uroplakin-1a; UP1a; uroplakin Ia; UPIa; UPKa; tetraspanin-21; Tspan-21 (UPK1A, TSPAN21)

Function

• component of the asymmetric unit membrane (AUM)
• 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 (putative)
• interacts with uroplakin-2 (UPK2) (putative)

Structure

• homodimer; disulfide-linked.
• belongs to the tetraspanin (TM4SF) family

Compartment

membrane

Alternative splicing

named isoforms=2

Expression

• high expression restricted to ureteric urothelium (most superficial cells)
• low expression in prostate expression in normal urothelial cells is lost in culture
• some expression in tumor cell lines derived from urothelial malignancies

More general terms

• transmembrane 4 protein
• uroplakin
• glycoprotein

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=11045
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:11045
• OMIM: https://mirror.omim.org/entry/611557
• UniProt: http://www.uniprot.org/uniprot/O00322.html