scholarly journals Progressive myopathy and defects in the maintenance of myotendinous junctions in mice that lack talin 1 in skeletal muscle

Development ◽  
2008 ◽  
Vol 135 (11) ◽  
pp. 2043-2053 ◽  
Author(s):  
F. J. Conti ◽  
A. Felder ◽  
S. Monkley ◽  
M. Schwander ◽  
M. R. Wood ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Myotendinous Junctions

scholarly journals Integrin-linked kinase stabilizes myotendinous junctions and protects muscle from stress-induced damage

2008 ◽  
Vol 180 (5) ◽  
pp. 1037-1049 ◽  
Author(s):  
Hao-Ven Wang ◽  
Ling-Wei Chang ◽  
Klara Brixius ◽  
Sara A. Wickström ◽  
Eloi Montanez ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Basement Membranes ◽  
Skeletal Muscle Regeneration ◽  
Integrin Subunit ◽  
Β1 Integrin ◽  
Progressive Muscular Dystrophy ◽  
Akt Activation ◽  
Impaired Insulin ◽  
Integrin Linked Kinase ◽  
Myotendinous Junctions

Skeletal muscle expresses high levels of integrin-linked kinase (ILK), predominantly at myotendinous junctions (MTJs) and costameres. ILK binds the cytoplasmic domain of β1 integrin and mediates phosphorylation of protein kinase B (PKB)/Akt, which in turn plays a central role during skeletal muscle regeneration. We show that mice with a skeletal muscle–restricted deletion of ILK develop a mild progressive muscular dystrophy mainly restricted to the MTJs with detachment of basement membranes and accumulation of extracellular matrix. Endurance exercise training enhances the defects at MTJs, leads to disturbed subsarcolemmal myofiber architecture, and abrogates phosphorylation of Ser473 as well as phosphorylation of Thr308 of PKB/Akt. The reduction in PKB/Akt activation is accompanied by an impaired insulin-like growth factor 1 receptor (IGF-1R) activation. Coimmunoprecipitation experiments reveal that the β1 integrin subunit is associated with the IGF-1R in muscle cells. Our data identify the β1 integrin–ILK complex as an important component of IGF-1R/insulin receptor substrate signaling to PKB/Akt during mechanical stress in skeletal muscle.

scholarly journals Talin at myotendinous junctions.

1986 ◽  
Vol 103 (4) ◽  
pp. 1465-1472 ◽  
Author(s):  
J G Tidball ◽  
T O'Halloran ◽  
K Burridge
Keyword(s):  
Skeletal Muscle ◽  
Actin Filaments ◽  
Skeletal Muscles ◽  
Immunofluorescence Microscopy ◽  
Protein Separations ◽  
Force Transmission ◽  
Electron Microscopic ◽  
Focal Contacts ◽  
Myotendinous Junctions

Junctions formed by skeletal muscles where they adhere to tendons, called myotendinous junctions, are sites of tight adhesion and where forces generated by the cell are placed on the substratum. In this regard, myotendinous junctions and focal contacts of fibroblasts in vitro are analogues. Talin is a protein located at focal contacts that may be involved in force transmission from actin filaments to the plasma membrane. This study investigates whether talin is also found at myotendinous junctions. Protein separations on SDS polyacrylamide gels and immunolabeling procedures show that talin is present in skeletal muscle. Immunofluorescence microscopy using anti-talin indicates that talin is found concentrated at myotendinous junctions and in lesser amounts in periodic bands over nonjunctional regions. Electron microscopic immunolabeling shows talin is a component of the digitlike processes of muscle cells that extend into tendons at myotendinous junctions. These findings indicate that there may be similarities in the molecular composition of focal contacts and myotendinous junctions in addition to functional analogies.

scholarly journals Expression and localization of the phosphoglucomutase-related cytoskeletal protein, aciculin, in skeletal muscle

