Mechanisms of Cell Propulsion by Active Stresses

Area of Science:

• Cell biology
• Biophysics
• Mechanobiology

Background:

• Cellular locomotion is crucial for biological processes.
• Cytoskeletal flows and cell-substrate interactions are key drivers of cell motion.
• Understanding these interactions requires sophisticated modeling.

Purpose of the Study:

• To explore the interplay between cytoskeletal flows and cell-substrate interactions.
• To develop a simplified model for predicting cell motion.
• To relate cell speed and traction forces to active stress and friction distributions.

Main Methods:

• A simplified model of the cytoskeleton as a viscous gel with active stresses was employed.
• The model provides explicit general results linking cell mechanics to motion.
• Mathematical analysis was used to derive relationships between model parameters and cell behavior.

Main Results:

• Cell velocity is determined by the asymmetry of active stress distribution.
• Gradients in cell-substrate friction can induce cell motion independently of stress symmetry.
• Traction forces are influenced by the location of protrusive or contractile stresses.
• Cell velocity shows a biphasic dependence on adhesion strength when active stress is adhesion-enhanced.

Conclusions:

• The model successfully explains cell motion based on cytoskeletal properties and substrate interactions.
• Specific, testable predictions for experimental validation were proposed.
• This work provides a framework for understanding the physical basis of cell migration.