MHC and sarcoplasmic reticulum protein isoforms in functionally overloaded cat plantaris muscle fibers

1996 ◽  
Vol 80 (4) ◽  
pp. 1296-1303 ◽  
Author(s):  
R. J. Talmadge ◽  
R. R. Roy ◽  
G. R. Chalmers ◽  
V. R. Edgerton
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Heavy Chain ◽  
Muscle Fibers ◽  
Protein Isoforms ◽  
Type I ◽  
Single Muscle ◽  
Plantaris Muscle ◽  
Plasmic Reticulum ◽  
Deep Region ◽  
Isoform Expression

To determine whether the adaptations in myosin heavy chain (MHC) isoform expression after functional overload (FO) are accompanied by commensurate adaptations in protein isoforms responsible for relaxation [sarco(endo)plasmic reticulum (SR) Ca(2+)-adenosinetriphosphatase (SERCA) and phospholamban (PHL)] in single muscle fibers, the isoforms of MHC and SERCA and the presence or absence of PHL were determined for cat plantaris fibers 3 mo after FO. In control plantaris the relative MHC isoform composition was 23% type I, 21% type IIa, and 56% type IIb. FO resulted in a shift toward slower isoforms (33% type I, 44% type IIa, and 23% type IIb). In the deep region of the plantaris the proportions of type I MHC and hybrid MHC fibers (containing type I and II MHCs) were 40 and 200% greater in FO cats, respectively. FO resulted in a 47% increase in the proportion of fibers containing only the slow SERCA isoform (SERCA2) and a 41% increase in the proportion of fibers containing PHL. The proportions of fibers containing type I MHC, SERCA2, and PHL in control and FO plantaris were linearly correlated. These data show that adaptations in MHC isoform expression are accompanied by commensurate adaptations in sarcoplasmic reticulum protein isoforms in single muscle fibers after FO.

Altered expression of skeletal muscle myosin isoforms in cancer cachexia

2002 ◽  
Vol 283 (5) ◽  
pp. C1376-C1382 ◽  
Author(s):  
Gary M. Diffee ◽  
Katherine Kalfas ◽  
Sadeeka Al-Majid ◽  
Donna O. McCarthy
Keyword(s):  
Muscle Atrophy ◽  
Cancer Cachexia ◽  
Muscle Wasting ◽  
Tumor Cell Line ◽  
Protein Isoforms ◽  
Type I ◽  
Myosin Isoforms ◽  
Skeletal Muscle Myosin ◽  
Altered Expression ◽  
Isoform Expression

Cachexia is commonly seen in cancer and is characterized by severe muscle wasting, but little is known about the effect of cancer cachexia on expression of contractile protein isoforms such as myosin. Other causes of muscle atrophy shift expression of myosin isoforms toward increased fast (type II) isoform expression. We injected mice with murine C-26 adenocarcinoma cells, a tumor cell line that has been shown to cause muscle wasting. Mice were killed 21 days after tumor injection, and hindlimb muscles were removed. Myosin heavy chain (MHC) and myosin light chain (MLC) content was determined in muscle homogenates by SDS-PAGE. Body weight was significantly lower in tumor-bearing (T) mice. There was a significant decrease in muscle mass in all three muscles tested compared with control, with the largest decrease occurring in the soleus. Although no type IIb MHC was detected in the soleus samples from control mice, type IIb comprised 19% of the total MHC in T soleus. Type I MHC was significantly decreased in T vs. control soleus muscle. MHC isoform content was not significantly different from control in plantaris and gastrocnemius muscles. These data are the first to show a change in myosin isoform expression accompanying muscle atrophy during cancer cachexia.

