Cofilin

It binds to the sides of ADP-actin in the filament, inducing them to fragment. In this manner cofilin replenishes the pool of free ADPactin which can be recharged by profilin to be used again. Actually dissociation of ADP-actin filaments occurs in two steps - the first requiring cofilin which chops off 18-20mers and a secondary step which requires Aip1 (actininteracting protein 1) which chops the 18-20mers to monomers.