Actin Depolymerizing Factor (ADF/Cofilin) Enhances the Rate of Filament Turnover: Implication in Actin-based Motility

• DOI: 10.1083/jcb.136.6.1307
• Publication Date: 2002-07-26T16:47:50Z
• Authors: Marie-France Carlier; Valérie Laurent; Jérôme Santolini; Ronald Melki; Dominique Didry; Gui-Xian Xia; Yan Hong; Nam-Hai Chua; Dominique Pantaloni
• Keywords: Cofilin; Treadmilling; Actin remodeling; Actin-binding protein; Lamellipodium; MDia1

Actin-binding proteins of the actin depolymerizing factor (ADF)/cofilin family are thought to control actin-based motile processes. ADF1 from Arabidopsis thaliana appears be a good model that is functionally similar other members family. The function ADF in dynamics has been examined using combination physical–chemical methods and motility assays, under physiological ionic conditions at pH 7.8. binds ADPbound forms G- or F-actin with an affinity two orders magnitude higher than ATP- ADP-Pi– bound forms. A major property its ability enhance vitro turnover rate (treadmilling) filaments value comparable observed vivo lamellipodia. increases propulsion Listeria monocytogenes highly diluted, ADF-limited platelet extracts shortens tails. These effects mediated by participation filament assembly, which results change kinetic parameters ends filament. end specific cannot accounted for severing. main relevant effect 25-fold increase dissociation pointed ends, while barbed unchanged. This large rate-limiting step monomer-polymer cycle steady state responsible In conclusion, not sequester G-actin. uses ATP hydrolysis assembly dynamics.