Uroplakin 3B (UPK3B)

UPK3B is a minor component of the apical plaques of mammalian urothelium that binds and dimerizes with uroplakin-1b (UPK1B), one of the major conserved urothelium membrane proteins.Mouse and bovine Upk3b, which both share over 90% amino acid identity with UPK3B. Bovine Upk3b contains a signal peptide, a transmembrane domain, an N-terminal extracellular domain containing several N-glycosylation sites, and a short C-terminal cytoplasmic domain. The N-terminal extracellular domain contains an 80-amino acid sequence with homology to PMS2L11. Northern blot, Western blot, and immunohistochemical studies detected urothelium-specific expression of Upk3b mRNA and protein in bovine and mouse tissues.