Distribution of myosin heavy chain isoforms in non-weight-bearing rat soleus muscle fibers

1996 ◽  
Vol 81 (6) ◽  
pp. 2540-2546 ◽  
Author(s):  
Robert J. Talmadge ◽  
Roland R. Roy ◽  
V. Reggie Edgerton
Keyword(s):  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
De Novo ◽  
Weight Bearing ◽  
Muscle Fibers ◽  
Myosin Heavy Chain Isoforms ◽  
Hindlimb Suspension ◽  
Type I ◽  
Rat Soleus Muscle

Talmadge, Robert J., Roland R. Roy, and V. Reggie Edgerton.Distribution of myosin heavy chain isoforms in non-weight-bearing rat soleus muscle fibers. J. Appl. Physiol. 81(6): 2540–2546, 1996.—The effects of 14 days of spaceflight (SF) or hindlimb suspension (HS) (Cosmos 2044) on myosin heavy chain (MHC) isoform content of the rat soleus muscle and single muscle fibers were determined. On the basis of electrophoretic analyses, there was a de novo synthesis of type IIx MHC but no change in either type I or IIa MHC isoform proportions after either SF or HS compared with controls. The percentage of fibers containing only type I MHC decreased by 26 and 23%, and the percentage of fibers with multiple MHCs increased from 6% in controls to 32% in HS and 34% in SF rats. Type IIx MHC was always found in combination with another MHC or combination of MHCs; i.e., no fibers contained type IIx MHC exclusively. These data suggest that the expression of the normal complement of MHC isoforms in the adult rat soleus muscle is dependent, in part, on normal weight bearing and that the absence of weight bearing induces a shift toward type IIx MHC protein expression in the preexisting type I and IIa fibers of the soleus.

scholarly journals Maximum Shortening Velocity and Myosin Heavy-chain Isoform Expression in Human Masseter Muscle Fibers

2001 ◽  
Vol 80 (9) ◽  
pp. 1845-1848 ◽  
Author(s):  
T.J. Morris ◽  
C.A. Branden ◽  
M.J. Horton ◽  
D.S. Carlson ◽  
J.J. Sciote
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Masseter Muscle ◽  
Muscle Fibers ◽  
Shortening Velocity ◽  
Myosin Heavy Chain Isoform ◽  
Isoform Expression

scholarly journals Innervation regulates myosin heavy chain isoform expression in developing skeletal muscle fibers

1996 ◽  
Vol 58 (1-2) ◽  
pp. 115-127 ◽  
Author(s):  
Bruno Lefeuvre ◽  
Fe´lix Crossin ◽  
Josiane Fontaine-Pe´rus ◽  
Everett Bandman ◽  
Marie-France Gardahaut
Keyword(s):  
Skeletal Muscle ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Muscle Fibers ◽  
Myosin Heavy Chain Isoform ◽  
Skeletal Muscle Fibers ◽  
Isoform Expression

The Molecular Diversity of Mammalian Muscle Fibers

Physiology ◽  
1993 ◽  
Vol 8 (4) ◽  
pp. 153-157 ◽  
Author(s):  
D Pette ◽  
RS Staron
Keyword(s):  
Molecular Diversity ◽  
Muscle Fibers ◽  
Protein Isoforms ◽  
Fiber Types ◽  
Mammalian Muscle ◽  
Neural Input ◽  
Multiple Protein ◽  
Isoform Expression ◽  
Dynamic Structures

Although muscle fibers can be separated into major groups, a spectrum of fiber types exists due to the expression of multiple protein isoforms. Also, muscle fibers are dynamic structures with the ability to change isoform expression in response to altered functional demands, changes in neural input, or hormonal signals.

Influence of overload on phenotypic remodeling in regenerated skeletal muscle

2001 ◽  
Vol 281 (5) ◽  
pp. C1686-C1694 ◽  
Author(s):  
A. X. Bigard ◽  
J. Zoll ◽  
F. Ribera ◽  
P. Mateo ◽  
H. Sanchez ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Lactate Dehydrogenase ◽  
Sarcoplasmic Reticulum ◽  
Heavy Chain ◽  
Type I ◽  
Similar Extent ◽  
Surgical Ablation ◽  
Control Of Gene Expression ◽  
Mechanical Overload

