Regensburg 2019 – wissenschaftliches Programm
BP 27.3: Vortrag
Donnerstag, 4. April 2019, 15:30–15:45, H10
The Poisson ratio of the cellular actin cortex is frequency-dependent — Marcel Mokbel1, Kamran Hosseini2, Sebastian Aland1, and •Elisabeth Fischer-Friedrich2 — 1Hochschule für Technik und Wirtschaft, Dresden, Germany — 2Biotechnology Center, Technische Universität Dresden, Dresden, Germany
Cell shape changes are vital for many physiological processes such as cell proliferation, cell migration and morphogenesis. They emerge from an orchestrated interplay of cellular force generation and cellular force response both crucially influenced by the actin cytoskeleton. To model cellular force response and deformation, cell mechanical models commonly describe the actin cytoskeleton as a contractile isotropic incompressible material. However, in particular at slow frequencies, there is no compelling reason to assume incompressibility as the water content of the cytoskeleton may change. Here we challenge the assumption of incompressibility by comparing computer simulations of an isotropic actin cortex with tunable Poisson ratio to measured cellular force response. Comparing simulation results and experimental data, we determine the Poisson ratio of the cortex in a frequency-dependent manner. Our results show that the Poisson ratio of the cortex depends on the frequency and may deviate from the incompressible case. In addition, our results suggest that the assumption of cortex isotropy is violated at large time scales likely due to anisotropic actin cortex repolymerization from the membrane.