Encapsulated actomyosin patterns drive cell-like membrane shape changes

Yashar Bashirzadeh; Hossein Moghimianavval; Allen P Liu

doi:10.1016/j.isci.2022.104236

Encapsulated actomyosin patterns drive cell-like membrane shape changes

iScience. 2022 Apr 12;25(5):104236. doi: 10.1016/j.isci.2022.104236. eCollection 2022 May 20.

Authors

Yashar Bashirzadeh¹, Hossein Moghimianavval¹, Allen P Liu^{1

2

3

4}

Affiliations

¹ Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
² Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
³ Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA.
⁴ Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA.

Abstract

Cell shape changes from locomotion to cytokinesis are, to a large extent, driven by myosin-driven remodeling of cortical actin patterns. Passive crosslinkers such as α-actinin and fascin as well as actin nucleator Arp2/3 complex largely determine actin network architecture and, consequently, membrane shape changes. Here we reconstitute actomyosin networks inside cell-sized lipid bilayer vesicles and show that depending on vesicle size and concentrations of α-actinin and fascin actomyosin networks assemble into ring and aster-like patterns. Anchoring actin to the membrane does not change actin network architecture yet exerts forces and deforms the membrane when assembled in the form of a contractile ring. In the presence of α-actinin and fascin, an Arp2/3 complex-mediated actomyosin cortex is shown to assemble a ring-like pattern at the equatorial cortex followed by myosin-driven clustering and consequently blebbing. An active gel theory unifies a model for the observed membrane shape changes induced by the contractile cortex.

Keywords: Biological sciences; Cell biology; Mechanobiology.