This family includes IpaB, which is an invasion plasmid antigen from Shigella [1], as well as EvcA from E. coli Swiss:Q9ZNF1. Members of this family seem to be involved in pathogenicity of some enterobacteria. However the exact function of this component is not clear.

1: Bacterial signals and cell responses during Shigella entry into epithelial cells. Tran Van Nhieu G, Bourdet-Sicard R, Dumenil G, Blocker A, Sansonetti PJ; Cell Microbiol 2000;2:187-193. PMID:11207575

2: Translocated intimin receptors (Tir) of Shiga-toxigenic Escherichia coli isolates belonging to serogroups O26, O111, and O157 react with sera from patients with hemolytic-uremic syndrome and exhibit marked sequence heterogeneity. Paton AW, Manning PA, Woodrow MC, Paton JC; Infect Immun 1998;66:5580-5586. PMID:9784578