Actin network heterogeneity tunes activator-inhibitor dynamics at the cell cortex

Area of Science:

• Cell Biology
• Systems Biology
• Biophysics

Background:

• Biological systems exhibit self-organization via conserved molecular interaction networks.
• Reaction-diffusion equations model emergent dynamics from parameter tuning.
• Integrating these models with heterogeneous biological data is challenging.

Purpose of the Study:

• To develop an activator-inhibitor model for RhoA and F-actin interactions.
• To explain the emergence of diverse RhoA activity patterns (e.g., waves, pulses).
• To investigate the role of actin assembly dynamics and heterogeneity.

Main Methods:

• Developed an activator-inhibitor model incorporating actin assembly and heterogeneity.
• Fitted the model to experimental data summary statistics under parameter constraints.
• Analyzed the combined effects of directional transport and stochasticity in F-actin.

Main Results:

• F-actin assembly dynamics quantitatively tune RhoA activity spatiotemporal patterns.
• A minimal model representation highlights the roles of polymerization and F-actin stochasticity.
• Heterogeneity and anisotropy in F-actin contribute to observed phenotypic diversity.

Conclusions:

• Actin assembly dynamics are key regulators of RhoA activity patterns.
• Phenotypic diversity arises from heterogeneity and anisotropy in cellular components.
• This work advances activator-inhibitor modeling for biological systems.