Mathematical Modeling of Myosin Induced Bistability of Lamellipodial Fragments

TL;DR

This paper extends a mathematical model of lamellipodia to include actin-myosin interactions, demonstrating bistability that aligns with experimental observations through simulations and simplified analysis.

Contribution

The work introduces a new description of actin-myosin interaction into the FBLM, revealing bistable cytoskeleton dynamics consistent with experimental data.

Findings

Model exhibits bistability with stable states matching experiments

Numerical simulations confirm the model's behavior

Simplified analysis supports the full model's results

Abstract

For various cell types and for lamellipodial fragments on flat surfaces, externally induced and spontaneous transitions between symmetric nonmoving states and polarized migration have been observed. This behavior is indicative of bistability of the cytoskeleton dynamics. In this work, the Filament Based Lamellipodium Model (FBLM), a two-dimensional, anisotropic, two-phase continuum model for the dynamics of the actin filament network in lamellipodia, is extended by a new description of actin-myosin interaction. For appropriately chosen parameter values, the resulting model has bistable dynamics with stable states showing the qualitative features observed in experiments. This is demonstrated by numerical simulations and by an analysis of a strongly simplified version of the FBLM with rigid filaments and planar lamellipodia at the cell front and rear.