drugimmunophilin

Drugimmunophilin is a term used to describe the functional complex formed when an immunophilin protein binds a small-molecule drug. Immunophilins are a family of proteins that bind immunosuppressive drugs and assist in protein folding and isomerization; major subfamilies include FKBP proteins, cyclophilins, and parvulins.

In pharmacology, these drug–immunophilin complexes are the active units that mediate downstream effects. For example, the FKBP12–tacrolimus (FK506) complex inhibits calcineurin phosphatase, blocking NFAT activation and T-cell proliferation. The cyclophilin–cyclosporine A complex also inhibits calcineurin. The FKBP12–rapamycin (sirolimus) complex inhibits the mechanistic target of rapamycin (mTOR), reducing cell growth and proliferation.

Clinical relevance: These interactions underpin organ transplant immunosuppression and treatment of certain autoimmune diseases. They are also explored in oncology and other areas through development of selective immunophilin ligands. Risks include immunosuppression-related infections, nephrotoxicity, and drug interactions.

The term drugimmunophilin is not widely used in standard pharmacology literature; more common is the description of immunophilin–drug complexes or immunophilin-targeted therapies. Ongoing research seeks to improve selectivity, reduce toxicity, and overcome resistance.

See also: immunophilins, calcineurin inhibitors, mTOR inhibitors, tacrolimus, cyclosporine, rapamycin.