Phosphorylation of cofilin by LIMK-1

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).

EPHB2-FAK通路通过LIMK介导的Cofilin（CFL1）磷酸化（Shi等人，2009年）部分促进树突棘的稳定性。CFL1是ADF（肌动蛋白解聚因子）蛋白家族的成员，该家族参与调节生长锥中的肌动蛋白动态。它以一比一摩尔的比例与肌动蛋白结合，并刺激肌动蛋白丝的断裂以及从肌动蛋白丝末端解聚肌动蛋白亚基。激活的LIMK在靠近肌动蛋白结合位点的保守丝氨酸3残基上磷酸化CFL1。磷酸化后，CFL1失活，丧失对肌动蛋白的亲和力并从G-肌动蛋白单体上解离。一旦释放，ADP-肌动蛋白单体可以与细胞质中的ATP交换ADP，为在生长丝的尖端重新结合做好准备（Gungabissoon和Bamburg，2003年）。