Advagraf; FR 900506; Fujimycin; L 679934; Prograf; Protopic; TacroBell; Tacrolimus; Tsukubaenolide; (3S,4R,5S,8R,9E,12S,14S,15R,16S,18R,19R,26aS)-5,6,8,11,12,13,14,15,16,17,18,19,24,25,26,26a-hexadecahydro-5,19-dihydroxy-3-[(1E)-2-[(1R,3R,4R)-4-hydroxy-3-methoxycyclohexyl]-1-methylethenyl]-14,16-dimethoxy-4,10,12,18-tetramethyl-8-(2-propen-1-yl)-15,19-epoxy-3H-pyrido[2,1-c][1,4]oxaazacyclotricosine-1,7,20,21(4H,23H)-tetrone

FK-506 is a potent immunosuppressant and in vitro T cell proliferation blocker. It has been shown to disrupt calcineurin (also known as CaN or phosphatase 2B)-mediated signal transduction in T lymphocytes. The compound interacts with its FK506-binding protein-12 (FKBP12). The resulting complex, in turn, interferes with calcineurin substrate interaction.