Colonization factor antigen I minor subunit E (CfaE)

Colonization factor antigen I minor subunit E (CfaE) is the tip-localized adhesive subunit of the colonization factor antigen I (CFA/I) fimbria, a virulence structure of enterotoxigenic Escherichia coli (ETEC), one of the most common causes of diarrhea in children and travelers[3][6]. CFA/I fimbriae are rigid, rod-like appendages consisting mainly of major subunit CfaB, with a few copies of CfaE at the tip where it is essential for mediating attachment to specific receptors on intestinal epithelial cells and erythrocytes[3][4][6][7][8]. CfaE is assembled via the chaperone-usher pathway and its function is necessary for bacterial colonization of the human small intestine[3][5][6]. Structurally, CfaE contains an N-terminal adhesin domain and a C-terminal pilin domain, with the adhesin domain carrying the receptor-binding activity[6][8]. Mutation studies have shown that specific residues in CfaE are required for receptor binding, highlighting its essential and specific role in pathogenesis[4][6][8]. CfaE has no endogenous human role and is not a human protein; it is a prime candidate for anti-infective strategies aiming to block ETEC colonization by vaccines or neutralizing agents, though no approved drugs currently target CfaE directly[3][6][7].

Other names

CFA/I fimbrial subunit ECfaE adhesinCfaE tip adhesin

Inhibition of host-pathogen adhesion by blocking the CfaE–host receptor interaction; Neutralization of bacterial attachment to the gut epithelium via antibodies or competitive antagonists