FMNL2 binds activated (GTP-bound) CDC42. FMNL2 can be myristoylated on its N-terminal glycine. Although myristoylation is not necessary for the interaction with CDC42, it contributes to FMNL2 activation. Based on the sequence similarity with mouse formin Dia1, binding of CDC42:GTP relieves the autoinhibition of FMNL2 by displacing the C-terminal autoregulatory DAD domain of FMNL2 from the N-terminal FH3 domain (Rose et al. 2005, Lammers et al. 2005). Since formins function as dimers, it is unclear whether the autoinhibitory interaction between FH3 and DAD domain is intramolecular or intermolecular (Xu et al. 2004, Kuhn and Geyer 2014). FMNL2 can also interact with RAC1 in vitro, but it seems that this interaction is not physiologically relevant (Block et al. 2012).