Dissecting cytoquakes in the actomyosin cortex using super-resolved micropost arrays

The actomyosin network in living cells is an active matter system whose dynamics are responsible for a wide range of cellular behavior. Recent experiments have shown that the cellular cortex exhibits active fluctuations punctuated by rearrangements with large step-like displacements whose size distribution and spatial and temporal correlations resemble those seen in earthquakes and avalanches [1]. We present detailed analysis of the dynamics and size distributions of these cortical "cytoquake" phenomena, via subnanometer particle tracking with poly(dimethylsiloxane) micropost array detectors. We find that, for multiple cell types and substrate stiffnesses, the cortical fluctuations show heavy-tailed distributions whose apparent scaling behavior suggests that a single physical process may account for the dynamics over a wide range of size and time scales.

[1] Y. Shi et al., PNAS 116, 13839 (2019).