Polarized epithelial cell migration depends on rear end stress fiber tension
R. Merkel Hoffmann
|Titel||Polarized epithelial cell migration depends on rear end stress fiber tension|
|Ort||FMC - Filaments, Membranes, Cells - and their Interactions, Jülich, Germany, January 28-31, 2018.|
Actin stress fibers (SFs) play a central role in cell adhesion and migration. Recently laser ablation has become a popular tool to understand mechanical properties of actin SFs and to measure forces generated by single or multiple actin SFs in non-locomoting or patterned cells, but still less is known about the role of individual actin SFs in migrating cells. Here we perform laser nanosurgery combined with live-cell microscopy and traction force microscopy (TFM) to investigate contribution of the actin ventral SF at the rear end of the polarized cell to cell polarity, migration and force transmission in human keratinocytes (NHEK). We show that severing of this highly contractile SF results in subsequent disassembly of the following proteins from the cut ends: α-actinin, zyxin and myosin II, and fast replacement of the severed SF by new thin actin fiber. Furthermore, within the following 60 s we observed growth of lamellipodial protrusion at the cell rear end, finally leading to loss of polarity, cell shape reorganization and temporal stop of migration. Additionally TFM demonstrated that disruption of the actin ventral SF induced immediate local relaxation of the underlying prestressed substrate and significant force adaptation under the whole cell body on the long term after the laser ablation. Altogether, these data show the essential role of the ventral SF at the cell tail in maintenance of cell polarity, migration and force generation.