Stress fibres are embedded in a contractile cortical network.

Nature materials (2020-10-21)
Timothée Vignaud, Calina Copos, Christophe Leterrier, Mauricio Toro-Nahuelpan, Qingzong Tseng, Julia Mahamid, Laurent Blanchoin, Alex Mogilner, Manuel Théry, Laetitia Kurzawa
ABSTRACT

Contractile actomyosin networks are responsible for the production of intracellular forces. There is increasing evidence that bundles of actin filaments form interconnected and interconvertible structures with the rest of the network. In this study, we explored the mechanical impact of these interconnections on the production and distribution of traction forces throughout the cell. By using a combination of hydrogel micropatterning, traction force microscopy and laser photoablation, we measured the relaxation of traction forces in response to local photoablations. Our experimental results and modelling of the mechanical response of the network revealed that bundles were fully embedded along their entire length in a continuous and contractile network of cortical filaments. Moreover, the propagation of the contraction of these bundles throughout the entire cell was dependent on this embedding. In addition, these bundles appeared to originate from the alignment and coalescence of thin and unattached cortical actin filaments from the surrounding mesh.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Fibronectin bovine plasma, solution, sterile-filtered, BioReagent, suitable for cell culture
Sigma-Aldrich
Phalloidin, Fluorescein Isothiocyanate Labeled, peptide from Amanita phalloides
Sigma-Aldrich
3-(Trimethoxysilyl)propyl methacrylate, ≥97%
Sigma-Aldrich
CK-869, ≥98% (HPLC)
Sigma-Aldrich
Anti-α-Actinin Antibody, clone AT6/172, clone AT6/172, Upstate®, from mouse