P-fimbrial adhesin PapG (PapG)

The Escherichia coli P-fimbriae PapG adhesin is a critical virulence factor located at the distal tip of P-pili in uropathogenic strains of E. coli (UPEC). It functions as a lectin that specifically recognizes and binds to the Gal(alpha1-4)Gal disaccharide core of globoseries glycolipids on the surface of human uroepithelial cells (UniProt: P06779). This binding event is the essential first step for bacterial colonization of the upper urinary tract, allowing the pathogen to resist being washed away by urine flow and leading to acute pyelonephritis (PubMed: 11452310). There are three major molecular variants of PapG (I, II, and III), with PapG-II being the most commonly associated with human kidney infections (PubMed: 7960171). As a primary mediator of infection, PapG is a major target for anti-adhesion therapies, including synthetic carbohydrate analogs and pilicides that inhibit the assembly of the fimbrial structure (PubMed: 16763154). These therapeutic approaches aim to prevent infection by blocking colonization rather than killing the bacteria, which may reduce the selective pressure for antibiotic resistance.

Other names

PapG adhesinP-pilus adhesinGalabiose-binding adhesinGal-Gal pilus adhesinAdhesin PapG

Competitive inhibition of bacterial attachment to host cell glycolipid receptors containing the Gal(alpha1-4)Gal moiety, or disruption of the chaperone-usher pathway required for pilus assembly.