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The physics of filopodial protrusion
1Department of Mathematics, Center for Genetics and Development, University of California, Davis, 95616, USA. mogilner@math.ucdavis.edu
Biophysical Journal
|May 10, 2005
Summary
Cellular filopodia, essential for sensing and protrusion, are modeled to reveal mechanics. Optimal length is achieved with ~30 bundled actin filaments, balancing buckling and diffusion for cell migration.
Area of Science:
- Cell Biology
- Biophysics
- Computational Biology
Background:
- Filopodia are dynamic actin-rich protrusions at the cell edge.
- They play critical roles in environmental sensing and cell migration.
- Understanding filopodial mechanics is key to cell motility research.
Purpose of the Study:
- To model the mechanics and spatio-temporal dynamics of filopodia.
- To determine the factors limiting filopodial length and spacing.
- To provide testable predictions for experimental validation.
Main Methods:
- Computational modeling of actin filament bundling and membrane interactions.
- Analysis of filopodial length regulation based on filament number.
- Simulation of filopodia initiation, drift, and merging dynamics.
Main Results:
- Over 10 bundled actin filaments are needed to overcome membrane resistance.
- Filopodial length is limited by buckling (10-30 filaments) or G-actin diffusion (>30 filaments).
- An optimal length of a few microns is achieved with ~30 filaments, with interfilopodial distances governed by initiation, drift, and merging.
Conclusions:
- Filopodial length and spacing are tightly regulated by actin bundling, membrane properties, and diffusion.
- The model predicts specific dependencies of filopodial dynamics on key cellular parameters.
- This work offers insights into the physical basis of cell sensing and migration.