The EPHB2-FAK pathway partially promotes dendritic spine stability through LIMK-mediated cofilin (CFL1) phosphorylation (Shi et al. 2009). CFL1 is a member of the ADF (actin-depolymerizing factor) protein family that is involved in regulating actin dynamics in the growth cone. It binds to actin in a one-to-one molar ratio, and stimulates both the severing of actin filaments and depolymerization of actin subunits from the actin filament end. Activated LIMK phosphorylates CFL1 on the conserved serine 3 residue located near the actin-binding site. After phosphorylation, CFL1 is inactive, loses its affinity for actin and dissociates from G-actin monomers. Once freed, ADP-actin monomers can exchange ADP with cytoplasmic ATP, ready for reincorporation at the barbed end of a growing filament (Gungabissoon & Bamburg 2003).