This family consists of several EspG like proteins from Citrobacter rodentium and Escherichia coli. EspG is secreted by the type III secretory system and is translocated into host epithelial cells. EspG is homologous with Shigella flexneri protein VirA and can rescue invasion in a Shigella virA mutant, indicating that these proteins are functionally equivalent in Shigella. EspG plays an accessory but as yet undefined role in EPEC virulence that may involve intestinal colonisation [1].

1: EspG, a novel type III system-secreted protein from enteropathogenic Escherichia coli with similarities to VirA of Shigella flexneri. Elliott SJ, Krejany EO, Mellies JL, Robins-Browne RM, Sasakawa C, Kaper JB; Infect Immun 2001;69:4027-4033. PMID:11349072