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Cell mechanics: definitely very surprising

Cells move, deform and divide. CEA-Irig researchers are gaining a better and better understanding of how it works. To do this, they have "cut" the contractile cables very precisely with a laser.

Published on 1 December 2020

Mechanical forces exerted by cells play a crucial role on the proper functioning of organs by controlling notably their shape and development. At the microscopic level, each cell has an internal framework, the cytoskeleton, made up of specialized proteins that ensure the generation and transmission of cellular forces to their environment. Among these proteins, actin forms filaments that are reorganized by the action of molecular motors called myosins, generating contractile cables called stress fibers that resemble elastic springs stretched between two anchoring points. Although these structures are widely recognized as being involved in force generation at the molecular level, the mechanism by which forces are generated and distributed at the entire cell-level remains unknown.

 In order to characterize the production of forces in these contractile cables, IRIG researchers cut them by making a precise incision using a laser beam.

This manoeuvre led to an unexpected result: the total cell force was barely affected, showing that other structures in the cytoskeleton were at work to generate and transmit force at the cell level. The same technique was then used to produce a cut in the actin network found along the cell membrane, a network previously considered as passive. By subsequently modeling the contribution of the entire actin network through physical parameters, the researchers understood that the entire sub-membrane actin network was also contributing to force production and not only the stress fibers. Using several complementary techniques to improve the resolution of the cytoskeleton images, the researchers also discovered that the stress fibers, far from being isolated structures, were in fact completely entangled in the surrounding actin network lining the membrane.


Interdisciplinary Research Institute of Grenoble (IRIG - CEA/CNRS/Université Grenoble Alpes)

Courant Institute and Department of Biology, New York University
​European Molecular Biology Laboratory (EMBL), Heidelberg
​NeuroCyto, Institute of NeuroPhysiopathology (INP), CNRS, Aix Marseille Université

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