This family represents a conserved region located towards the N-terminal end of ImpA and related proteins. ImpA is an inner membrane protein, which has been suggested to be involved with proteins that are exported and associated with colony variations in Actinobacillus actinomycetemcomitans [1]. The ImpA gene in Vibrio cholera and many other bacteria is expressed from the virulence factor operon which produces the pathogenic injection, type VI secretion system; although the exact function of this gene-product is not known it appears to be an essential component of the pathogenic effect.

1: impA, a gene coding for an inner membrane protein, influences colonial morphology of Actinobacillus actinomycetemcomitans. Mintz KP, Fives-Taylor PM; Infect Immun 2000;68:6580-6586. PMID:11083768

2: Identification of a conserved bacterial protein secretion system in Vibrio cholerae using the Dictyostelium host model system. Pukatzki S, Ma AT, Sturtevant D, Krastins B, Sarracino D, Nelson WC, Heidelberg JF, Mekalanos JJ; Proc Natl Acad Sci U S A. 2006;103:1528-1533. PMID:16432199