A microtubule-based minimal model for spontaneous and persistent spherical cell polarity

Area of Science:

• Cell Biology
• Biophysics
• Systems Biology

Background:

• Cellular polarity is fundamental for cell function and development.
• Understanding the minimal requirements for polarity generation is crucial for synthetic biology.
• Existing models often lack dynamic components or simple feedback mechanisms.

Purpose of the Study:

• To propose and analyze a minimal biophysical model for spontaneous cell polarity.
• To investigate the role of dynamic microtubules and a mobile polarity factor in establishing asymmetry.
• To explore the potential for biochemical reconstitution of cell polarity.

Main Methods:

• Analytical modeling of a spherical cell with a central centrosome.
• Incorporation of a mobile polarity factor binding to dynamic microtubules.
• Feedback mechanism: increased microtubule residence time with polarity factor density.
• Validation using 2D particle-based simulations.

Main Results:

• The model analytically predicts a stable, unipolar, symmetry-broken state.
• This state is robust across a wide range of model parameters.
• Simulations confirm the analytical predictions, demonstrating emergent polarity.
• The system effectively generates persistent cell asymmetry.

Conclusions:

• A minimal set of components (dynamic microtubules, polarity factor, feedback) can generate cell polarity.
• The proposed model offers a framework for understanding polarity in simplified cellular environments.
• This work paves the way for bottom-up construction of polarized cells via biochemical reconstitution.