Figure 2 Structure of calcineurin in complex with CsA/Cyp18 and FK506/FKBP12. The structure of the human calcineurin a isoform is shown in com- plex with (A) CsA/Cyp18 (PDB entry 1MF8) and (B) FK506/ FKBP12 (PDB entry 1TCO). The C-terminal truncated catalytic subunit is indicated in blue and the regulatory subunit in brown. CsA (each amino acid individually colored as ball and stick) was complexed with human cyclophilin 18 (yellow) and FK506 (also as ball and stick) was shown in complex with human FKBP12 (green).