Living cells constitute complex systems of formidable robustness, which
renders them extremely difficult to study : cells respond actively to
weak perturbations, and this does not allow to analyse it in a linear
framework. From a mechanical point of view, cells have developped the
capability to maintain and tune their shape and mechanical properties.
In order to do so, they possess a cytoskeleton made of semi-stiff
polymers, which they continuously re-shape, and which are bound together
(crosslinked) by transient molecular bonds, lasting for seconds only.
Also, other molecular bonds are indeed molecular motors, able to exert
contractile (pulling) forces within the cytoskeleton. These forces are
transmitted onto the cell’s environment, allowing it to deform its
substrate, and, through a yet unclear mechanism, to move.
Thanks to rheology experiments (figure a), we have demonstrated that a
simple mechanical model of the cytoskeleton, which expresses the link
between the stress and the strain rate , allows to predict the
cytoskeleton behaviour. This model is now ready to be enhanced and
exploited in order to understand cell motility. This can be done based
on experiments of cell migration, in which we measure simultaneously
cell displacements and forces they exert on the substrate.
Jocelyn Etienne <firstname.lastname@example.org>
Claude Verdier <email@example.com>