Direct, high-resolution measurement of furrow stiffening during division of adherent cells

Abstract

It is unclear whether cell division is driven by cortical relaxation outside the equatorial region or cortical contractility within the developing furrow alone. To approach this question, a technique is required that can monitor spatially-resolved changes in cortical stiffness with good time resolution. We employed atomic force microscopy (AFM), in force-mapping mode, to track dynamic changes in the stiffness of the cortex of adherent cultured cells along a single scan-line during M phase, from metaphase to cytokinesis. Video microscopy, which we used to correlate the AFM data with mitotic events identified by light microscopy, indicated that the AFM force-mapping technique does not perturb dividing cells. Here we show that cortical stiffening occurs over the equatorial region about 160 seconds before any furrow appears, and that this stiffening markedly increases as the furrow starts. By contrast, polar relaxation of cells does not seem to be an obligatory event for cell division to occur.

Measuring cell adhesion forces during the cell cycle by force spectroscopy

“…II C͒ suggested that G 2 M and native mitotic cells were stiffer than cells in the other phases. The increased stiffness of mitotic cells has been reported by other authors 32,33 and is associated with a reorganization of the cytoskeleton ͑Fig. 4͒.…”

Imaging and measuring the rituximab-induced changes of mechanical properties in B-lymphoma cells using atomic force microscopy

“…The prerequisite of imaging living cells in fluids is to attach them onto a flat support (such as glass) to withstand the lateral force exerted by the scanning tip. For those adherent cells, the most commonly used method is to directly culture them on a glass support for about 1-2 days and these cells can adhere to the support tightly [24]. Sometimes in order to enhance the cell adherence, adhesion proteins such as poly-L-lysine are coated onto the substrate [25].…”

Force measurements with the atomic force microscope: Technique, interpretation and applications

“…Sacrificing two-dimensional resolution by using single line scans can increase time resolution while still capturing spatial information in one direction. The group of Radmacher used this trick to study the dynamics of 3T3 fibroblasts [1216], MTLn3 cells [1217], and potorous triactylis kidney cells [1218].…”