Simulation of Cyclic Dynein-Driven Sliding, Splitting, and Reassociation in an Outer Doublet Pair
Simulation of Cyclic Dynein-Driven Sliding, Splitting, and Reassociation in an Outer Doublet Pair
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DOI：
10.1016/j.bpj.2009.09.022
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发表时间：
2009-12-02
影响因子：
3.4
通讯作者：
Brokaw, Charles J.
中科院分区：
文献类型：
--
作者：
Brokaw, Charles J.
在衣藻鞭毛部分解离后获得的外层双体对中，青山和神谷观察到了动力蛋白驱动的滑动、二重体分离、二重体重新结合和恢复滑动的规律循环。在本文介绍的工作中，基于以前对微管振荡弯曲的模拟的计算机编程被扩展到模拟双线对观测到的事件的周期。这些模拟证实了这种振荡的直接解释，即当双胞体分离时动力蛋白失活，重新结合后动力蛋白活动恢复。二联体之间依赖动力蛋白的“粘附力”增强了再结合作用。模拟使用了一个简单的数学模型来产生与速度相关的剪切力，并使用了一个独立的弹性模型来计算粘附力。在最大粘附力为最大剪切力的36%的情况下，获得了真实的结果。一对二重线之间的分离是屈曲不稳定性的结果，它也启动了一段均匀滑动的周期，从而扩大了分离。类似的不稳定性可能触发鞭毛弯曲循环中的滑动启动事件。
A regular cycle of dynein-driven sliding, doublet separation, doublet reassociation, and resumption of sliding was previously observed by Aoyama and Kamiya in outer doublet pairs obtained after partial dissociation of Chlamydomonas flagella. In the work presented here, computer programming based on previous simulations of oscillatory bending of microtubules was extended to simulate the cycle of events observed with doublet pairs. These simulations confirm the straightforward explanation of this oscillation by inactivation of dynein when doublets separate and resumption of dynein activity after reassociation. Reassociation is augmented by a dynein-dependent "adhesive force" between the doublets. The simulations used a simple mathematical model to generate velocity-dependent shear force, and an independent elastic model for adhesive force. Realistic results were obtained with a maximum adhesive force that was 36% of the maximum shear force. Separation between a pair of doublets is the result of a buckling instability that also initiates a period of uniform sliding that enlarges the separation. A similar instability may trigger sliding initiation events in flagellar bending cycles.