Regensburg 2022 – scientific programme

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BP: Fachverband Biologische Physik

BP 24: Systems Biology, Gene Expression, Signalling

BP 24.1: Invited Talk

Thursday, September 8, 2022, 10:30–11:00, H16

Actin waves as building blocks of cellular function — •Carsten Beta — Institute of Physics and Astronomy, University of Potsdam, Potsdam, Germany

Many cellular functions, such was motility, phagocytosis, and cell division, are driven by coherent patterns of activity in the actin cytoskeleton. Among them, actin waves are a recurrent motive that is commonly observed across different cell types. Here, we present experimental results demonstrating the rich variety of wave patterns in the actin cortex of motile amoeboid cells. We show that ring-shaped actin waves, commonly acting as precursors of macropinocytic cups, can mediate switches between different modes of motility, a pseudopod-based amoeboid mode, and a more persistent, wave-driven migratory mode, reminiscent of keratocyte motility. In multinucleate, oversized amoeboid cells, the same waves may also trigger spontaneous, cell cycle-independent cytofission events, resulting in mononucleated daughter cells of a well-defined size. We also demonstrate that a second wave pattern can coexist with the ring-shaped macropinocytic waves. It emerges in a cell-size dependent manner and consists of rapidly moving planar pulses that show typical signatures of an excitable system. Our experimental findings demonstrate the functional versatility of cortical waves patterns. They can be rationalized based on minimal reaction-diffusion models that mimic the evolution of cortical wave patterns and are coupled to a dynamic phase field to take the cell shape evolution into account. In addition, bifurcation analysis provides a more detailed understanding of how regimes of pattern coexistence may emerge.