calcineurin phosphatase

Cyclosporin A is a natural product and an active fungal metabolite, classified as a cyclic polypeptide immunosuppressant. It binds to cyclophilin and inhibits the activity of calcineurin (IC₅₀ = 7 nM) as well as CD11a/CD18 adhesion molecules. It is commonly used to induce uremia models.

Tacrolimus (FK506, Fujimycin) is a macrolide immunosuppressant that binds to FKBP12 to form a high-affinity complex (Ki = 0.2 nM), which inhibits calcineurin phosphatase activity, thereby suppressing T lymphocyte signal transduction and the transcription and release of IL-2. It exerts potent immunosuppressive effects and can be used to induce immunosuppression models.