FAK-mediated spine morphogenesis was shown to occur, in part through Rho guanine nucleotide exchange factor 28 (ARHGEF28, p190RhoGEF), suggesting that FAK-mediated spine maturation might proceed through a FAK-RhoGEF-RHOA mechanism. p190RhoGEF binds directly to phosphorylated PTK2 through a motif in the RhoGEF C-terminal domain, a feature not shared with other GEFs (Moeller et al. 2006, Rico et al. 2004, Zhai et al. 2003).