FK506-binding protein 12 ligands: a patent review

Introduction: FK506-binding protein 12 (FKBP12) is an endogenous protein with peptidyl-prolyl isomerase (PPIase) activity. Natural compounds FK506, rapamycin and ascomycin, are FKBP12 ligands used for treating organ transplant rejection and other diseases. Small ligands that also interact with FKBP12 are designed and synthetized based on the natural ligands. This suggests that targeting FKBP12 has potential in the treatment of multiple diseases. Areas covered: This article describes the features of FKBP12 and the therapeutic actions of agents targeting FKBP12 reported in the published articles and patents. Expert opinion: The multiple functions of FKBP12 cause side effects during therapy with FKBP12 ligands. The interaction between FKBP12 and other receptors should be explored to guide their use as drugs in the clinical setting. In addition, the neuroprotective mechanism of small-molecule FKBP12 ligands needs further study in order to develop them as novel drugs for treating neurological disorders.