Cofilins are ubiquitous, conserved proteins that bind and disassemble actin filaments. When bound to to F-actin, cofilin changes the twist of the actin polymer, promoting the severing and depolymerization of the microfilament. Conversely, in the presence of available ATP-G-actin and the Arp2/3 complex, cofilin may also speed up polymerization by setting up these actin into a more favorable orientation. Thus cofilin serves as an important regulator of microfilament dynamics and cellular structure. Two human genes exist within the cofilin family: CFL1 codes for Cofilin 1 (non-muscle, n-cofilin) and CFL2 codes for Cofilin 2 (muscle, n-cofilin).