Arp2/3 Inhibition Induces Amoeboid-Like Protrusions in MCF10A Epithelial Cells by Reduced Cytoskeletal-Membrane Coupling and Focal Adhesion Assembly

Yvonne Beckham (1) , Robert J Vasquez (1) , Jonathan Stricker (2) , Kareem Sayegh (2) , Clément Campillo (3) , Margaret L. Gardel (2) , Cara Gottardi

1 The University of Chicago Medicine [Chicago]
2 University of Chicago
3 LAMBE - Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement

Here we demonstrate that Arp2/3 regulates a transition between mesenchymal and amoeboid protrusions in MCF10A epithelial cells. Using genetic and pharmacological means, we first show Arp2/3 inhibition impairs directed cell migration. Arp2/3 inhibition results in a dramatically impaired cell adhesion, causing deficient cell attachment and spreading to ECM as well as an 8-fold decrease in nascent adhesion assembly at the leading edge. While Arp2/3 does not play a significant role in myosin-dependent adhesion growth, mature focal adhesions undergo large scale movements against the ECM suggesting reduced coupling to the ECM. Cell edge protrusions occur at similar rates when Arp2/3 is inhibited but their morphology is dramatically altered. Persistent lamellipodia are abrogated and we observe a markedly increased incidence of blebbing and unstable pseuodopods. Micropipette-aspiration assays indicate that Arp2/3-inhibited cells have a weak coupling between the cell cortex and the plasma membrane, and suggest a potential mechanism for increased pseudopod and bleb formation. Pseudopods are not sensitive to reduced in formin or myosin II activity. Collectively, these results indicate that Arp2/3 is not necessary for rapid protrusion of the cell edge but plays a crucial role in assembling focal adhesions required for its stabilization.

Domains: Biological Physics [physics.bio-ph]

Yvonne Beckham, Robert J Vasquez, Jonathan Stricker, Kareem Sayegh, Clément Campillo, et al.. Arp2/3 Inhibition Induces Amoeboid-Like Protrusions in MCF10A Epithelial Cells by Reduced Cytoskeletal-Membrane Coupling and Focal Adhesion Assembly. PLoS ONE, 2014, 9 (6), pp.e100943. ⟨10.1371/journal.pone.0100943⟩. ⟨hal-02148251⟩