Myosin cross-bridge kinetics slow at longer muscle lengths during isometric contractions in intact soleus from mice
Myosin cross-bridge kinetics slow at longer muscle lengths during isometric contractions in intact soleus from mice
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小鼠完整比目鱼肌等长收缩期间，肌球蛋白跨桥动力学在较长肌肉长度下减慢
DOI：
10.1098/rspb.2020.2895
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Tanner, Bertrand C.
中科院分区：
文献类型：
--
作者：
Fenwick, Axel J.;Lin, David C.;Tanner, Bertrand C.
肌肉收缩是由肌凝蛋白和肌动蛋白之间产生的跨桥相互作用引起的。跨桥循环动力学是基本收缩特性的基础，如主动力的产生和能量的利用。在分子水平上影响过桥动力学的因素通过肌节、细胞和组织传播，以调节整个肌肉功能。相反，运动和肌肉长度的变化可以在分子水平上影响过桥动力学。减少的单分子和单纤维实验表明，增加交叉桥上的应变可能会减慢它们的循环速度，延长它们的附着时间。然而，这些依赖于应变的循环机制是否在完整的肌肉组织中持续存在，这包括更复杂的组织和被动元素，仍然不清楚。为了研究这种多尺度关系，我们采用了传统的步进拉伸方案，用于小鼠比目鱼肌在等长强直收缩期间的拉伸，从而对完整骨骼肌的长度依赖性过桥动力学进行了新的估计。与最佳肌肉长度（Lo）相比，我们发现在90%的肌肉长度（较短）时桥间脱离率增加了约20%，在110%的肌肉长度（较长）时桥间脱离率下降了约20%。这些数据表明，在完整的等距收缩过程中，过桥动力学随全肌肉长度的变化而变化，这可能内在地调节力的产生和能量学，并表明全肌肉功能和过桥活性之间存在多尺度反馈途径。
Muscle contraction results from force-generating cross-bridge interactions between myosin and actin. Cross-bridge cycling kinetics underlie fundamental contractile properties, such as active force production and energy utilization. Factors that influence cross-bridge kinetics at the molecular level propagate through the sarcomeres, cells and tissue to modulate whole-muscle function. Conversely, movement and changes in the muscle length can influence cross-bridge kinetics on the molecular level. Reduced, single-molecule and single-fibre experiments have shown that increasing the strain on cross-bridges may slow their cycling rate and prolong their attachment duration. However, whether these strain-dependent cycling mechanisms persist in the intact muscle tissue, which encompasses more complex organization and passive elements, remains unclear. To investigate this multi-scale relationship, we adapted traditional step-stretch protocols for use with mouse soleus muscle during isometric tetanic contractions, enabling novel estimates of length-dependent cross-bridge kinetics in the intact skeletal muscle. Compared to rates at the optimal muscle length (Lo), we found that cross-bridge detachment rates increased by approximately 20% at 90% ofLo(shorter) and decreased by approximately 20% at 110% ofLo(longer). These data indicate that cross-bridge kinetics vary with whole-muscle length during intact, isometric contraction, which could intrinsically modulate force generation and energetics, and suggests a multi-scale feedback pathway between whole-muscle function and cross-bridge activity.
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DOI：
10.1098/rspb.2011.1304
发表时间：
2012-03-07
影响因子：
4.7
作者：
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影响因子：
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作者：
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影响因子：
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DOI：
10.1016/s0006-3495(95)80380-2
发表时间：
1995
期刊：
Biophysical journal.
影响因子：
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作者：
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通讯作者：
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影响因子：
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