Dresden 2017 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 55: Cell Migration and Contraction
BP 55.5: Vortrag
Donnerstag, 23. März 2017, 16:30–16:45, HÜL 386
Variability, order and myosin II acceleration of cortical dynamics of motile amoeboid cells — Hsin-Fang Hsu1, Eberhard Bodenschatz1, Alexei Krehkov1, Christian Westendorf1, Azam Gholami1, Alain Pumir2, •Marco Tarantola1, and Carsten Beta3 — 1MPI-DS, Am Fassberg 17, D-37077 Göttingen — 2Laboratoire de Physique, Univ Lyon, ENS, CNRS, F-69342 Lyon — 3Institute of Physics and Astronomy, Univ Potsdam, D-14476 Potsdam
Chemotactic motion of cells relies on membrane protrusions driven by the polymerization and depolymerization of actin. Here we show that the response of the actin system of Dictyostelium discoideum (D.d.) to a receptor stimulus is subject to a threshold value that varies strongly from cell-to-cell. Above threshold, we observe pronounced variability in response amplitudes. Polymerization time, however, is almost constant over the entire range of response amplitudes, while depolymerization time increases with increasing amplitude. We show that cell-to-cell variability in the response amplitude correlates with the amount of Arp2/3, a protein that enhances actin polymerization. Another key player governing dynamics of the actin network is the motor protein myosin II. Upon chemotactic stimulation, myosin II is first released from the cell cortex but then relocates to the cortical region with actin filaments. Using Poincaré mapping, we analyze the detailed dynamical interplay of actin, myosin II and the cell area. Cells lacking myosin II show a deceleration of cortical actin recovery after stimulation, suggesting the important role of myosin II in setting the response time.