Anti-XBP1 antibodies are used in the immunodetection of the protein X-box binding protein 1. In humans, the canonical protein has a reported length of 261 amino acid residues and a mass of 28.7 kDa. Its subcellular localization is in the ER. Up to 2 different isoforms have been reported for this protein. It is reported to be expressed in plasma cells in rheumatoid synovium. A member of the BZIP protein family, XBP1 is known to function as a transcription factor during endoplasmic reticulum (ER) stress by regulating the unfolded protein response (UPR). Post-translational modifications have been described, including ubiquitination, acetylation and protein cleavage. The XBP1 marker can be used to identify Plasma Cells and Plasmablasts.* Synonyms for this target antigen include TREB5, XBP2, tax-responsive element-binding protein 5, and TREB-5. XBP1 gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.
*HuBMAP Human Reference Atlas v1.4