P-fimbrial tip adhesin PapG (PapG)

PapG is the tip-located adhesin protein of P fimbriae (pili) found on uropathogenic Escherichia coli (UPEC). It plays a critical role in the pathogenesis of upper urinary tract infections by mediating the specific attachment of bacteria to the Gal(alpha1-4)Gal moiety of glycosphingolipids, such as the P blood group antigens, on human renal epithelial cells (PMID: 11053306, PMID: 15138251). There are three major molecular variants of PapG (I, II, and III), each with distinct receptor specificities that influence the tissue tropism and severity of the infection, with PapG II being most strongly associated with acute pyelonephritis (PMID: 10417315). As a therapeutic target, PapG is the focus of anti-adhesion strategies where synthetic galabiose-based glycoconjugates or small molecule inhibitors are used to competitively block bacterial docking, thereby preventing colonization and facilitating the mechanical clearance of the pathogen from the urinary tract (PMID: 22435347, PMID: 28810340). This approach offers a potential alternative or adjunct to traditional antibiotics, particularly in the context of rising antimicrobial resistance.

Other names

PapG adhesinP-fimbriae pilus tip adhesinGal-Gal binding adhesinUropathogenic E. coli adhesin PapG

Competitive inhibition of bacterial attachment to host cell glycolipid receptors (Gal-alpha1-4Gal) to prevent colonization and infection.