Titin force is enhanced in actively stretched skeletal muscle
Titin force is enhanced in actively stretched skeletal muscle
复制标题
主动拉伸的骨骼肌中肌联力增强
DOI：
10.1242/jeb.105361
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发表时间：
2014
影响因子：
2.8
通讯作者：
W. Herzog
中科院分区：
文献类型：
--
作者：
K. Powers;G. Schappacher;A. Jinha;T. Leonard;K. Nishikawa;W. Herzog
肌肉收缩的滑丝理论被广泛接受为肌肉在激活过程中产生力的手段。在该理论的约束下，肌肉激活过程中产生的等长稳态力与纤维重叠量成正比。我们实验室先前的研究表明，肌原纤维中肌蛋白基力的增强被主动拉伸到超过纤维重叠的长度。这种现象不能用滑丝理论来解释。本研究的目的是进一步研究活跃拉伸时titin的增强状态。具体来说，我们证实这种增强的力状态是在小鼠模型中观察到的，并量化了钙对这种力的贡献。在主动拉伸分离的肌原纤维时，titin基力增加到被动力的四倍。在两种不同的动物模型中已经证明了增强的titin-based力，这表明在主动拉伸期间titin-based力的调节是骨骼肌的固有特性。我们的研究结果还表明，15%的titin增强状态可归因于钙对蛋白质的直接作用，可能是钙结合到PEVK片段的富e区域和选定的Ig结构域片段时蛋白质的硬化。我们认为，剩余的85%的无法解释的额外力是由titin与细丝结合造成的。随着这种增强的力量在小鼠模型中得到证实，未来的研究将旨在阐明在主动拉伸的肌节中提出的titin-thin filament相互作用。
The sliding filament theory of muscle contraction is widely accepted as the means by which muscles generate force during activation. Within the constraints of this theory, isometric, steady-state force produced during muscle activation is proportional to the amount of filament overlap. Previous studies from our laboratory demonstrated enhanced titin-based force in myofibrils that were actively stretched to lengths which exceeded filament overlap. This observation cannot be explained by the sliding filament theory. The aim of the present study was to further investigate the enhanced state of titin during active stretch. Specifically, we confirm that this enhanced state of force is observed in a mouse model and quantify the contribution of calcium to this force. Titin-based force was increased by up to four times that of passive force during active stretch of isolated myofibrils. Enhanced titin-based force has now been demonstrated in two distinct animal models, suggesting that modulation of titin-based force during active stretch is an inherent property of skeletal muscle. Our results also demonstrated that 15% of the enhanced state of titin can be attributed to direct calcium effects on the protein, presumably a stiffening of the protein upon calcium binding to the E-rich region of the PEVK segment and selected Ig domain segments. We suggest that the remaining unexplained 85% of this extra force results from titin binding to the thin filament. With this enhanced force confirmed in the mouse model, future studies will aim to elucidate the proposed titin–thin filament interaction in actively stretched sarcomeres.
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影响因子：
3.4
作者：
Yamasaki, R;Berri, M;Granzier, H
通讯作者：
Granzier, H
DOI：
--
发表时间：
2001-05
期刊：
The Journal of experimental biology
影响因子：
--
作者：
Thomas J. Burkholder;Richard L Lieber
通讯作者：
Thomas J. Burkholder;Richard L Lieber
影响因子：
3.5
作者：
Huebsch, KA;Kudryashova, E;Cox, GA
通讯作者：
Cox, GA
影响因子：
3.4
作者：
GRANZIER, HL;IRVING, TC
通讯作者：
IRVING, TC