Prestress and Area Compressibility of Actin Cortices Determine the Viscoelastic Response of Living Cells

• DOI: 10.1103/physrevlett.125.068101
• Publication Date: 2020-08-07T01:13:11Z
• Authors: Andrea Cordes; Hannes Witt; Aina Gallemí-Pérez; Bastian Brückner; Florian Grimm; Marian Vache; Tabea Oswald; Jonathan Bodenschatz; Daniel Flormann; Franziska Lautens...; Marco Tarantola; Andreas Janshoff
• Keywords: 0301 basic medicine; Compressive Strength; Viscosity; Cell Membrane; Fibroblasts; Myosins; Microscopy, Atomic Force; Models, Biological; Actins; Elasticity; Biomechanical Phenomena; Cell Line; 03 medical and health sciences; Dogs; Animals; Rheology

Shape, dynamics, and viscoelastic properties of eukaryotic cells are primarily governed by a thin, reversibly cross-linked actomyosin cortex located directly beneath the plasma membrane. We obtain time-dependent rheological responses fibroblasts MDCK II from deformation-relaxation curves using an atomic force microscope to access dependence fluidity on prestress. introduce model that treats cell as composite shell assumes relaxation follows power law giving cortical prestress, area-compressibility modulus, exponent (fluidity). Cortex is modulated interfering with myosin activity. find decreases increasing intrinsic prestress in accordance previous finding for isolated actin networks subject external stress. Extrapolation zero tension returns theoretically predicted transiently polymer networks. In contrast widely used Hertzian mechanics, our provides parameters independent indenter geometry compression velocity.