Modelling how curved active proteins and shear flow pattern cellular shape and motility

Area of Science:

• Biophysics
• Cell Biology
• Computational Biology

Background:

• Cell migration and shape are governed by actin cytoskeleton forces.
• Curved membrane complexes coupled to actin polymerization can generate spontaneous membrane patterns.
• Previous models showed this mechanism can lead to cell-like motility on adhesive substrates.

Purpose of the Study:

• To investigate the impact of external shear flow on cell shape and migration.
• To utilize a minimal-cell model to explore cell behavior under flow conditions.
• To compare theoretical predictions with experimental observations.

Main Methods:

• Utilized a "minimal-cell" model incorporating actin cytoskeleton dynamics and membrane-bending active stresses.
• Simulated cell behavior on a uniform adhesive substrate under external shear flow.
• Analyzed cell reorientation, spreading, and migration patterns in response to shear.

Main Results:

• Motile cells in shear flow reorient to face the flow, minimizing adhesion energy and improving spreading.
• Non-motile vesicle shapes primarily slide and roll with the shear flow.
• The model predicts a general mechanism for flow-induced cell behavior.

Conclusions:

• External shear flow significantly influences cell shape and migration dynamics.
• The orientation of motile cells towards flow is an emergent property minimizing adhesion energy.
• The model suggests a universal mechanism for cell responses to flow, potentially explaining cell movement against flow observed in experiments.