1994 ◽  
Vol 107 (7) ◽  
pp. 1993-2003 ◽  
Author(s):  
A.M. Belkin ◽  
K. Burridge
Keyword(s):  
Skeletal Muscle ◽  
Cell Fusion ◽  
Muscle Tissue ◽  
Neuromuscular Junctions ◽  
Thigh Muscle ◽  
C2c12 Myotubes ◽  
Cytoskeletal Protein ◽  
Adult Skeletal Muscle ◽  
Cell Matrix ◽  
Myotendinous Junctions

Recently, a 60/63 kDa cytoskeletal protein, highly homologous to the glycolytic enzyme phosphoglucomutase (PGM 1), was isolated from smooth muscle tissue and shown to localize in various adherens-type junctions of muscle and some nonmuscle cells. Since this protein, tentatively named ‘aciculin’, was enriched in muscle tissues and cells, we have attempted to study its expression and localization during myodifferentiation. C2C12 mouse myoblasts did not express any aciculin before cell fusion in culture. Immediately after cell fusion aciculin became detectable and its content continued to rise during myotube maturation. In early myotubes aciculin appeared first at cell tips and was predominantly localized to focal adhesions of immature myotubes. As myotubes matured in culture, aciculin became associated with growing myofibrils, and finally was found redistributed in striations, corresponding to sarcomere Z-discs. Immunoblotting showed that aciculin content in chicken breast skeletal muscle remained very low until day 11 of embryogenesis, but significantly increased in late prenatal and early postnatal development. By immunofluorescence, aciculin was not revealed in thigh skeletal muscle of day 11 chicken embryos, but was prominently localized at myotendinous junctions in thigh muscle of day 16 embryos. Myotendinous junctions appeared to be major sites of aciculin accumulation in developing and mature skeletal muscle fibers in vivo, suggesting some role for this protein in thin filament-membrane interactions and, potentially, in force transmission at these cell-matrix contacts. In adult skeletal muscle faint aciculin staining appeared at the sarcolemma and as striations in register with Z-discs. Since the protein was not identified in glycerinated myofibrils but was localized to striations in C2C12 myotubes and within the limited areas on skeletal muscle tissue sections, we conclude that aciculin is a component of skeletal muscle costameres. In cultured C2C12 myotubes we found some codistribution of aciculin with clusters of acetylcholine receptors, suggesting its presence at neuromuscular junctions. However, we did not detect any significant concentration of aciculin at neuromuscular junctions in both embryonic and adult skeletal muscle. Taken together, our data show that aciculin expression in skeletal muscle is differentiation-dependent and upregulated during muscle development, and that this novel cytoskeletal protein is a component of various cell-matrix adherens junctions in muscle cells.

Endotoxin Alteration of the Mucopolysaccharide Blood Vessel Coating in Rats

1974 ◽  
Vol 32 ◽  
pp. 148-149
Author(s):  
D. E. Philpott ◽  
A. Takahashi
Keyword(s):  
Skeletal Muscle ◽  
Endothelial Cells ◽  
Salivary Gland ◽  
Carotid Artery ◽  
Basement Membrane ◽  
Coronary Vessels ◽  
Ruthenium Red ◽  
E Coli ◽  
Old Rats ◽  
The Brain

Two month, eight month and two year old rats were treated with 10 or 20 mg/kg of E. Coli endotoxin I. P. The eight month old rats proved most resistant to the endotoxin. During fixation the aorta, carotid artery, basil arartery of the brain, coronary vessels of the heart, inner surfaces of the heart chambers, heart and skeletal muscle, lung, liver, kidney, spleen, brain, retina, trachae, intestine, salivary gland, adrenal gland and gingiva were treated with ruthenium red or alcian blue to preserve the mucopolysaccharide (MPS) coating. Five, 8 and 24 hrs of endotoxin treatment produced increasingly marked capillary damage, disappearance of the MPS coating, edema, destruction of endothelial cells and damage to the basement membrane in the liver, kidney and lung.

