Uropathogenic Escherichia coli P-fimbrial adhesin PapG (PapG)

Uropathogenic Escherichia coli P-fimbrial adhesin PapG is a critical virulence factor located at the tip of P-fimbriae (pyelonephritis-associated pili). It mediates the specific attachment of uropathogenic E. coli (UPEC) to the galabiose-containing glycolipids (globoseries) found on the surface of host uroepithelial cells, particularly in the kidneys (nih.gov, 1.2.1, 1.2.2). PapG exists in three distinct molecular variants (I, II, and III) that exhibit different receptor binding preferences and clinical associations; for instance, PapG-II is strongly associated with acute pyelonephritis, while PapG-III is more common in cystitis (nih.gov, 1.1.1; oup.com, 1.2.3). By facilitating colonization and preventing bacterial clearance by urine flow, PapG plays a central role in the pathogenesis of upper urinary tract infections. Beyond adhesion, PapG has been shown to protect the bacteria from the bactericidal activity of neutrophils, further enhancing its role in infection persistence (nih.gov, 1.3.4). Therapeutic strategies targeting PapG include the development of anti-adhesion agents, such as galabiose-based glycomimetics, and vaccine candidates designed to elicit neutralizing antibodies that block bacterial anchoring to host tissues (nih.gov, 1.4.1, 2.1.3). These approaches aim to provide alternatives to traditional antibiotics, potentially reducing the selection pressure for antimicrobial resistance. Research into PapG inhibitors has identified potent galabiosides, such as p-methoxyphenyl galabioside, which show promise in preventing UPEC colonization in preclinical models (nih.gov, 1.4.1). Vaccine development efforts have explored recombinant PapG proteins and multi-epitope constructs to provide broad protection against various UPEC strains (jabsonline.org, 2.1.1; nih.gov, 2.1.3).

Other names

PapG-IPapG-IIPapG-IIIP-adhesinF-adhesinGal(alpha1-4)Gal-binding adhesinP-fimbrial tip adhesin

Inhibition of bacterial adhesion to host cell receptors by competitively binding to the galabiose-containing glycolipids (globoseries) on uroepithelial cells.