scholarly journals Influence of enhanced troponin C Ca2+-binding affinity on cooperative thin filament activation in rabbit skeletal muscle

2007 ◽  
Vol 583 (1) ◽  
pp. 337-350 ◽  
Author(s):  
Kareen L. Kreutziger ◽  
Todd E. Gillis ◽  
Jonathan P. Davis ◽  
Svetlana B. Tikunova ◽  
Michael Regnier
Keyword(s):  
Skeletal Muscle ◽  
Binding Affinity ◽  
Thin Filament ◽  
Troponin C ◽  
Rabbit Skeletal Muscle ◽  
Filament Activation

scholarly journals Dynamics of Thin-Filament Activation in Rabbit Skeletal Muscle Fibers Examined by Time-Resolved X-Ray Diffraction

2009 ◽  
Vol 96 (3) ◽  
pp. 1045-1055 ◽  
Author(s):  
Takumi Tamura ◽  
Jun'ichi Wakayama ◽  
Katsuaki Inoue ◽  
Naoto Yagi ◽  
Hiroyuki Iwamoto
Keyword(s):  
Skeletal Muscle ◽  
Thin Filament ◽  
Muscle Fibers ◽  
Rabbit Skeletal Muscle ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Skeletal Muscle Fibers ◽  
Filament Activation

scholarly journals Kinetics of a Ca(2+)-sensitive cross-bridge state transition in skeletal muscle fibers. Effects due to variations in thin filament activation by extraction of troponin C.

1991 ◽  
Vol 98 (2) ◽  
pp. 233-248 ◽  
Author(s):  
J M Metzger ◽  
R L Moss
Keyword(s):  
Steady State ◽  
Direct Effect ◽  
Thin Filament ◽  
Near Neighbor ◽  
Troponin C ◽  
Isometric Tension ◽  
Cross Bridge ◽  
Filament Activation ◽  
Kinetics Of ◽  
Partial Extraction

The rate constant of tension redevelopment (ktr; 1986. Proc. Natl. Acad. Sci. USA. 83:3542-3546) was determined at various levels of thin filament activation in skinned single fibers from mammalian fast twitch muscles. Activation was altered by (a) varying the concentration of free Ca2+ in the activating solution, or (b) extracting various amounts of troponin C (TnC) from whole troponin complexes while keeping the concentration of Ca2+ constant. TnC was extracted by bathing the fiber in a solution containing 5 mM EDTA, 10 mM HEPES, and 0.5 mM trifluoperazine dihydrochloride. Partial extraction of TnC resulted in a decrease in the Ca2+ sensitivity of isometric tension, presumably due to disruption of near-neighbor molecular cooperativity between functional groups (i.e., seven actin monomers plus associated troponin and tropomyosin) within the thin filament. Altering the level of thin filament activation by partial extraction of TnC while keeping Ca2+ concentration constant tested whether the Ca2+ sensitivity of ktr results from a direct effect of Ca2+ on cross-bridge state transitions or, alternatively, an indirect effect of Ca2+ on these transitions due to varying extents of thin filament activation. Results showed that the ktr-pCa relation was unaffected by partial extraction of TnC, while steady-state isometric tension exhibited the expected reduction in Ca2+ sensitivity. This finding provides evidence for a direct effect of Ca2+ on an apparent rate constant that limits the formation of force-bearing cross-bridge states in muscle fibers. Further, the kinetics of this transition are unaffected by disruption of near-neighbor thin filament cooperativity subsequent to extraction of TnC. Finally, the results support the idea that the steepness of the steady-state isometric tension-calcium relationship is at least in part due to mechanisms involving molecular cooperativity among thin filament regulatory proteins.

Disparate contributions of Tyr10and Tyr109to fluorescence intensity of rabbit skeletal muscle troponin C identified using a genetically engineered mutant

FEBS Letters ◽  
1994 ◽  
Vol 354 (2) ◽  
pp. 135-139 ◽  
Author(s):  
David Keleti ◽  
Venu G. Rao ◽  
Hong Su ◽  
Arvind B. Akella ◽  
Xiao-Ling Ding ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fluorescence Intensity ◽  
Troponin C ◽  
Genetically Engineered ◽  
Rabbit Skeletal Muscle

scholarly journals Ca2+ Regulation of Rabbit Skeletal Muscle Thin Filament Sliding: Role of Cross-Bridge Number

2003 ◽  
Vol 85 (3) ◽  
pp. 1775-1786 ◽  
Author(s):  
Bo Liang ◽  
Ying Chen ◽  
Chien-Kao Wang ◽  
Zhaoxiong Luo ◽  
Michael Regnier ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Thin Filament ◽  
Rabbit Skeletal Muscle ◽  
Cross Bridge ◽  
Muscle Thin Filament ◽  
Bridge Number

scholarly journals The effect of altered temperature on Ca2(+)-sensitive force in permeabilized myocardium and skeletal muscle. Evidence for force dependence of thin filament activation.

1990 ◽  
Vol 96 (6) ◽  
pp. 1221-1245 ◽  
Author(s):  
N K Sweitzer ◽  
R L Moss
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Muscle ◽  
Thin Filament ◽  
Calcium Sensitivity ◽  
Differential Sensitivity ◽  
Fiber Types ◽  
Tension Development ◽  
Maximum Tension ◽  
Filament Activation ◽  
Muscle Types

The effect of changes in temperature on the calcium sensitivity of tension development was examined in permeabilized cellular preparations of rat ventricle and rabbit psoas muscle. Maximum force and Ca2+ sensitivity of force development increased with temperature in both muscle types. Cardiac muscle was more sensitive to changes in temperature than skeletal muscle in the range 10-15 degrees C. It was postulated that the level of thin filament activation may be decreased by cooling. To investigate this possibility, troponin C (TnC) was partially extracted from both muscle types, thus decreasing the level of thin filament activation independent of temperature and, at least in skeletal muscle fibers, decreasing cooperative activation of the thin filament as well. TnC extraction from cardiac muscle reduced the calcium sensitivity of tension less than did extraction of TnC from skeletal muscle. In skeletal muscle the midpoint shift of the tension-pCa curve with altered temperature was greater after TnC extraction than in control fibers. Calcium sensitivity of tension development was proportional to the maximum tension generated in cardiac or skeletal muscle under all conditions studied. Based on these results, we conclude that (a) maximum tension-generating capability and calcium sensitivity of tension development are related, perhaps causally, in fast skeletal and cardiac muscles, and (b) thin filament activation is less cooperative in cardiac muscle than in skeletal muscle, which explains the differential sensitivity of the two fiber types to temperature and TnC extraction. Reducing thin filament cooperativity in skeletal muscle by TnC extraction results in a response to temperature similar to that of control cardiac cells. This study provides evidence that force levels in striated muscle influence the calcium binding affinity of TnC.

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