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In Vitro Reconstitution of Self-Organizing Protein Patterns on Supported Lipid Bilayers
Published on: July 28, 2018
Wave-pinning and cell polarity from a bistable reaction-diffusion system.
Yoichiro Mori1, Alexandra Jilkine, Leah Edelstein-Keshet
1Institute of Applied Mathematics and Department of Mathematics University of British Columbia, Vancouver, Canada.
Biophysical Journal
|January 24, 2008
Summary
Eukaryotic cell polarization is explained by a minimal biochemical system. This "wave-pinning" mechanism uses a single protein pair with positive feedback to achieve stable cell polarity, distinct from Turing instabilities.
Area of Science:
- Cell biology
- Biophysics
- Systems biology
Background:
- Motile eukaryotic cells exhibit polarization in response to external signals.
- Proteins like PI3K, PTEN, and Rho GTPases (Cdc42, Rac, Rho) are crucial for symmetry breaking and polarization.
- These proteins cycle between active membrane-bound and inactive cytosolic states.
Purpose of the Study:
- To investigate a simpler biochemical system for cell polarization.
- To demonstrate that a single active/inactive protein pair with positive feedback can achieve inherent polarizability.
- To elucidate the mechanism of this minimal system using mathematical analysis.
Main Methods:
- Mathematical analysis of reaction-diffusion systems.
- Modeling of a minimal system with a single active/inactive protein pair and positive feedback.
- Comparison with Turing-instability-generated pattern formation.
Main Results:
- A minimal system with a single protein pair and positive feedback exhibits inherent polarizability.
- The phenomenon, termed "wave-pinning," relies on unequal diffusion rates of active/inactive forms and conservation.
- Wave-pinning is distinct from Turing-instability patterns and explains spatial amplification, polarity maintenance, and sensitivity to stimuli.
Conclusions:
- A simple biochemical circuit with wave-pinning dynamics can explain eukaryotic cell polarization.
- This mechanism accounts for key features of cell polarization, including spatial amplification and responsiveness.
- The findings offer a new perspective on the fundamental mechanisms of cell polarity.
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