We studied the effects of 10 wk of functional overload on the expression of myosin heavy chain (MHC), sarcoplasmic reticulum Ca2+-ATPase isoforms (SERCA), and the activity of several metabolic enzymes in sham and regenerated plantaris muscles. Overload was accomplished by bilateral surgical ablation of its synergists 4 wk after right plantaris muscles regenerated after myotoxic infiltration. The overload-induced muscle enlargement was slightly less in regenerated than in sham muscles [28% ( P < 0.005) and 43% ( P < 0.001), respectively]. Overload led to an increase in type I MHC expression ( P < 0.01) to a similar extent in sham and regenerated plantaris, while the expected shift from type IIb to type IIa MHC was less marked in regenerated than in sham plantaris. The overload-induced decrease in the expression of the fast SERCA isoform and in the activity of the M subunit of lactate dehydrogenase occurred to a similar extent in sham and regenerated plantaris [66% ( P < 0.01) and 27% ( P < 0.005), respectively]. In conclusion, the lesser responses of muscle mass and fast MHC composition of regenerated plantaris to mechanical overload suggest an alteration of the transcriptional, translational, and/or posttranslational control of gene expression in regenerated muscle.

scholarly journals Contractile function of single muscle fibers after hindlimb unweighting in aged rats

1998 ◽  
Vol 84 (1) ◽  
pp. 229-235 ◽  
Author(s):  
L. V. Thompson ◽  
J. A. Shoeman
Keyword(s):  
Skeletal Muscle ◽  
Functional Properties ◽  
Contractile Function ◽  
Muscle Fibers ◽  
Type I ◽  
Single Muscle ◽  
Aged Rats ◽  
Active Force ◽  
Hindlimb Unweighting ◽  
Skeletal Muscle Fibers

Thompson, L. V., and J. A. Shoeman. Contractile function of single muscle fibers after hindlimb unweighting in aged rats. J. Appl. Physiol. 84(1): 229–235, 1998.—This investigation determined how muscle atrophy produced by hindlimb unweighting (HU) alters the contractile function of single muscle fibers from older animals (30 mo). After 1 wk of HU, small bundles of fibers were isolated from the soleus muscles and the deep region of the lateral head of the gastrocnemius muscles. Single glycerinated fibers were suspended between a motor lever and force transducer, functional properties were studied, and the myosin heavy chain (MHC) composition was determined electrophoretically. After HU, the diameter of type I MHC fibers of the soleus declined (88 ± 2 vs. 80 ± 4 μm) and reductions were observed in peak active force (47 ± 3 vs. 28 ± 3 mg) and peak specific tension (Po; 80 ± 5 vs. 56 ± 5 kN/m2). The maximal unloaded shortening velocity increased. The type I MHC fibers from the gastrocnemius showed reductions in diameter (14%), peak active force (41%), and Po (24%), whereas the type IIa MHC fibers showed reductions in peak active force and Po. Thus 1 wk of inactivity has a significant effect on the force-generating capacity of single skeletal muscle fibers from older animals in a fiber type-specific manner (type I MHC > type IIa MHC > type I-IIa MHC). The decline in the functional properties of single skeletal muscle fibers in the older animals appears to be more pronounced than what has been reported in younger animal populations.

Passive tension of rat skeletal soleus muscle fibers: effects of unloading conditions

2002 ◽  
Vol 92 (4) ◽  
pp. 1465-1472 ◽  
Author(s):  
Thierry Toursel ◽  
Laurence Stevens ◽  
Henk Granzier ◽  
Yvonne Mounier
Keyword(s):  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Muscle Fibers ◽  
Thick Filament ◽  
Muscle Stiffness ◽  
Hindlimb Unloading ◽  
Passive Tension ◽  
Tension Development ◽  
Isoform Expression

In this work we studied changes in passive elastic properties of rat soleus muscle fibers subjected to 14 days of hindlimb unloading (HU). For this purpose, we investigated the titin isoform expression in soleus muscles, passive tension-fiber strain relationships of single fibers, and the effects of the thick filament depolymerization on passive tension development. The myosin heavy chain composition was also measured for all fibers studied. Despite a slow-to-fast transformation of the soleus muscles on the basis of their myosin heavy chain content, no modification in the titin isoform expression was detected after 14 days of HU. However, the passive tension-fiber strain relationships revealed that passive tension of both slow and fast HU soleus fibers increased less steeply with sarcomere length than that of control fibers. Gel analysis suggested that this result could be explained by a decrease in the amount of titin in soleus muscle after HU. Furthermore, the thick filament depolymerization was found to similarly decrease passive tension in control and HU soleus fibers. Taken together, these results suggested that HU did not change titin isoform expression in the soleus muscle, but rather modified muscle stiffness by decreasing the amount of titin.

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