This superfamily contains the N-terminal domain of diaphanous, a subclass of formins whose members are regulated by the binding of a small GTP-binding protein of the Rho subfamily. Drf proteins are characterised by a variety of shared domains: an N-terminal GTPase-binding domain (GBD), formin-homology domains FH1, FH2 (INTERPRO:IPR015425) and FH3 (INTERPRO:IPR010472), and a C-terminal conserved Dia-autoregulatory domain (DAD) that binds the GBD. GBD, the domain represented by the entry, is bound to by GTP-attached Rho proteins, leading to activation of Drfs (Diaphanous-related formins).

GBD is a bifunctional autoinhibitory domain that interacts with and is regulated by activated Rho family members. Mammalian Drf3 contains a CRIB-like motif within its GBD for binding to Cdc42, which is required for Cdc42 to activate and guide Drf3 towards the cell cortex where it remodels the actin skeleton PMID:12676083.

INTERPRO:IPR010473,DOI:10.1074/jbc.M805634200