals Resveratrol regulates skeletal muscle fibers switching through the AdipoR1-AMPK-PGC-1α pathway

2019 ◽  
Vol 10 (6) ◽  
pp. 3334-3343 ◽  
Author(s):  
Qinyang Jiang ◽  
Xiaofang Cheng ◽  
Yueyue Cui ◽  
Qin Xia ◽  
Xueyu Yan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Underlying Mechanism ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Type ◽  
Skeletal Muscle Fibers

This study was conducted to investigate the effect and underlying mechanism of Resveratrol (RES) in regulating skeletal muscle fiber-type switching.

scholarly journals Arsenazo III and antipyrylazo III calcium transients in single skeletal muscle fibers.

1982 ◽  
Vol 79 (4) ◽  
pp. 679-707 ◽  
Author(s):  
P Palade ◽  
J Vergara
Keyword(s):  
Skeletal Muscle ◽  
Voltage Clamp ◽  
Spectral Characteristics ◽  
Muscle Fibers ◽  
Calcium Transients ◽  
Arsenazo Iii ◽  
Tension Development ◽  
Skeletal Muscle Fibers ◽  
Concentration Changes

The metallochrome calcium indicators arsenazo III and antipyrylazo III have been introduced individually into cut single frog skeletal muscle fibers from which calcium transients have been elicited either by action potential stimulation or by voltage-clamp pulses of up to 50 ms in duration. Calcium transients recorded with both dyes at selected wavelengths have similar characteristics when elicited by action potentials. Longer voltage-clamp pulse stimulation reveals differences in the late phases of the optical signals obtained with the two dyes. The effects of different tension blocking methods on Ca transients were compared experimentally. Internal application of EGTA at concentrations up to 3 mM was demonstrated to be efficient in blocking movement artifacts without affecting Ca transients. Higher EGTA concentrations affect the Ca signals' characteristics. Differential effects of internally applied EGTA on tension development as opposed to calcium transients suggest that diffusion with binding from Ca++ release sites to filament overlap sites may be significant. The spectral characteristics of the absorbance transients recorded with arsenazo III suggest that in situ recorded signals cannot be easily interpreted in terms of Ca concentration changes. A more exhaustic knowledge of the dye chemistry and/or in situ complications in the use of the dye will be necessary.

scholarly journals Activity- and Calcineurin-independent Nuclear Shuttling of NFATc1, but Not NFATc3, in Adult Skeletal Muscle Fibers

2006 ◽  
Vol 17 (4) ◽  
pp. 1570-1582 ◽  
Author(s):  
Tiansheng Shen ◽  
Yewei Liu ◽  
Zoltán Cseresnyés ◽  
Arie Hawkins ◽  
William R. Randall ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Nuclear Export ◽  
Muscle Fibers ◽  
Nuclear Accumulation ◽  
Leptomycin B ◽  
Adult Skeletal Muscle ◽  
Casein Kinase 1 ◽  
Nuclear Uptake ◽  
Skeletal Muscle Fibers

The transcription factor NFATc1 may be involved in slow skeletal muscle gene expression. NFATc1 translocates from cytoplasm to nuclei during slow fiber type electrical stimulation of skeletal muscle fibers because of activation of the Ca2+-dependent phosphatase calcineurin, resulting in nuclear factor of activated T-cells (NFAT) dephosphorylation and consequent exposure of its nuclear localization signal. Here, we find that unstimulated adult skeletal muscle fibers exhibit a previously unanticipated nucleocytoplasmic shuttling of NFATc1 without appreciable nuclear accumulation. In resting fibers, the nuclear export inhibitor leptomycin B caused nuclear accumulation of NFATc1 (but not of isoform NFATc3) and formation of NFATc1 intranuclear bodies independent of calcineurin. The rate of nuclear uptake of NFATc1 was 4.6 times lower in resting fibers exposed to leptomycin B than during electrical stimulation. Inhibitors of glycogen synthase kinase and protein kinase A or of casein kinase 1 slowed the decay of nuclear NFATc1 after electrical stimulation, but they did not cause NFATc1 nuclear uptake in unstimulated fibers. We propose that two nuclear translocation pathways, one pathway mediated by calcineurin activation and NFAT dephosphorylation and the other pathway independent of calcineurin and possibly independent of NFAT dephosphorylation, determine the distribution of NFATc1 between cytoplasm and nuclei in adult skeletal muscle.

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