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Micromanipulation Techniques Allowing Analysis of Morphogenetic Dynamics and Turnover of Cytoskeletal Regulators
Published on: May 12, 2018
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Actin Turnover in Lamellipodial Fragments
Dikla Raz-Ben Aroush1, Noa Ofer2, Enas Abu-Shah2
1Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Current Biology : CB
|October 3, 2017
Summary
Actin turnover in lamellipodia involves local network dynamics and global diffusion of actin subunits. This process is crucial for cell motility, with monomers stored in a reserve pool for rapid adaptation.
Area of Science:
- Cell Biology
- Biophysics
- Cytoskeletal Dynamics
Background:
- Actin turnover drives lamellipodial motility, but in vivo dynamics remain unclear.
- Fish epithelial keratocytes offer a simplified model for studying lamellipodia.
Purpose of the Study:
- To characterize the spatiotemporal organization of actin turnover in vivo within lamellipodia.
- To elucidate the mechanisms of actin subunit transport and polymerization.
Main Methods:
- Fluorescence recovery after photobleaching (FRAP)
- Fluorescence correlation spectroscopy (FCS)
- Extraction experiments
Main Results:
- Two-thirds of lamellipodial actin diffuses globally, while one-third forms a treadmilling network.
- Diffusible actin exists as oligomers, indicating severing and debranching in disassembly.
- Monomeric actin is maintained at high concentrations in a non-polymerizable reserve pool.
Conclusions:
- Lamellipodial actin network turnover is local, occurring within seconds.
- Actin subunit transport is global, with diffusion across the entire lamellipodium.
- This dual mechanism ensures robust, adaptable, and regulated actin transport for cell motility.
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