Institute for Atomic and Molecular Physics, Foundation for Fundamental Research on Matter, Amsterdam, The Netherlands.
Biophys J. 2010 Aug 4;99(3):726-35. doi: 10.1016/j.bpj.2010.05.026.
Microtubules (MTs) are dynamic protein polymers that change their length by switching between growing and shrinking states in a process termed dynamic instability. It has been suggested that the dynamic properties of MTs are central to the organization of the eukaryotic intracellular space, and that they are involved in the control of cell morphology, but the actual mechanisms are not well understood. Here, we present a theoretical analysis in which we explore the possibility that a system of dynamic MTs and MT end-tracking molecular motors is providing specific positional information inside cells. We compute the MT length distribution for the case of MT-length-dependent switching between growing and shrinking states, and analyze the accumulation of molecular motors at the tips of growing MTs. Using these results, we show that a transport system consisting of dynamic MTs and associated motor proteins can deliver cargo proteins preferentially to specific positions within the cell. Comparing our results with experimental data in the model organism fission yeast, we propose that the suggested mechanisms could play important roles in setting length scales during cellular morphogenesis.
微管（MTs）是动态的蛋白质聚合物，通过在称为动态不稳定性的过程中在生长和收缩状态之间切换来改变其长度。有人认为 MTs 的动态特性是真核细胞内空间组织的核心，并且它们参与了细胞形态的控制，但实际机制尚不清楚。在这里，我们提出了一种理论分析，其中我们探讨了动态 MTs 和 MT 末端跟踪分子马达系统在细胞内提供特定位置信息的可能性。我们针对生长和收缩状态之间的 MT 长度依赖性切换情况计算了 MT 长度分布，并分析了分子马达在生长 MT 尖端的积累情况。使用这些结果，我们表明由动态 MTs 和相关的马达蛋白组成的运输系统可以优先将货物蛋白输送到细胞内的特定位置。将我们的结果与模型生物裂殖酵母的实验数据进行比较，我们提出，所提出的机制可能在细胞形态发生过程中设定长度尺度方面发挥重要作用。
