scholarly journals A proposed role for non-junctional transverse tubules in skeletal muscle as flexible segments allowing expansion of the transverse network

2019 ◽  
Vol 29 (2) ◽  
Author(s):  
Manuela Lavorato ◽  
Ramesh Iyer ◽  
Clara Franzini-Armstrong
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Skeletal Muscles ◽  
Sarcomere Length ◽  
Muscle Fibers ◽  
Entire Length ◽  
Small Fish ◽  
Transverse Tubules ◽  
T Tubules

Using a variety of technical approaches, we have detected the presence of continuous triads that cover the entire length of T tubules in the main white body muscles of several small fish. This is in contrast to the discontinuous association of sarcoplasmic reticulum with T tubules in the red muscles from the same fish as well as in all other previously described muscles in a large variety of skeletal muscles. We suggest that continuous triads are permissible only in muscle fibers that are not normally subject to significant changes in sarcomere length during normal in vivo activity, as is the case for white muscles in the trunk of fish.

Chimeric calsequestrin and its targeting to the junctional sarcoplasmic reticulum of skeletal muscle

1997 ◽  
Vol 272 (5) ◽  
pp. C1420-C1428 ◽  
Author(s):  
A. Nori ◽  
K. A. Nadalini ◽  
A. Martini ◽  
R. Rizzuto ◽  
A. Villa ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Confocal Microscopy ◽  
Soleus Muscle ◽  
Hela Cells ◽  
Skeletal Muscles ◽  
Intracellular Localization ◽  
Primary Cultures ◽  
Muscle Fibers ◽  
Junctional Sarcoplasmic Reticulum

Calsequestrin (CS) is the junctional sarcoplasmic reticulum (jSR) Ca2+ binding protein responsible for intraluminal Ca2+ storage. The targeting mechanisms of CS to the jSR are yet to be unraveled. The nine-amino acid epitope of the influenza virus hemoagglutinin (referred to as HA1) was added at the COOH-terminal of CS by polymerase chain reaction cloning. The HA1-tagged CS cDNA was transiently transfected in either HeLa cells, myogenic cell lines, such as C2 and L8 cells, myoblasts of rat skeletal muscle primary cultures, or regenerating soleus muscle fibers of adult rats. The expression and intracellular localization of chimeric CS-HA1 were monitored by epifluorescence and confocal microscopy using either anti-CS antibodies or anti-HA1 antibodies. About 30% of transfected HeLa cells and 20-40% of myogenic cells expressed CS-HA1 into intracellular compartments, such as the perinuclear cisternae of endoplasmic reticulum (ER). Myoblasts of newborn rat skeletal muscles were first transfected and subsequently stimulated to differentiate into myotubes. CS-HA1 was detected in approximately 20% of transfected myotubes and did not affect CS distribution in myotubes. In the soleus muscle of adult rat, intramuscular injection of bupivacaine induced necrosis followed by regeneration. In vivo transfection of HA1-tagged CS cDNA in regenerating skeletal muscles determined expression in a few skeletal muscle fibers; CS-HA1 was localized only in jSR, as judged by confocal microscopy of longitudinal sections. The present results show that chimeric CS-HA1 is correctly sorted to ER/SR compartments and that the free COOH-terminal is not requested for sorting, retention, and segregation of CS to the SR.

scholarly journals JARINGAN OTOT RANGKA Sistem membran dan struktur halus unit kontraktil

2014 ◽  
Vol 6 (3) ◽  
Author(s):  
Sunny Wangko
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Connective Tissue ◽  
Muscle Tissue ◽  
Muscle Fibers ◽  
Membrane System ◽  
Transverse Tubules ◽  
Foot Structure ◽  
Cross Bridges ◽  
Main Components

Abstract: There are three main components of skeletal muscle: connective tissue, muscle tissue, and membrane system. The connective tissue protects the muscle fibers and separate them into fasicles. The skeletal muscle consists of paralel muscle fibers with their myofibrils which are composed by smaller contractile units, thick myofilaments and thin myofilaments. The membrane system consists of sarcolemma, transverse tubules (TT), foot structure, and sarcoplasmic reticulum (SR) with its cisternae. Depolarization of the sarcolemma spreads to TT, foot structure, and SR, resulting in the release of Ca2+ ions from SR. These ions trigger the formation of cross bridges to begin a contraction.Keywords: sarcolemma, T tubule, sarcoplasmic reticulum, thick myofilament, thin myofilamentAbstrak: Terdapat tiga komponen utama jaringan otot rangka, yaitu: jaringan ikat, jaringan otot seran lintang, dan sistem membran. Jaringan ikat berfungsi melindungi serat-serat otot dan memisahkannya atas berkas-berkas otot. Jaringan otot rangka tersusun atas serat-serat otot yang bherjalan sejajar dengan miofibrilnya yang terdiri atas unit kontraktil yang lebih kecil yaitu miofilamen tebal dan tipis. Sistem membran terdiri atas sarkolema dimana terjadinya depolarisasi yang paling awal dan dihantarkan ke dalam serat otot melalui tubulus T, struktur kaki pada daerah triad, dan sisterna terminalis yang selanjutnya memicu pelepasan ion Ca2+ dari retikulum sarkoplasma. Ion Ca2+ merupakan pemicu untuk pembentukan jembatan silang yang mengawali suatu kontraksi otot.Kata kunci: sarkolema, tubulus T, retikulum sarkoplasma, filamen tebal, filamen tipis

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.

