TY  - INPR
U1  - Preprint
A1  - Cordes, Andrea
A1  - Witt, Hannes
A1  - Gallemí-Pérez, Aina
A1  - Brückner, Bastian
A1  - Grimm, Florian
A1  - Vache, Marian
A1  - Oswald, Tabea
A1  - Bodenschatz, Jonathan
A1  - Flormann, Daniel A.
A1  - Lautenschläger, Franziska
A1  - Tarantola, Marco
A1  - Janshoff, Andreas
T1  - Pre-stress of actin cortices is important for the viscoelastic response of living cells
T2  - bioRxiv
N2  - 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 obtaintime-dependent rheological responses of fibroblasts and MDCK II cells from deformation-relaxationcurves using an atomic force microscope to access the dependence of cortex fluidity on pre-stress. We introduce a viscoelastic model that treats the cell as a composite shell and assumes thatrelaxation of the cortex follows a power law giving access to cortical pre-stress, area compressibilitymodulus, and the power law (fluidity)  exponent. Cortex fluidity is modulated by interferingwith  myosin activity. We find that the power law exponent of the  cell cortex decreases withincreasing intrinsic pre-stress  and  area compressibility modulus, in accordance with  previousfinding for isolated actin networks subject to external stress. Extrapolation to zero tension returnsthe theoretically  predicted power law exponent for transiently cross-linked  polymer networks. In contrast to the widely used Hertzian  mechanics, our model provides viscoelastic  parametersindependent of indenter geometry and compression velocity.
Y1  - 2020
UN  - https://nbn-resolving.org/urn:nbn:de:bsz:291:415-23
U6  - https://doi.org/10.1101/783613
DO  - https://doi.org/10.1101/783613
SP  - 4
S1  - 4
PB  - bioRxiv
ER  -