Uroplakin-3a is a protein that in humans is encoded by the UPK3A gene.

This gene encodes a member of the uroplakin family, a group of transmembrane proteins that form complexes on the apical surface of the bladder epithelium. Mutations in this gene may be associated with renal adysplasia. Alternatively spliced transcript variants have been described.
Function: Component of the asymmetric unit membrane (AUM); a highly specialized biomembrane elaborated by terminally differentiated urothelial cells. May play an important role in AUM-cytoskeleton interaction in terminally differentiated urothelial cells. It also contributes to the formation of urothelial glycocalyx which may play an important role in preventing bacterial adherence (By similarity).