Dominant driver of spontaneous symmetry breaking in 1D cell migration

Determine whether the initiation of spontaneous symmetry breaking leading to polarization and migration of single cells on one-dimensional tracks is dominated by actomyosin-driven processes (enhanced actin polymerization at the leading edge or increased actomyosin contractility at the rear) or by adhesion dynamics (spontaneous adhesion loss at one edge) under experimental conditions.

Background

The paper contrasts two mechanistic routes to spontaneous symmetry breaking (SSB) in cell migration: actomyosin-centric mechanisms (front formation via enhanced actin polymerization or rear retraction via increased contractility) and adhesion-centric mechanisms (spontaneous adhesion failure). Prior active gel models emphasized myosin-driven polarity, while bond-based adhesion models implicated mechanosensitive binding/unbinding dynamics.

Conflicting experimental reports exist: some suggest front-first formation via actin polymerization or rear-first contractility increases, both implicating the actomyosin system, whereas other observations are consistent with adhesion loss triggering rear formation. The authors explicitly state that it is experimentally unclear which process predominates, motivating their coupled active-gel–adhesion model to explore this question.

References

However, in this model adhesion played only a minor role, while in practise, it might play a dominant role for SSB. Experimentally, it is not clear if one process dominates over the other.

— Active gel model for one-dimensional cell migration coupling actin flow and adhesion dynamics  (2405.16870 - Wössner et al., 2024) in Introduction (Section 1)