Uroplakin 1a (UPK1A) (UPK1A)

Uroplakin 1a (UPK1A) is a key integral membrane protein and a member of the tetraspanin family that is highly expressed on the apical surface of the urogenital tract epithelium, particularly in the bladder. It is a primary component of the uroplakin plaques that form the blood-urine barrier, protecting the underlying tissues from toxic substances in the urine. In the context of infectious disease, UPK1A serves as a critical adhesion site for uropathogenic Escherichia coli (UPEC), which utilize the FimH adhesin on their Type 1 pili to bind specifically to the mannose moieties of UPK1A. This adhesion is the initiating step for colonization, invasion, and the formation of intracellular bacterial communities (IBCs) during urinary tract infections (UTIs). Therapeutic interventions targeting these adhesion sites, such as D-mannose and FimH antagonists like sibofimloc, work by competitively inhibiting the bacterial binding to UPK1A, thereby preventing the establishment of infection and reducing recurrence.

Other names

Urogenital Tract Epithelial Adhesion SitesUroplakin-1aUP1aUPK1Urothelial Adhesion ReceptorMannose-binding siteMannosylated glycoproteins

Competitive inhibition of bacterial adhesin (e.g., FimH) binding to host mannose receptors on the urogenital epithelium, preventing bacterial colonization and invasion.