Anti-UP1A antibodies enable researchers to detect and measure the UP1A antigen in biological samples. This target is a reported synonym of the UPK1A gene, which encodes uroplakin 1A. This protein is known to function in epithelial cell differentiation, among other biological roles. The human version of UP1A has a canonical amino acid length of 258 residues and a protein mass of 28.9 kilodaltons, although 2 isoforms have been identified. It is reported to be localized in the membrane of cells and notably expressed in the urinary bladder. Other names for this target antigen include TSPAN21 and UPIA.