Involved in cytokinesis. Overexpression results in growth inhibition. The DAD domain regulates activation via by an autoinhibitory interaction with the GBD/FH3 domain. This autoinhibition is released upon competitive binding of an activated GTPase. The release of DAD allows the FH2 domain to then nucleate and elongate nonbranched actin filaments (By similarity). Belongs to the formin homology family. BNI1 subfamily. An additional intron is predicted in this sequence to correct a probable sequencing error. An additional intron is predicted in this sequence to correct a probable sequencing error.