Dresden 2026 – scientific programme
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BP: Fachverband Biologische Physik
BP 12: Cytoskeleton I
BP 12.7: Talk
Tuesday, March 10, 2026, 11:30–11:45, BAR/0205
Coexistence and selection of branched actin networks — •Valentin Wössner1,2, Falko Ziebert1,2, and Ulrich S. Schwarz1,2 — 1Institute for Theoretical Physics, Heidelberg University, Philosophenweg 19, 69120 Heidelberg, Germany — 2BioQuant, Heidelberg University, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
The actin cytoskeleton is crucial for essential cellular processes such as division, migration, and shape regulation. Most cellular actin structures are continuously turned over while keeping similar sizes. However, they are coupled through a shared and finite pool of actin monomers, which begs the question of how they can control their sizes. For branched actin networks, we suggest that local depletion of actin monomers at the leading edge constitutes a generic negative feedback mechanism between the current state of a structure (filament density) and its growth rate (creation of new branches). We derive a single equation capturing this local feedback and the global competition between different networks. Our theory leads to well-defined steady states even in the case of multiple networks sharing the same pool of monomers, without any need for specific molecular processes, in agreement with recent experiments on reconstituted systems. We also present the phase diagram for the transition from coexistence to selection under increased competition.
Keywords: Limited pools; Branched actin networks; Dynamical systems