FimH-Uroplakin Ia interface (FimH-UPIa interface)

The FimH-Uroplakin Ia interface is a critical protein-protein and protein-glycan interaction that facilitates the initial attachment of uropathogenic Escherichia coli (UPEC) to the bladder epithelium. This interface is formed when the FimH adhesin, located at the tip of bacterial Type 1 fimbriae, recognizes and binds to mannosylated residues on Uroplakin Ia (UPIa) glycoproteins, which are densely packed on the surface of urothelial umbrella cells (Source: NIH, 2020; ResearchGate, 2026). This binding is essential for bacteria to resist the hydrodynamic forces of micturition and is a prerequisite for subsequent colonization, invasion into host cells, and the formation of intracellular bacterial communities (IBCs) (Source: NIH, 2020). Beyond Type 1 fimbriae, other interfaces such as the PapG-Gal-Gal interaction on P fimbriae mediate adhesion to the kidney epithelium, contributing to pyelonephritis (Source: NIH, 2002). Therapeutic targeting of this interface represents a promising antibiotic-sparing strategy for treating urinary tract infections (UTIs). Small-molecule mannosides, such as GSK3882347, act as competitive antagonists by binding to the FimH lectin domain with high affinity, thereby preventing bacterial attachment to host receptors (Source: ACS, 2024; NIH, 2020). Additionally, vaccines like the FimCH complex and monoclonal antibodies are under development to block these adhesive interactions and provide long-term protection against recurrent UTIs (Source: Science Advances, 2025; BioRxiv, 2024). By specifically inhibiting virulence factors rather than killing bacteria, these anti-adhesion therapies aim to reduce the selective pressure for antimicrobial resistance (Source: NIH, 2020).

Other names

Bacterial adhesion interfaceUPEC-urothelial interfaceType 1 fimbriae-receptor complexPapG-Gal-Gal interfaceFimbriae-mediated protein–protein interfaceFimH-Uroplakin Ia interaction

Competitive inhibition of bacterial adhesins (e.g., FimH) binding to host cell receptors (e.g., Uroplakin Ia) by small-molecule antagonists or antibodies, thereby preventing bacterial colonization and invasion (Source: NIH, 2020; Science Advances, 2025).