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Journal Articles Biophysical Journal Year : 2010

Force Generation of Curved Actin Gels Characterized by Combined AFM-Epifluorescence Measurements

Abstract

Polymerization of actin into branched filaments is the driving force behind active migration of eukaryotic cells and motility of intracellular organelles. The site-directed assembly of a polarized branched array forms an expanding gel that generates the force that pushes the membrane. Here, we use atomic force microscopy to understand the relation between actin poly-merization and the produced force. Functionalized spherical colloidal probes of varying size and curvature are attached to the atomic force microscopy cantilever and initiate the formation of a polarized actin gel in a solution mimicking the in vivo context. The gel growth is recorded by epifluorescence microscopy both against the cantilever and in the perpendicular (lateral) noncon-strained direction. In this configuration, the gel growth stops simultaneously in both directions at the stall force, which corresponds to a pressure of 0.15 nN/µm2. The results show that the growth of the gel is limited laterally, in the absence of external force, by internal mechanical stresses resulting from a combination of the curved geometry and the molecular mechanism of site-directed assembly of a cohesive branched filament array.

Dates and versions

hal-01960894 , version 1 (11-01-2019)

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Stephan Schmidt, Emmanuèle Helfer, Marie-France Carlier, Andreas Fery. Force Generation of Curved Actin Gels Characterized by Combined AFM-Epifluorescence Measurements. Biophysical Journal, 2010, 98 (10), pp.2246-2253. ⟨10.1016/j.bpj.2010.01.055⟩. ⟨hal-01960894⟩
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