Formins participate in the assembly of the actin and microtubule cytoskeletons in processes like cell division, migration, and development. The mammalian Diaphanous-related (mDia) formin family of Rho-effector proteins generates linear actin filaments (F-actin) and modulates microtubule dynamics to support the establishment and maintenance of polarity in cells. These structural changes occur in response to demands during developmental and immunologic processes. Defects in formin genes are associated with an array of human diseases including inherited deafness, autism, and kidney disease[1]. Diaphanous-related formins (DRF) contain an N-terminal GTPase-binding domain (GBD) and a C-terminal diaphanous autoregulatory domain (DAD). DRFs are regulated by an autoinhibitory interaction of the C-terminal DAD with the DRF N-terminal armadillo repeat-like region in the DID or GBD/FH3 domain. This autoinhibition is released upon competitive binding of an activated Rho GTPase to the GBD. The release of DAD allows the catalytical formin homology 2 (FH2) domain to then nucleate and elongate nonbranched actin filaments[2].