Focal adhesion kinase 1 (PTK2, FAK, FAK1) acts downstream of EPHB receptors in hippocampal neurons and the EPHB2-FAK signaling contributes to the dendritic spine morphogenesis and synapse maturation by suppressing the activity of actin severing cofilin through phosphorylation. Activation of EPHBs by ephrin-B (EFNB) stimulates the binding of FAK to EPHB. Knock out of FAK in mature neurons induces a shift of mushroom shaped mature dendritic spines to long filopodia like structures, suggesting that synapse formation or maturation is affected in FAK-/- neurons (Shi et al. 2009, Moeller et al. 2006).