Transport pathway, maturation, and targetting of the vesicular stomatitis virus glycoprotein in skeletal muscle fibers

1996 ◽  
Vol 109 (6) ◽  
pp. 1585-1596
Author(s):  
P. Rahkila ◽  
A. Alakangas ◽  
K. Vaananen ◽  
K. Metsikko
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Sarcoplasmic Reticulum ◽  
Vesicular Stomatitis Virus ◽  
Muscle Fibers ◽  
Viral Glycoprotein ◽  
Transverse Tubules ◽  
Skeletal Muscle Fibers ◽  
Vesicular Stomatitis ◽  
Terminal Cisternae

We have infected isolated skeletal muscle fibers with the vesicular stomatitis virus or the mutant tsO45, whose glycoprotein is blocked in the endoplasmic reticulum at 39 degrees C. Immunofluorescence analysis for the viral glycoprotein indicated that the fibers were infected over their entire length at a virus dose of 10(9)/ml. When we infected the myofibers with the tsO45 mutant at 39 degrees C, the viral glycoprotein appeared to be localised to the terminal cisternae of the sarcoplasmic reticulum. Upon shifting the cultures to the permissive temperature, 32 degrees C, in the presence of dinitrophenol, which blocks vesicular transport, the viral glycoprotein proceeded to completely fill the sarcoplasmic reticulum. Thus, both the endoplasmic reticulum located at the terminal cisternae of the sarcoplasmic reticulum, and the entire endoplasmic and sarcoplasmic reticulum appeared to be continuous. Shifting the culture temperature from 39 degrees C to 20 degrees C, resulted in prominent perinuclear staining throughout the fibers, accompanied by the appearance of distinct bright dots between the nuclei. Electron microscopic immunoperoxidase labeling indicated that these bright structures represented the Golgi apparatus. When either the tsO45-infected or wild-type virus-infected fibers were incubated at 32 degrees C, the viral glycoprotein showed a staining pattern that consisted of double rows of punctate fluorescence. Immunogold labeling showed that the viral glycoprotein was present in both the transverse tubules as well as the endoplasmic/sarcoplasmic reticulum endomembranes. In addition, extensive viral budding was observed in the transverse tubules. Metabolic labeling experiments revealed that only half of the glycoprotein was processed in the Golgi, and this processed form had become incorporated into the budding viral particles. Thus, the processed viral glycoprotein was targeted to the transverse tubules. The other half of the glycoprotein remained endoglycosidase H-sensitive, suggesting its retention in the endoplasmic/sarcoplasmic reticulum endomembranes.

The Collapse of the Sarcoplasmic Reticulum in Skeletal Muscle

1978 ◽  
Vol 33 (7-8) ◽  
pp. 561-573 ◽  
Author(s):  
Joachim R. Sommer ◽  
Nancy R. Wallace ◽  
Wilhelm Hasselbach
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Action Potential ◽  
Muscle Fibers ◽  
Membrane Capacitance ◽  
Frog Skeletal Muscle ◽  
Skeletal Muscle Fibers ◽  
Plausible Mechanism

Abstract When various cations, including Ca2+, are in the fixative, both sarcoplasmic reticulum (SR) of whole skeletal muscle and isolated SR vesicles collapse to form pentalaminate “compound membranes” that result from the apparent fusion of the lumenal lamellae of the membranous envelope of the SR. The process may be reversed by subsequently soaking the tissue in 1 ᴍ NaCl. An identical morphological phenomenon is observed in unfixed quickly frozen isolated frog skeletal muscle fibers, the cation in that case coming from endogenous sources. The hypothesis is advanced that the collapse is an in vivo process mediated by the sequestration of Ca2+ after contraction. The resulting obliteration of the SR lumen would have the effect of displacing the SR contents into the junctional SR, as well as electrically isolating the free SR from the junctional SR during relaxation. As a consequence, resistive coupling between the plasmalemma and the junctional SR becomes a plausible mechanism for the translation of the action potential into Ca2+ release, since the bulk of the SR membrane capacitance would now remain separated from the plasmalemma during relaxation.

scholarly journals Catalase in skeletal muscle fibers.

1979 ◽  
Vol 27 (4) ◽  
pp. 814-819 ◽  
Author(s):  
K N Christie ◽  
P J Stoward
Keyword(s):  
Skeletal Muscle ◽  
Hydrogen Peroxide ◽  
Sarcoplasmic Reticulum ◽  
Skeletal Muscles ◽  
Thin Filament ◽  
Muscle Fibers ◽  
Type I ◽  
Skeletal Muscle Fibers ◽  
Type I Fibers

Catalase has been localized immunocytochemically with anti-bovine catalase in long thin filament structures in aerobic type I fibers in the skeletal muscles of normal and genetically dystrophic hamsters. The filaments range in length from 1 to 60 micron, are orientated regularly along the long axis of the fibers, and also seem to surround and project from muscle nuclei. The enzyme thus appears to be more prominent in the sarcoplasmic reticulum than in peroxisomes, and in this situation is suitably placed for destroying toxic hydrogen peroxide which may be continously generated in aerobic fibers.

