Dresden 2017 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 25: Posters - Cytoskeletal Filaments
BP 25.8: Poster
Dienstag, 21. März 2017, 14:00–16:00, P2-EG
Dynamics of circular dorsal ruffles and their role in cancer — Erik Bernitt1,2,3, Julia Lange1, •Malte Ohmstede1, Nir Gov2, Arik Yochelis3, and Hans-Günther Döbereiner1 — 1Institut für Biophysik, Universität Bremen — 2Department of Chemical Physics, Weizmann Institute of Science, Israel — 3Department of Solar Energy and Environmental Physics, Ben-Gurion University of the Negev, Israel
Cells utilize the actin cytoskeleton to actively remodel their morphologies. This enables them to internalize extracellular fluid and activated membrane receptors via macropinocytosis. To form large vesicles this endocytotic mechanism relies on the contraction and closure of actin-based, ring-shaped vertical protrusions at the dorsal cell membrane that are known as Circular Dorsal Ruffles (CDRs). CDRs are essential to a range of vital and pathogenic processes alike. We show that CDRs are propagating fronts of actin polymerization in a bistable system. A new model assigns the expansion and contraction of waves to distinct counter-propagating fronts of different velocities. Under a change in biochemical conditions, CDRs may be pinned and fluctuate near the cell boundary or result in complex spiral wave dynamics due to a wave instability. Indeed, both phenomena are found in our data [1] pointing at the conditions for which macropinocytosis is suppressed. The latter scenario is valid for, e.g., confined CDRs on quasi one-dimensional tracks. We investigate the stochastic dynamics of these states as a function of biochemical conditions and find evidence of stochastic resonance. [1] E.Bernitt, C.G.Koh, N.Gov, HG Döbereiner, PLOS One 10 (1), e0115857 (2015)