Anti-FKBP prolyl isomerase 9 antibodies are used for the immunodetection of the protein encoded by the FKBP9 gene. In humans, the canonical protein has a reported length of 570 amino acid residues and a mass of 63.1 kDa. Its subcellular localization is in the ER. Alternative splicing is reported to yield 3 different isoforms for this protein. It is noted to be involved in protein folding. Post-translational modifications have been described, including phosphorylation and glycosylation. Other names for this target antigen include FKBP63, PPIase, peptidyl-prolyl cis-trans isomerase FKBP9, 63 kDa FK506-binding protein, 63 kDa FKBP, and FKBP60. Gene orthologs have been identified in the mouse, rat, bovine, frog, chimpanzee and chicken species.