Myofiber-specific inhibition of TGFβ signaling protects skeletal muscle from injury and dystrophic disease in mice

The activity of glycogen synthase phosphatase in rat liver stems from the co-operation of two proteins, a cytosolic S-component and a glycogen-bound G-component. It is shown that both components possess synthase phosphatase activity. The G-component was partially purified from the enzyme-glycogen complex. Dissociative treatments, which increase the activity of phosphorylase phosphatase manyfold, substantially decrease the synthase phosphatase activity of the purified G-component. The specific inhibition of glycogen synthase phosphatase by phosphorylase a, originally observed in crude liver extracts, was investigated with purified liver synthase b and purified phosphorylase a. Synthase phosphatase is strongly inhibited, whether present in a dilute liver extract, in an isolated enzyme-glycogen complex, or as G-component purified therefrom. In contrast, the cytosolic S-component is insensitive to phosphorylase a. The activation of glycogen synthase in crude extracts of skeletal muscle is not affected by phosphorylase a from muscle or liver. Consequently we have studied the dephosphorylation of purified muscle glycogen synthase, previously phosphorylated with any of three protein kinases. Phosphorylase a strongly inhibits the dephosphorylation by the hepatic G-component, but not by the hepatic S-component or by a muscle extract. These observations show that the inhibitory effect of phosphorylase a on the activation of glycogen synthase depends on the type of synthase phosphatase.

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Specific inhibition of [3H] saxitoxin binding to skeletal muscle sodium channels by geographutoxin II, a polypeptide channel blocker.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)84540-4 ◽

1986 ◽

Vol 261 (14) ◽

pp. 6149-6152

Author(s):

Y Ohizumi ◽

H Nakamura ◽

J Kobayashi ◽

W A Catterall

Keyword(s):

Skeletal Muscle ◽

Sodium Channels ◽

Channel Blocker ◽

Specific Inhibition

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Double-blind study of metaxalone; use as skeletal-muscle relaxant

JAMA ◽

10.1001/jama.195.6.479 ◽

1966 ◽

Vol 195 (6) ◽

pp. 479-480 ◽

Cited By ~ 3

Author(s):

S. Diamond

Keyword(s):

Skeletal Muscle ◽

Muscle Relaxant ◽

Blind Study ◽

Double Blind Study ◽

Double Blind ◽

Skeletal Muscle Relaxant

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Endotoxin Alteration of the Mucopolysaccharide Blood Vessel Coating in Rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050755 ◽

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.

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Ultra-Rapid Freezing of Isolated Skeletal Muscle Fibers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080316 ◽

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.

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Electron Probe Analysis of Muscle

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100054583 ◽

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.

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