In vivo myosin step-size from zebrafish skeletal muscle
In vivo myosin step-size from zebrafish skeletal muscle
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DOI：
10.1098/rsob.160075
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发表时间：
2016-05-01
期刊：
影响因子：
5.8
通讯作者：
Wang, Yihua
中科院分区：
文献类型：
--
作者：
Burghardt, Thomas P.;Ajtai, Katalin;Wang, Yihua
肌凝蛋白将ATP自由能转化为肌动蛋白位移，从而产生能量收缩。在体内，肌凝蛋白侧链在自然条件下被翻译后修饰，可能影响功能。单个肌凝蛋白检测提供了“自下而上”的肌凝蛋白表征探测基本机制，没有集合观察固有的模糊性。宏观肌肉生理实验提供了明确的“自上而下”的表型特征，这是转化医学关注的问题。从斑马鱼胚胎模型中检测人体肌肉中的单个肌球蛋白，实现了自下而上和自上而下实验的雄心。在转基因斑马鱼骨骼肌中表达的光激活绿色荧光蛋白（GFP）标记的肌球蛋白轻链特异性地修饰了肌球蛋白杠杆臂。士的宁在活胚胎中诱导双侧尾巴肌肉同时收缩，使它们在活动时是等长的。高度倾斜的薄照明激发单个杠杆臂的GFP标签，其超分辨率方向从活动等距肌肉在覆盖许多转导周期的时间序列中测量。连续框架杠杆臂角位移与估计杠杆臂长度的乘积转化为步长。大约17%的2到7纳米之间的肌球蛋白活动步幅与力量冲程有关，因为它们超出了从松弛或atp耗尽（僵硬）肌肉中检测到的位移。
Muscle myosins transduce ATP free energy into actin displacement to power contraction. In vivo, myosin side chains are modified post-translationally under native conditions, potentially impacting function. Single myosin detection provides the 'bottom-up' myosin characterization probing basic mechanisms without ambiguities inherent to ensemble observation. Macroscopic muscle physiological experimentation provides the definitive 'top-down' phenotype characterizations that are the concerns in translational medicine. In vivo single myosin detection in muscle from zebrafish embryo models for human muscle fulfils ambitions for both bottom-up and top-down experimentation. A photoactivatable green fluorescent protein (GFP)-tagged myosin light chain expressed in transgenic zebrafish skeletal muscle specifically modifies the myosin lever-arm. Strychnine induces the simultaneous contraction of the bilateral tail muscles in a live embryo, causing them to be isometric while active. Highly inclined thin illumination excites the GFP tag of single lever-arms and its super-resolution orientation is measured from an active isometric muscle over a time sequence covering many transduction cycles. Consecutive frame lever-arm angular displacement converts to step-size by its product with the estimated lever-arm length. About 17% of the active myosin steps that fall between 2 and 7 nm are implicated as powerstrokes because they are beyond displacements detected from either relaxed or ATP-depleted (rigor) muscle.