May play a role in the control of cell motility and survival of macrophages (By similarity). Plays a role in the regulation of cell morphology and cytoskeletal organization. Required in the cortical actin filament dynamics and cell shape. Interacts with RAC1, PFN1 and PFN2 (By similarity). Interacts (activated by RAC1) with SRGAP2 (via SH3 domain); regulates the actin filament severing activity of FMNL1. Recruited to actin-rich phagosomes during phagocytosis. Translocates to the plasma membrane upon activation by RAC1 (By similarity). Colocalized with F-actin in bleb protrusions. Expressed in heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas. The DAD domain regulates activation via by an autoinhibitory interaction with the N-terminus. 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). Myristoylation mediates membrane localization and blebbing. Due to intron retention. Constitutively activated form, probably due to alterations in the DAD domain. Belongs to the formin homology family.