Anti-GU/RH-II antibodies enable researchers to detect and measure the GU/RH-II antigen in biological samples. This target is a reported synonym of the PIAS1 gene, which encodes protein inhibitor of activated STAT 1. This protein is known to function in fat cell differentiation and the regulation of transcription, among other biological roles. The human version of GU/RH-II has a canonical amino acid length of 651 residues and a protein mass of 71.8 kilodaltons, although 3 isoforms have been identified. It is reported to be localized in the nucleus of cells and widely expressed in many tissue types. Other names for this target antigen include DDXBP1, GBP, and GU/RH-II.