UPKs
The uroplakins (UPs) are a family of proteins which associate with each other and form plaques on the apical surface of the urothelium.
These plaques contribute to a permeability barrier, preventing the influx of urine from the urinary tract lumen.
The asymmetric unit membrane (AUM) of mammalian bladder epithelium is believed to be involved in strengthening and stabilizing the urothelial apical surface, thus preventing the cells from rupturing during bladder distention. The major protein components of AUM are uroplakins (UPKs): UPK1A, UPK1B, UPK2, and UPK3.
Pathology
UPK3 mutations in renal adysplasia (#15888565#)
References
Jenkins D, Woolf AS. Uroplakins: new molecular players in the biology of urinary tract malformations. Kidney Int. 2007 Feb;71(3):195-200. PMID: #17183244#