~7 nm
- Allows cells to move by lamellipodia ~3 µm/min
- ADP-actin dissociates at the pointed end (i.e. negative end), gets phosphorylated (sped up by profilin) to ATP-actin, and adds to the barbed end (positive end)
- Cofilin may break up the microfilaments to increase the number of open ends of microfilaments
