UPK1B
Uroplakin 1B: A key component of urothelial differentiation and a biomarker in bladder cancer
Gene Information Card
| Symbol | UPK1B |
|---|---|
| Full Name | uroplakin 1B |
| Gene Type | protein-coding |
| Chromosomal Location | 3q13.32 |
| NCBI Gene ID | 7348 ncbi.nlm.nih.gov/gene/7348 |
| Ensembl ID | ENSG00000114648 |
| UniProt ID | O75841 |
| OMIM ID | 602658 |
| HGNC ID | 12577 |
| Aliases | UPIB, TSPAN20, uroplakin Ib |
Description
UPK1B encodes uroplakin 1B, a member of the tetraspanin family of transmembrane proteins. Uroplakin 1B is a major component of the asymmetric unit membrane (AUM) of urothelial cells, forming heterodimers with uroplakin 3A (UPK3A) and contributing to the permeability barrier of the bladder epithelium. UPK1B is highly expressed in normal urothelium and is frequently downregulated in invasive bladder cancer, making it a potential biomarker for urothelial differentiation and tumor progression.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Bladder cancer (urothelial carcinoma) | Loss of UPK1B expression correlates with epithelial-mesenchymal transition and invasive phenotype; reduced expression is associated with poor prognosis. | ClinVar, COSMIC, NCBI Gene |
| Urothelial carcinoma in situ | Decreased UPK1B expression is observed in high-grade lesions, suggesting a role in early carcinogenesis. | NCBI Gene, PubMed |
| Bladder exstrophy | UPK1B expression may be altered in congenital bladder anomalies, though direct evidence is limited. | OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Bladder | 112.3 | High |
| Urethra | 45.6 | Medium |
| Kidney | 8.2 | Low |
| Prostate | 3.1 | Low |
| Lung | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| RT4 (bladder cancer) | 98.7 | High expression; well-differentiated urothelial cell line |
| T24 (bladder cancer) | 12.4 | Low expression; invasive phenotype |
| 5637 (bladder cancer) | 8.9 | Low expression; poorly differentiated |
| HEK293 (embryonic kidney) | 0.3 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | missense | Rare | Potential loss of start codon; likely loss of function |
| c.124G>A (p.Gly42Arg) | missense | 0.01% (gnomAD) | Unknown significance; may affect protein stability |
| c.347T>C (p.Leu116Pro) | missense | 0.005% (gnomAD) | Unknown significance; located in transmembrane domain |
Mutation functional classification
Loss of Function (LOF)
Loss-of-function mutations in UPK1B are rare but may impair urothelial barrier integrity and contribute to bladder cancer progression.
Gain of Function (GOF)
No gain-of-function mutations have been reported for UPK1B.
Dominant Negative (DN)
No dominant-negative mutations have been described for UPK1B.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Uroplakin complex assembly (Reactome: R-HSA-2168880)
• Keratinization (Reactome: R-HSA-6805567)
• Cell-cell junction organization (Reactome: R-HSA-421270)
Protein Summary
Uroplakin 1B (UPK1B) is a 27 kDa tetraspanin transmembrane protein with four membrane-spanning domains. It forms a heterodimer with uroplakin 3A (UPK3A) and assembles into uroplakin particles that constitute the asymmetric unit membrane (AUM) of urothelial umbrella cells. The AUM provides a rigid, impermeable barrier protecting the bladder from urine toxicity. UPK1B is also involved in cell adhesion, signaling, and cytoskeletal organization. Its expression is highly specific to differentiated urothelium, and loss of UPK1B is a hallmark of invasive bladder cancer.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| UPK1B Knockout HEK293 Cell Line | EDJ-KQ50701 | Human | 7348 | Details Get a Quote |
| UPK1B Knockout HeLa Cell Line | EDJ-KQ54719 | Human | 7348 | Details Get a Quote |
| UPK1B Knockout A-549 Cell Line | EDJ-KQ63210 | Human | 7348 | Details Get a Quote |
| UPK1B Knockout HCT 116 Cell Line | EDJ-KQ71676 | Human | 7348 | Details Get a Quote |
