Fig. 5
Working model for Srv2/CAP, Cofilin, and Twinfilin functions in actin disassembly. a Srv2 hexamers bind transiently (for ~2 s on average) to the pointed ends of Cofilin-saturated actin filaments. In a subset of these binding events, Srv2 catalyzes the dissociation of actin subunits. Subunits might be released as actin monomers, Cofilin-bound monomers, and/or Cofilin-bound oligomers. b On filaments that are more sparsely decorated with Cofilin, Srv2/CAP can bind to filament sides and enhance Cofilin-mediated severing, in addition to accelerating pointed-end depolymerization of the severing products. Twinfilin interacts with filament barbed ends to promote their depolymerization, where its interactions with Srv2/CAP increase its processivity. The thickness of arrows indicates relative rates of polymerization or depolymerization at the two ends of the filament.
