Cytochalasin D acts as an inhibitor of the actin–cofilin interaction

Cofilin, a key regulator of actin filament dynamics, binds to G- and F-actin and promotes actin filament turnover by stimulating depolymerization and severance of actin filaments. In this study, cytochalasin D (CytoD), a widely used inhibitor of actin dynamics, was found to act as an inhibitor of the G-actin–cofilin interaction by binding to G-actin. CytoD also inhibited the binding of cofilin to F-actin and decreased the rate of both actin polymerization and depolymerization in living cells. CytoD altered cellular F-actin organization but did not induce net actin polymerization or depolymerization. These results suggest that CytoD inhibits actin filament dynamics in cells via multiple mechanisms, including the well-known barbed-end capping mechanism and as shown in this study, the inhibition of G- and F-actin binding to cofilin.

► Cytochalasin D inhibits the binding of G- and F-actin to cofilin. ► Cytochalasin D decreases the rates of actin assembly and disassembly in living cells. ► Cytochalasin D does not induce net actin depolymerization and polymerization. ► Cytochalasin D inhibits actin filament dynamics in cells by multiple mechanisms.