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Single-cell response to stiffness exhibits muscle-like behavior

D. Mitrossilis J. Fouchard A. Guiroy N. Desprat N. Rodriguez B. Fabry A. Asnacios

PNAS 106, 18243-18248 (2009) [Accès à la revue]

Nous avons mesuré ici la force de traction ainsi que l'énergie mécanique développées par une cellule vivante isolée (taille typique du centième de millimètre) pour déformer des substrats de différentes rigidités. Nous avons pu ainsi montrer que que l'adaptation cellulaire à son environnement reflétait des propriétés caractéristiques de l'adaptation musculaire à la charge. Finalement, la cellule, dotées de fibres contractiles semblables aux fibres musculaires, pourrait trouver son chemin au travers des tissus de différentes rigidités comme le cycliste adapte le développement de sa bicyclette au relief de son parcours.

Abstract: Living cells sense the rigidity of their environment and adapt their activity to it. In particular, cells cultured on elastic substrates align their shape and their traction forces along the direction of highest stiffness and preferably migrate towards stiffer regions. Although numerous studies investigated the role of adhesion complexes in rigidity sensing, less is known about the specific contribution of acto-myosin based contractility. Here we used a custom-made single-cell technique to measure the traction force as well as the speed of shortening of isolated myoblasts deflecting microplates of variable stiffness. The rate of force generation increased with increasing stiffness and followed a Hill force–velocity relationship. Hence, cell response to stiffness was similar to muscle adaptation to load, reflecting the force-dependent kinetics of myosin binding to actin. These results reveal an unexpected mechanism of rigidity sensing, whereby the contractile acto-myosin units themselves can act as sensors. This mechanism may translate anisotropy in substrate rigidity into anisotropy in cytoskeletal tension, and could thus coordinate local activity of adhesion complexes and guide cell migration along rigidity gradients.

Thème : Thème 2007-2010 : Mécanique cellulaire

Equipe : Physique du vivant (MSC)