Mechanical interplay between cell shape and actin cytoskeleton organization

Soft Matter, vol. 16, pp. 6328–6343

Abstract

We investigate the mechanical interplay between the spatial organization of the actin cytoskeleton and the shape of animal cells adhering on micropillar arrays. Using a combination of analytical work, computer simulations and in vitro experiments, we demonstrate that the orientation of the stress fibers strongly influences the geometry of the cell edge. In the presence of a uniformly aligned cytoskeleton, the cell edge can be well approximated by elliptical arcs, whose eccentricity reflects the degree of anisotropy of the cell's internal stresses. Upon modeling the actin cytoskeleton as a nematic liquid crystal, we further show that the geometry of the cell edge feeds back on the organization of the stress fibers by altering the length scale at which these are confined. This feedback mechanism is controlled by a dimensionless number, the anchoring number, representing the relative weight of surface-anchoring and bulk-aligning torques. Our model allows to predict both cellular shape and the internal structure of the actin cytoskeleton and is in good quantitative agreement with experiments on fibroblastoid (GDβ1, GDβ3) and epithelioid (GEβ1, GEβ3) cells.

Authors 6

1. Koen Schakenraad Aachen Mathematical Institute

   Leiden University

   Affiliation as printed

   2300 RA Leiden

   Instituut-Lorentz

   Leiden University

   Mathematical Institute

   The Netherlands

   Mathematical Institute, Leiden University, P.O. Box 9512, 2300 RA Leiden, The Netherlands

2. Wim Pomp Aachen Kamerlingh Onnes-Huygens Laboratory

   Leiden University · The Netherlands Cancer Institute

   Affiliation as printed

   2300 RA Leiden

   Division of Gene Regulation

   Kamerlingh Onnes-Huygens Laboratory

   Leiden University

   The Netherlands

   Division of Gene Regulation, The Netherlands Cancer Institute, P.O. Box 90203, 1006 BE Amsterdam, The Netherlands

   Kamerlingh Onnes-Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands

3. Erik H.J. Danen Aachen Leiden Academic Centre for Drug Research

   Leiden University

   Affiliation as printed

   2300 RA Leiden

   Leiden Academic Center for Drug Research

   Leiden University

   The Netherlands

   Leiden Academic Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands

4. Roeland M. H. Merks Aachen Mathematical Institute

   Leiden University

   Affiliation as printed

   2300 RA Leiden

   Institute of Biology

   Leiden University

   Mathematical Institute

   The Netherlands

   Mathematical Institute, Leiden University, P.O. Box 9512, 2300 RA Leiden, The Netherlands

5. Thomas Schmidt Aachen Kamerlingh Onnes-Huygens Laboratory

   Leiden University

   Affiliation as printed

   2300 RA Leiden

   Kamerlingh Onnes-Huygens Laboratory

   Leiden University

   The Netherlands

   Kamerlingh Onnes-Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands

6. Luca Giomi corresponding Aachen Instituut-Lorentz

   Leiden University

   Affiliation as printed

   2300 RA Leiden

   Instituut-Lorentz

   Leiden University

   The Netherlands

   Instituut Lorentz, Leiden University, P.O. Box 9506, 2300 RA Leiden, The Netherlands