Peptidyl-prolyl cis-trans isomerase FKBP2 (FKBP2)

Peptidyl-prolyl cis-trans isomerase FKBP2 (FKBP2) is a member of the immunophilin family of proteins that catalyze the cis-trans isomerization of proline residues in polypeptides, facilitating proper protein folding and trafficking, particularly within the endoplasmic reticulum[1][8][9]. It binds immunosuppressive drugs such as FK506 (tacrolimus) and rapamycin (sirolimus), which inhibit its isomerase activity and can impact immune regulation[1][6][8][9]. FKBP2 primarily functions as an ER chaperone, maintaining protein quality control and ER homeostasis; its dysfunction is associated with connective tissue disorders such as Ehlers-Danlos syndrome, kyphoscoliotic type, and brittle bone disorder[1][2]. The protein is not a receptor, but an enzyme—specifically a rotamase (prolyl isomerase)—that can serve as a pharmacological target for immunosuppressive drugs[5][6][8].

Other names

FKBP13FKBP-2PPIase FKBP213 kDa FK506-binding proteinFK506-binding protein 2Immunophilin FKBP13Rotamase13 kDa FKBPpeptidyl-prolyl cis-trans isomerase FKBP2FKBP-13

Inhibition of prolyl isomerase activity by immunosuppressants (e.g., FK506, rapamycin) through direct binding, modulating immune cell signaling and protein folding