<p>Formin homology (FH) proteins play a crucial role in the reorganisation of the actin cytoskeleton, which mediates various functions of the cell cortex including motility, adhesion, and cytokinesis [<cite idref="PUB00014909"/>]. Formins are multidomain proteins that interact with diverse signalling molecules and cytoskeletal proteins, although some formins have been assigned functions within the nucleus. Formins are characterised by the presence of three FH domains (FH1, FH2 and FH3), although members of the formin family do not necessarily contain all three domains [<cite idref="PUB00014910"/>]. The proline-rich FH1 domain mediates interactions with a variety of proteins, including the actin-binding protein profilin, SH3 (Src homology 3) domain proteins, and WW domain proteins. The FH2 domain (<db_xref db="INTERPRO" dbkey="IPR003104"/>) is required to inhibit actin polymerisation. The FH3 domain is less well conserved and is required for directing formins to the correct intracellular location, such the mitotic spindle [<cite idref="PUB00014915"/>], or the projection tip during conjugation [<cite idref="PUB00014914"/>]. In addition, some formins can contain a GTPase-binding domain (GBD) (<db_xref db="INTERPRO" dbkey="IPR010473"/>) required for binding to Rho small GTPases, and a C-terminal conserved Dia-autoregulatory domain (DAD).</p><p>This entry represents the FH3 domain.</p>