Reconstructing actin dynamics of the leading edge from observational data.

Reconstructed actin protrusion dynamics reveal a damped oscillatory cycle dominated by feedback mechanisms in unperturbed cells.

• Why it matters: Understanding natural fluctuations of actin and Arp2/3 complex densities is crucial for revealing the mechanisms of cell migration without perturbation, filling a gap left by traditional perturbative models.
• What they did: Researchers analyzed fluctuations in actin filaments, Arp2/3 complex, and cell edge velocity using phase space and regression analysis to develop linearized and nonlinear models based on observational data from a single experiment.
• The result: The models recover reaction rates and processes in the lamellipodium, indicating that protrusion is driven by a damped oscillatory cycle involving feedback from Arp2/3 and actin density, advancing understanding of natural actin dynamics.