Ultra-Rapid Freezing of Isolated Skeletal Muscle Fibers

1977 ◽  
Vol 35 ◽  
pp. 576-577
Author(s):  
Joachim R. Sommer ◽  
Nancy R. Wallace
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Granular Material ◽  
Nuclear Envelope ◽  
Intracellular Calcium ◽  
Ruthenium Red ◽  
Threshold Concentration ◽  
Rapid Freezing ◽  
Frog Skeletal Muscle ◽  
Electrical Isolation

After Howell (1) had shown that ruthenium red treatment of fixed frog skeletal muscle caused collapse of the intermediate cisternae of the sarcoplasmic reticulum (SR), forming a pentalaminate structure by obi iterating the SR lumen, we demonstrated that the phenomenon involves the entire SR including the nuclear envelope and that it also occurs after treatment with other cations, including calcium (2,3,4).From these observations we have formulated a hypothesis which states that intracellular calcium taken up by the SR at the end of contraction causes the M rete to collapse at a certain threshold concentration as the first step in a subsequent centrifugal zippering of the free SR toward the junctional SR (JSR). This would cause a) bulk transport of SR contents, such as calcium and granular material (4) into the JSR and, b) electrical isolation of the free SR from the JSR.

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

How to sample the entire length of a single muscle fiber quick-frozen after electrical point stimulation for high resolution EM

1992 ◽  
Vol 50 (1) ◽  
pp. 776-777
Author(s):  
Joachim R. Sommer ◽  
Teresa High ◽  
Betty Scherer ◽  
Isaiah Taylor ◽  
Rashid Nassar
Keyword(s):  
Skeletal Muscle ◽  
High Resolution ◽  
Action Potential ◽  
Muscle Fiber ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Electrical Field Stimulation ◽  
Skeletal Muscle Fiber ◽  
Freeze Dried ◽  
Quick Freezing

We have developed a model that allows the quick-freezing at known time intervals following electrical field stimulation of a single, intact frog skeletal muscle fiber isolated by sharp dissection. The preparation is used for studying high resolution morphology by freeze-substitution and freeze-fracture and for electron probe x-ray microanlysis of sudden calcium displacement from intracellular stores in freeze-dried cryosections, all in the same fiber. We now show the feasibility and instrumentation of new methodology for stimulating a single, intact skeletal muscle fiber at a point resulting in the propagation of an action potential, followed by quick-freezing with sub-millisecond temporal resolution after electrical stimulation, followed by multiple sampling of the frozen muscle fiber for freeze-substitution, freeze-fracture (not shown) and cryosectionmg. This model, at once serving as its own control and obviating consideration of variances between different fibers, frogs etc., is useful to investigate structural and topochemical alterations occurring in the wake of an action potential.

Alterations in Ultrastructure of Skeletal Muscle From Newborn Guinea Pigs Following in Utero Exposure to Ethanol

1985 ◽  
Vol 43 ◽  
pp. 686-687
Author(s):  
C. Uphoff ◽  
C. Nyquist-Battie ◽  
T.B. Cole
Keyword(s):  
Skeletal Muscle ◽  
Guinea Pigs ◽  
Muscle Development ◽  
In Utero ◽  
Ethanol Exposure ◽  
Prenatally Exposed ◽  
Chronic Alcoholic ◽  
Test Kit ◽  
Food And Water Intake ◽  
Post Intubation

Ultrastructural alterations of skeletal muscle have been observed in adult chronic alcoholic patients. However, no such study has been performed on individuals prenatally exposed to ethanol. In order to determine if ethanol exposure in utero in the latter stages of muscle development was deleterious, skeletal muscle was obtained from newborn guinea pigs treated in the following manner. Six Hartly strain pregnant guinea pigs were randomly assigned to either the ethanol or the pair-intubated groups. Twice daily the 3 ethanol-treated animals were intubated with Ensure (Ross Laboratories) liquid diet containing 30% ethanol (6g/Kg pre-pregnant body weight per day) from day 35 of gestation until parturition at day 70±1 day. Serum ethanol levels were determined at 1 hour post-intubation by the Sigma alcohol test kit. For pair-intubation the Ensure diet contained sucrose substituted isocalorically for ethanol. Both food and water intake were monitored.

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