Coordinated development of myofibrils, sarcoplasmic reticulum and transverse tubules in normal and dysgenic mouse skeletal muscle, in vivo and in vitro

1992 ◽  
Vol 150 (2) ◽  
pp. 266-280 ◽  
Author(s):  
Bernhard E. Flucher ◽  
Johanna L. Phillips ◽  
Jeanne A. Powell ◽  
S.Brian Andrews ◽  
Mathew P. Daniels
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Coordinated Development ◽  
Transverse Tubules ◽  
Mouse Skeletal Muscle

Rapid and reciprocal regulation of tenascin-C and tenascin-Y expression by loading of skeletal muscle

2000 ◽  
Vol 113 (20) ◽  
pp. 3583-3591 ◽  
Author(s):  
M. Fluck ◽  
V. Tunc-Civelek ◽  
M. Chiquet
Keyword(s):  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Tensile Stress ◽  
Muscle Fibers ◽  
Myotendinous Junction ◽  
Left Wing ◽  
C Protein ◽  
Tenascin C ◽  
Mrna Induction

Tenascin-C and tenascin-Y are two structurally related extracellular matrix glycoproteins that in many tissues show a complementary expression pattern. Tenascin-C and the fibril-associated minor collagen XII are expressed in tissues bearing high tensile stress and are located in normal skeletal muscle, predominantly at the myotendinous junction that links muscle fibers to tendon. In contrast, tenascin-Y is strongly expressed in the endomysium surrounding single myofibers, and in the perimysial sheath around fiber bundles. We previously showed that tenascin-C and collagen XII expression in primary fibroblasts is regulated by changes in tensile stress. Here we have tested the hypothesis that the expression of tenascin-C, tenascin-Y and collagen XII in skeletal muscle connective tissue is differentially modulated by mechanical stress in vivo. Chicken anterior latissimus dorsi muscle (ALD) was mechanically stressed by applying a load to the left wing. Within 36 hours of loading, expression of tenascin-C protein was ectopically induced in the endomysium along the surface of single muscle fibers throughout the ALD, whereas tenascin-Y protein expression was barely affected. Expression of tenascin-C protein stayed elevated after 7 days of loading whereas tenascin-Y protein was reduced. Northern blot analysis revealed that tenascin-C mRNA was induced in ALD within 4 hours of loading while tenascin-Y mRNA was reduced within the same period. In situ hybridization indicated that tenascin-C mRNA induction after 4 hours of loading was uniform throughout the ALD muscle in endomysial fibroblasts. In contrast, the level of tenascin-Y mRNA expression in endomysium appeared reduced within 4 hours of loading. Tenascin-C mRNA and protein induction after 4–10 hours of loading did not correlate with signs of macrophage infiltration. Tenascin-C protein decreased again with removal of the load and nearly disappeared after 5 days. Furthermore, loading was also found to induce expression of collagen XII mRNA and protein, but to a markedly lower level, with slower kinetics and only partial reversibility. The results suggest that mechanical loading directly and reciprocally controls the expression of extracellular matrix proteins of the tenascin family in skeletal muscle.

scholarly journals Caveolin-3 Associates with Developing T-tubules during Muscle Differentiation

1997 ◽  
Vol 136 (1) ◽  
pp. 137-154 ◽  
Author(s):  
Robert G. Parton ◽  
Michael Way ◽  
Natasha Zorzi ◽  
Espen Stang
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Muscle Cells ◽  
Membrane System ◽  
C2c12 Cells ◽  
Double Labeling ◽  
Specific Antibodies ◽  
T Tubules ◽  
Α1 Subunit

Caveolae, flask-shaped invaginations of the plasma membrane, are particularly abundant in muscle cells. We have recently cloned a muscle-specific caveolin, termed caveolin-3, which is expressed in differentiated muscle cells. Specific antibodies to caveolin-3 were generated and used to characterize the distribution of caveolin-3 in adult and differentiating muscle. In fully differentiated skeletal muscle, caveolin-3 was shown to be associated exclusively with sarcolemmal caveolae. Localization of caveolin-3 during differentiation of primary cultured muscle cells and development of mouse skeletal muscle in vivo suggested that caveolin-3 is transiently associated with an internal membrane system. These elements were identified as developing transverse-(T)-tubules by double-labeling with antibodies to the α1 subunit of the dihydropyridine receptor in C2C12 cells. Ultrastructural analysis of the caveolin-3– labeled elements showed an association of caveolin-3 with elaborate networks of interconnected caveolae, which penetrated the depths of the muscle fibers. These elements, which formed regular reticular structures, were shown to be surface-connected by labeling with cholera toxin conjugates. The results suggest that caveolin-3 transiently associates with T-tubules during development and may be involved in the early development of the T-tubule system in muscle.

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