FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
Cell. 2012 Feb 3;148(3):502-14. doi: 10.1016/j.cell.2012.01.007.
Dynein at the cortex contributes to microtubule-based positioning processes such as spindle positioning during embryonic cell division and centrosome positioning during fibroblast migration. To investigate how cortical dynein interacts with microtubule ends to generate force and how this functional association impacts positioning, we have reconstituted the 'cortical' interaction between dynein and dynamic microtubule ends in an in vitro system using microfabricated barriers. We show that barrier-attached dynein captures microtubule ends, inhibits growth, and triggers microtubule catastrophes, thereby controlling microtubule length. The subsequent interaction with shrinking microtubule ends generates pulling forces up to several pN. By combining experiments in microchambers with a theoretical description of aster mechanics, we show that dynein-mediated pulling forces lead to the reliable centering of microtubule asters in simple confining geometries. Our results demonstrate the intrinsic ability of cortical microtubule-dynein interactions to regulate microtubule dynamics and drive positioning processes in living cells.
皮层中的动力蛋白有助于基于微管的定位过程，例如胚胎细胞分裂过程中的纺锤体定位和成纤维细胞迁移过程中的中心体定位。为了研究皮层动力蛋白如何与微管末端相互作用产生力，以及这种功能关联如何影响定位，我们使用微加工障碍物在体外系统中重新构建了动力蛋白和动态微管末端之间的“皮层”相互作用。我们表明，附着在障碍物上的动力蛋白捕获微管末端，抑制生长并引发微管灾难，从而控制微管长度。随后与收缩的微管末端相互作用会产生高达数皮牛顿的拉力。通过将微腔中的实验与星状机械的理论描述相结合，我们表明，动力蛋白介导的拉力导致微管星在简单的约束几何形状中可靠地居中。我们的结果表明，皮层微管-动力蛋白相互作用具有内在的调节微管动力学和驱动活细胞定位过程的能力。
