Correlations between Troponin-T and Myosin Heavy Chain Isoforms in Normal and Transforming Rabbit Muscle Fibers

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.

Download Full-text

Correlation between myofibrillar ATPase activity and myosin heavy chain composition in rabbit muscle fibers

Histochemistry ◽

10.1007/bf00492341 ◽

1986 ◽

Vol 86 (1) ◽

pp. 19-23 ◽

Cited By ~ 141

Author(s):

R. S. Staron ◽

D. Pette

Keyword(s):

Atpase Activity ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Muscle Fibers ◽

Rabbit Muscle ◽

Myofibrillar Atpase ◽

Myofibrillar Atpase Activity ◽

Chain Composition ◽

Myosin Heavy Chain Composition

Download Full-text

Muscle fibers of dog thyroarytenoid muscle: Coexpression of multiple myosin heavy chain isoforms

Otolaryngology ◽

10.1016/s0194-5998(97)80388-9 ◽

1997 ◽

Vol 117 (2) ◽

pp. P183-P184

Author(s):

Y WU ◽

M BAKER ◽

R CRUMLEY ◽

R BLANKS ◽

V CAIOZZO

Keyword(s):

Myosin Heavy Chain ◽

Heavy Chain ◽

Muscle Fibers ◽

Myosin Heavy Chain Isoforms ◽

Thyroarytenoid Muscle

Download Full-text

Single-fiber myosin heavy chain polymorphism: how many patterns and what proportions?

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00646.2002 ◽

2003 ◽

Vol 285 (3) ◽

pp. R570-R580 ◽

Cited By ~ 59

Author(s):

Vincent J. Caiozzo ◽

Michael J. Baker ◽

Karen Huang ◽

Harvey Chou ◽

Ya Zhen Wu ◽

...

Keyword(s):

Skeletal Muscle ◽

Myosin Heavy Chain ◽

Heavy Chain ◽

Muscle Fibers ◽

Myosin Heavy Chain Isoforms ◽

Single Fiber ◽

Myosin Heavy Chain Isoform ◽

Skeletal Muscle Fibers ◽

Velocity Relationship ◽

Force Velocity

Previous studies have reported the existence of skeletal muscle fibers that coexpress multiple myosin heavy chain isoforms. These surveys have usually been limited to studying the polymorphic profiles of skeletal muscle fibers from a limited number of muscles (i.e., usually <4). Additionally, few studies have considered the functional implications of polymorphism. Hence, the primary objective of this study was to survey a relatively large number of rat skeletal muscle/muscle regions and muscle fibers ( n≈ 5,000) to test the hypothesis that polymorphic fibers represent a larger fraction of the total pool of fibers than do so-called monomorphic fibers, which express only one myosin heavy chain isoform. Additionally, we used Hill's statistical model of the force-velocity relationship to differentiate the functional consequences of single-fiber myosin heavy chain isoform distributions found in these muscles. The results demonstrate that most muscles and regions of rodent skeletal muscles contain large proportions of polymorphic fibers, with the exception of muscles such as the slow soleus muscle and white regions of fast muscles. Several muscles were also found to have polymorphic profiles that are not consistent with the I↔IIA↔IIX↔IIB scheme of muscle plasticity. For instance, it was found that the diaphragm muscle normally contains I/IIX fibers. Functionally, the high degree of polymorphism may 1) represent a strategy for producing a spectrum of contractile properties that far exceeds that simply defined by the presence of four myosin heavy chain isoforms and 2) result in relatively small differences in function as defined by the force-velocity relationship.

Download Full-text

Functional Effects of the H1-Helix of Rat Cardiac Troponin T on Crossbridge Detachment Rate is Differently Modulated by α- and β-Myosin Heavy Chain Isoforms

Biophysical Journal ◽

10.1016/j.bpj.2014.11.3245 ◽

2015 ◽

Vol 108 (2) ◽

pp. 596a ◽

Cited By ~ 3

Author(s):

John J. Michael ◽

Murali Chandra

Keyword(s):

Myosin Heavy Chain ◽

Heavy Chain ◽

Cardiac Troponin ◽

Troponin T ◽

Myosin Heavy Chain Isoforms ◽

Cardiac Troponin T ◽

Detachment Rate

Download Full-text

Myosin heavy chain isoforms of human muscle after short-term spaceflight

Journal of Applied Physiology ◽

10.1152/jappl.1995.78.5.1740 ◽

1995 ◽

Vol 78 (5) ◽

pp. 1740-1744 ◽

Cited By ~ 71

Author(s):

M. Y. Zhou ◽

H. Klitgaard ◽

B. Saltin ◽

R. R. Roy ◽

V. R. Edgerton ◽

...

Keyword(s):

Myosin Heavy Chain ◽

Heavy Chain ◽

Space Shuttle ◽

Vastus Lateralis ◽

Muscle Fibers ◽

Rapid Change ◽

Myosin Heavy Chain Isoforms ◽

Single Fiber ◽

Type I ◽

Type Ii

The influence of microgravity on the myosin phenotype of skeletal muscle fibers in the vastus lateralis of eight crew members was studied before and after 5-day (n = 3) and 11-day (n = 5) spaceflights (space shuttle flights: STS-32, -33 and -34). Single-fiber electrophoresis analyses showed that the proportion of fibers expressing only slow (type I) myosin heavy chain (MHC) in the vastus lateralis was significantly lower after than before 11 days of spaceflight. Although the family of type II MHC isoforms was elevated post- compared with preflight, the distribution among the isoforms of type II MHC was not statistically different. Based on monoclonal and polyclonal antibodies specific for three adult MHC isoforms and single-fiber electrophoresis, approximately 3% of the fibers analyzed coexpressed all three adult MHC isoforms. The results from immunohistochemical staining with two different sets of antibodies indicate a reduction in the percentage of fibers expressing type I MHC as a result of spaceflight. The mean difference, however, was significant only when the fibers were categorized simply as type I or II. These changes appeared to be highly individualized among the astronauts. These results suggest that a rapid change in MHC isoform expression can occur in some muscle fibers after a relatively brief exposure to spaceflight.

Download Full-text