Sammak P J, Borisy G G
Laboratory of Molecular Biology, University of Wisconsin-Madison 53706.
Nature. 1988 Apr 21;332(6166):724-6. doi: 10.1038/332724a0.
The study of cell locomotion is fundamental to such diverse processes as embryonic development, wound healing and metastasis. Since microtubules play a role in establishing the leading lamellum and maintaining cell polarity, it is important to understand their dynamic behaviour. In vitro, subunits exchange with polymer by treadmilling and by dynamic instability. Disassembly events can be complete (catastrophic) or incomplete (tempered). In vivo, microtubules are in dynamic equilibrium with subunits with a half-time for turnover of 4-20 min. Microtubules grow by elongation of their ends and are replaced one by one with turnover being most rapid at the periphery. Although previous results are consistent with dynamic instability, we sought to directly test the mechanism of turnover. Direct observations of fluorescent microtubules in the fibroblast lamellum show that individual microtubules undergo rounds of assembly and disassembly from the same end. Reorganization of the microtubule network occurs by a tempered mode of dynamic instability.
细胞运动的研究对于胚胎发育、伤口愈合和转移等多种不同过程至关重要。由于微管在建立前缘片层和维持细胞极性方面发挥作用，了解其动态行为很重要。在体外，亚基通过踏车行为和动态不稳定性与聚合物进行交换。解聚事件可以是完全的（灾难性的）或不完全的（缓和的）。在体内，微管与亚基处于动态平衡，周转半衰期为4 - 20分钟。微管通过其末端的延长而生长，并逐个被替换，周转在周边最为迅速。尽管先前的结果与动态不稳定性一致，但我们试图直接测试周转机制。对成纤维细胞片层中荧光微管的直接观察表明，单个微管从同一末端经历组装和解聚的循环。微管网络的重组通过动态不稳定性的缓和模式发生。
