Computer simulation of flagellar movement VIII: Coordination of dynein by local curvature control can generate helical bending waves
Computer simulation of flagellar movement VIII: Coordination of dynein by local curvature control can generate helical bending waves
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DOI：
10.1002/cm.10067
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发表时间：
2002-10-01
影响因子：
--
通讯作者：
Brokaw, CJ
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文献类型：
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作者：
Brokaw, CJ
用一种可以在三维空间弯曲的鞭毛模型进行了计算机模拟。动力蛋白激活的一种模式，在这种模式中，动力蛋白的活动区沿着每个双线传播，相邻双线之间的相移约为1/9波长，将产生螺旋弯曲波。这种模式可以被称为“双重同时性”。模拟结果表明，在动力蛋白的激活由每个外部双微管的曲率局部控制的模型轴丝中，双线同时性可以自发地发生。在这个模型中，动力蛋白既可以作为曲率传感器，也可以作为发动机。双线同时性和由此产生的螺旋弯曲图案的手性由双线上的动力素产生的力矩和滑动方向与该双线的控制曲率方向之间的角度差来调节。产生螺旋弯曲波的鞭毛在抵抗外部粘性阻力时会经历扭曲的时刻。在高粘度下，除非扭转阻力比先前估计的大，否则螺旋弯曲将被扭曲显著地改变。为了使鞭毛产生有效推进精子所需的平面弯曲波，自发的双重同时性必须被修改或覆盖。在三维鞭毛模型中，通过对每一对偶的控制曲率方向进行适当的规定，可以实现平面弯曲。然而，实验观察表明，这种“硬连线”的解决方案并不适合真正的鞭毛。细胞运动。细胞骨架53：103-124,2002。(C)2002年Wiley-Liss，Inc.
Computer simulations have been carried out with a model flagellum that can bend in three dimensions. A pattern of dynein activation in which regions of dynein activity propagate along each doublet, with a phase shift of approximately 1/9 wavelength between adjacent doublets, will produce a helical bending wave. This pattern can be termed "doublet metachronism." The simulations show that doublet metachronism can arise spontaneously in a model axoneme in which activation of dyneins is controlled locally by the curvature of each outer doublet microtubule. In this model, dyneins operate both as sensors of curvature and as motors. Doublet metachronism and the chirality of the resulting helical bending pattern are regulated by the angular difference between the direction of the moment and sliding produced by dyneins on a doublet and the direction of the controlling curvature for that doublet. A flagellum that is generating a helical bending wave experiences twisting moments when it moves against external viscous resistance. At high viscosities, helical bending will be significantly modified by twist unless the twist resistance is greater than previously estimated. Spontaneous doublet metachronism must be modified or overridden in order for a flagellum to generate the planar bending waves that are required for efficient propulsion of spermatozoa. Planar bending can be achieved with the three-dimensional flagellar model by appropriate specification of the direction of the controlling curvature for each doublet. However, experimental observations indicate that this "hard-wired" solution is not appropriate for real flagella. Cell Motil. Cytoskeleton 53:103-124, 2002. (C) 2002 Wiley-Liss, Inc.