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Aliases UPK1B, TSPAN20, UPIB, UPK1, uroplakin 1B
External IDs MGI: 98912 HomoloGene: 5065 GeneCards: UPK1B
RNA expression pattern
PBB GE UPK1B 210065 s at fs.png

PBB GE UPK1B 210064 s at fs.png
More reference expression data
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 3: 119.17 – 119.21 Mb Chr 16: 38.77 – 38.8 Mb
PubMed search [1] [2]
View/Edit Human View/Edit Mouse

Uroplakin 1B, also known as UPK1B, is a protein which in humans is encoded by the UPK1B gene.[3][4][5]


The protein encoded by this gene is a member of the transmembrane 4 superfamily, also known as the tetraspanin family. Most of these members are cell-surface proteins that are characterized by the presence of four hydrophobic domains. These proteins mediate signal transduction events that play a role in the regulation of cell development, activation, growth and motility. This encoded protein is found in the asymmetrical unit membrane (AUM) where it can form a complex with other transmembrane 4 superfamily proteins. It may play a role in normal bladder epithelial physiology, possibly in regulating membrane permeability of superficial umbrella cells or in stabilizing the apical membrane through AUM/cytoskeletal interactions. The AUM is believed to be involved in strengthening the cells that line the bladder, and in enhancing the inner bladder membrane's ability to stretch, thus preventing these cells from rupturing during bladder distension. The use of alternate polyadenylation sites has been found for this gene.[3]


  1. ^ "Human PubMed Reference:". 
  2. ^ "Mouse PubMed Reference:". 
  3. ^ a b "Entrez Gene: UPK1B uroplakin 1B". 
  4. ^ Lobban ED, Smith BA, Hall GD, Harnden P, Roberts P, Selby PJ, Trejdosiewicz LK, Southgate J (December 1998). "Uroplakin gene expression by normal and neoplastic human urothelium". Am. J. Pathol. 153 (6): 1957–67. doi:10.1016/S0002-9440(10)65709-4. PMC 1866332Freely accessible. PMID 9846985. 
  5. ^ Finch JL, Miller J, Aspinall JO, Cowled PA (February 1999). "Cloning of the human uroplakin 1B cDNA and analysis of its expression in urothelial-tumor cell lines and bladder-carcinoma tissue". Int. J. Cancer. 80 (4): 533–8. doi:10.1002/(SICI)1097-0215(19990209)80:4<533::AID-IJC9>3.0.CO;2-5. PMID 9935153. 

Further reading[edit]