SH3 (Src homology 3) domains are often indicative of a protein involved in signal transduction related to cytoskeletal organisation. First described in the Src cytoplasmic tyrosine kinase Swiss:P12931. The structure is a partly opened beta barrel.
Guanine nucleotide exchange factor for Rho/Rac/Cdc42-like GTPases Also called Dbl-homologous (DH) domain. It appears that Pfam:PF00169 domains invariably occur C-terminal to RhoGEF/DH domains.