The asymmetric distribution of microtubule (MT) dynamics in migrating cells is important for cell polarization, yet the underlying regulatory mechanisms remain underexplored. Here, we addressed this question by studying the role of the MT depolymerase, MCAK, in the highly persistent migration of RPE-1 cells. MCAK knockdown leads to slowed migration and poor directional movement. Fixed and live cell imaging revealed that MCAK knockdown results in excessive membrane ruffling as well as defects in cell polarization and the maintenance of a major protrusive front. Additionally, loss of MCAK increases the lifetime of focal adhesions by decreasing their disassembly rate. These functions correlate with a spatial distribution of MCAK activity, wherein activity is higher in the trailing edge of cells compared to the leading edge. Overexpression of Rac1 has a dominant effect over MCAK activity, placing it downstream or in a parallel pathway to MCAK function in migration. Together, our data support a model in which the polarized distribution of MCAK activity and subsequent differential regulation of MT dynamics contribute to cell polarity, centrosome positioning and focal adhesion dynamics that all help facilitate robust directional migration.

迁移细胞中微管 (MT) 动力学的不对称分布对于细胞极化很重要，但潜在的调节机制仍未得到充分探索。在这里，我们通过研究 MT 解聚酶 MCAK 在 RPE-1 细胞高度持久迁移中的作用来解决这个问题。MCAK 击倒导致迁移速度减慢和定向运动不佳。固定和活细胞成像显示 MCAK 敲低导致过度的膜褶皱以及细胞极化缺陷和主要突出前沿的维持。此外，MCAK 的损失通过降低其分解率来增加粘着斑的寿命。这些功能与 MCAK 活动的空间分布相关，其中与前缘相比，细胞后缘的活动更高。Rac1 的过表达对 MCAK 活性有显着影响，将其置于下游或与迁移中 MCAK 功能的平行途径中。总之，我们的数据支持一个模型，其中 MCAK 活性的极化分布和随后的 MT 动力学差异调节有助于细胞极性、中心体定位和粘着斑动力学，这些都有助于促进稳健的定向迁移。