Salmonella typhimurium employs a type III secretion system to inject bacterial toxins into the host cell cytosol. These toxins transiently activate Rho family GTP-binding protein-dependent signaling cascades to induce cytoskeletal rearrangements. SopE, one of these toxins, can activate Cdc42 in a Dbl-like fashion via its C-terminal GEP domain Pfam:PF07487 [1]. This family represents the N-terminal region of SopE. The function of this domain is unknown.

1: Structural basis for the reversible activation of a Rho protein by the bacterial toxin SopE. Buchwald G, Friebel A, Galan JE, Hardt WD, Wittinghofer A, Scheffzek K; EMBO J 2002;21:3286-3295. PMID:12093730