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Balance between cell−substrate adhesion and myosin contraction determines the frequency of motility initiation in fish keratocytes

2015; National Academy of Sciences; Volume: 112; Issue: 16 Linguagem: Inglês

10.1073/pnas.1417257112

1091-6490

Erin L. Barnhart, Kun-Chun Lee, Greg M. Allen, Julie A. Theriot, Alex Mogilner,

Polymer Surface Interaction Studies

Significance Symmetry breaking and motility initiation are required for many physiological and pathological processes, but the mechanical mechanisms that drive symmetry breaking are not well understood. Fish keratocytes break symmetry spontaneously, in the absence of external cues, with myosin-driven actin flow preceding rear retraction. Here we combine experimental manipulations and mathematical modeling to show that the critical event for symmetry breaking is a flow-dependent, nonlinear switch in adhesion strength. Moreover, our results suggest that mechanical feedback among actin network flow, myosin, and adhesion is sufficient to amplify stochastic fluctuations in actin flow and trigger symmetry breaking. Our mechanical model for symmetry breaking in the relatively simple keratocyte provides a framework for understanding motility initiation in more complex cell types.