Plays a role in the formation of adherens junction and the polymerization of linear actin cables. Interacts with alpha-catenin and may interact with tubulin. Localization to the adherens junctions is alpha-catenin-dependent. Also localizes to F-actin bundles originating from adherens junctions. Isoform 2 localizes to microtubules. Additional isoforms seem to exist. It is present in the adult kidney, testis, limb, ovary, brain, small intestine, salivary gland and harderian gland. Isoforms 1, 2 and 5 are detected in skin and keratinocytes. Isoform 5 is found throughout the embryo. It is present throughout the embryo. In the developing limb bud, the protein is expressed in the apical ectodermal ridge and the mesenchymal compartment, predominantly in the posterior region. During kidney morphogenesis, expression is initially restricted to the epithelial compartment of the pronephros and mesonephros. Isoform 5 is found in the apical ectodermal ridge and the mesenchymal compartment of the developing limb bud. Phosphorylated on serine and possibly threonine residues. Was originally thought to play a role in limb bud development based on the fact that limb deformity (ld) mutants are associated with Fmn1 gene disruption. However, PubMed:15198975 shows that limb deformity mutations rather affects Grem1 cis-regulatory regions localized in Fmn1 gene and that loss of Grem1 (gremlin-1) expression is the cause of limb malformations. Belongs to the formin homology family. Cappuccino subfamily.