FK-506 [Tacrolimus]

Potent immunosuppressant (as cyclosporin A and rapamycin). Suppresses proliferation of cytotoxic T cells and inhibits the production of T cell-derived mediators such as interleukin-2 (IL-2). Forms a complex with FK-506 binding protein 12 (FKBP12). Inhibits the activity of the calcium/calmodulin-dependent protein phosphatase 2B (PP2B; calcineurin), leading to disruption of T cell activation. Prevents rejection of transplanted organs. Anti-inflammatory compound in the treatment of several inflammatory skin diseases (e.g. atopic dermatitis) and with potential anti-rheumatic activity (rheumatoid arthritis). Neuroprotective. Regulates nitric oxide neurotoxicity. Neurotransmitter. Ca2+ release compound. NF-kappaB suppressor by induction of unfolded protein response (UPR). Anti-cancer compound. Apoptosis inducer.