Anti-FKBP prolyl isomerase 1B antibodies are used for the immunodetection of the protein encoded by the FKBP1B gene. In humans, the canonical protein has a reported length of 108 amino acid residues and a mass of 11.8 kDa. Its subcellular localization is in the cytoplasm. Alternative splicing is reported to yield 2 different isoforms for this protein. It is notably expressed in the heart muscle. A member of the FKBP-type PPIase protein family, it is known to have the potential to contribute to the immunosuppressive and toxic effects of FK506 and rapamycin. Other names for this target antigen include FKBP1L, OTK4, PKBP1L, PPIase, peptidyl-prolyl cis-trans isomerase FKBP1B, and FKBP12.6. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.