School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK.
J Cell Sci. 2011 Aug 1;124(Pt 15):2642-53. doi: 10.1242/jcs.087965. Epub 2011 Jul 12.
When migrating mesenchymal cells collide, they exhibit a 'contact inhibition of locomotion' response that results in reversal of their front-rear polarity by extension of a new leading edge, which enables their migration away from the opposing contacted cell. The critical cytoskeletal rearrangements underpinning these mutual repulsion events are currently unknown. We found that during fibroblast cell-cell collisions, microtubules at the region of contact increase their frequency of catastrophe, their rates of shrinkage and growth, and concomitantly, a new microtubule array is established at a new leading edge. We show that Rho and ROCK activity is necessary for this repulsion response, and we observed increased microtubule stabilisation as a consequence of ROCK inhibition. Importantly, partial destabilisation of microtubules, by co-treatment with a low dose of nocodazole, restored microtubule dynamics to that of untreated cells and rescued contact inhibition of locomotion in ROCK-inhibited cells. Although there was an increase in microtubule growth or shrinkage rates in Y27632 cell-cell collisions, these failed to reach the same level of dynamicity compared with untreated collisions. Our data suggest that microtubule dynamics at contact sites must increase beyond a threshold for a cell to switch its front-rear polarity, and that microtubule stabilisation can lead to a failure of contact inhibition of locomotion.
当间质细胞迁移时发生碰撞，它们会表现出“接触性运动抑制”反应，通过延伸新的前缘来逆转前后极性，从而使它们从接触的对向细胞迁移。目前尚不清楚支持这些相互排斥事件的关键细胞骨架重排。我们发现，在成纤维细胞细胞碰撞过程中，接触区域的微管增加了其解聚的频率、收缩和生长的速度，同时，在新的前缘建立了新的微管阵列。我们表明 Rho 和 ROCK 活性对于这种排斥反应是必要的，并且我们观察到 ROCK 抑制导致微管稳定性增加。重要的是，用低剂量 nocodazole 进行部分微管去稳定化处理，恢复了未经处理的细胞的微管动力学，并挽救了 ROCK 抑制细胞中的接触性运动抑制。尽管 Y27632 细胞细胞碰撞中微管生长或收缩速度增加，但与未经处理的碰撞相比，它们未能达到相同的动态水平。我们的数据表明，接触部位的微管动力学必须增加到一定阈值以上，细胞才能切换前后极性，并且微管稳定性会导致接触性运动抑制失败。
