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Actin depolymerizing factor (ADF/cofilin) enhances the rate of filament turnover: implication in actin-based motility
M F Carlier1, V Laurent, J Santolini
1Dynamique du Cytosquelette, Laboratoire d'Enzymologie et Biochimie Structurales, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France. carlier@lebs.cnrs-gif.fr
The Journal of Cell Biology
|March 24, 1997
Summary
Actin depolymerizing factor (ADF) enhances actin filament dynamics by increasing monomer dissociation from pointed ends. This mechanism boosts actin-based motility, rather than sequestering actin monomers.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Actin-binding proteins of the actin depolymerizing factor (ADF)/cofilin family regulate actin-based motility.
- ADF1 from Arabidopsis thaliana serves as a model for studying ADF/cofilin family functions.
Purpose of the Study:
- To investigate the function of ADF in regulating actin dynamics.
- To elucidate the mechanism by which ADF influences actin filament turnover and motility.
Main Methods:
- Utilized a combination of physical-chemical methods.
- Employed actin-based motility assays under physiological conditions (pH 7.8).
- Examined ADF binding affinities to different actin-nucleotide states.
Main Results:
- ADF binds ADP-actin with high affinity.
- ADF significantly enhances in vitro actin filament turnover (treadmilling) to in vivo levels.
- ADF accelerates Listeria monocytogenes propulsion by altering actin filament kinetics at pointed ends.
Conclusions:
- ADF's primary function is not G-actin sequestration.
- ADF enhances actin filament dynamics by increasing the rate of actin dissociation from pointed ends.
- ADF utilizes ATP hydrolysis to promote actin-based motile processes.