论文标题
囊泡的动力学被分子电动机驱动到封闭的收缩中
Dynamics of Vesicles Driven Into Closed Constrictions by Molecular Motors
论文作者
论文摘要
我们研究了膜囊泡转运到树突状棘的模型的动力学，该模型是由分子电机驱动的神经元中的球形细胞内室。我们减少了[Fai等人，在狭窄，盲骨狭窄的囊泡中的活性弹性水力动力学中提出的润滑模型。物理。 Rev. Fluids，2（2017），113601]到一个快速慢系统，在分析和数字上可拖动的方程式在过度抑制极限中等效于原始模型。该模型的主要参数是电动机的比率，该电动机更喜欢向树突状脊柱的头部推向更喜欢向相反方向推动的电动机的比率。我们在这些参数中执行数值分叉分析，发现稳态囊泡速度出现并通过几个鞍形节点分叉消失。这个过程使我们能够确定存在多个稳定速度的参数空间区域。我们通过直接计算显示，只能有足够接近囊泡直径比的单向运动。我们的分析预测了临界囊泡与脊柱直径比，在该比例从单向运动到双向运动的过渡与文献中囊泡轨迹的实验观察一致。
We study the dynamics of a model of membrane vesicle transport into dendritic spines, which are bulbous intracellular compartments in neurons driven by molecular motors. We reduce the lubrication model proposed in [Fai et al., Active elastohydrodynamics of vesicles in narrow, blind constrictions. Phys. Rev. Fluids, 2 (2017), 113601] to a fast-slow system, yielding an analytically and numerically tractable equation equivalent to the original model in the overdamped limit. The model's key parameters are the ratio of motors that prefer to push toward the head of the dendritic spine to the ratio of motors that prefer to push in the opposite direction. We perform a numerical bifurcation analysis in these parameters and find that steady-state vesicle velocities appear and disappear through several saddle-node bifurcations. This process allows us to identify the region of parameter space in which multiple stable velocities exist. We show by direct calculations that there can only be unidirectional motion for sufficiently close vesicle-to-spine diameter ratios. Our analysis predicts the critical vesicle-to-spine diameter ratio, at which there is a transition from unidirectional to bidirectional motion, consistent with experimental observations of vesicle trajectories in the literature.
