Figure 2.

The structure of the ternary complex between the drug cyclosporin A (CsA), human cyclophilin A (CypA) and human calcineurin [37]. The CsA-CypA binary complex lies at the base of the helical arm of the catalytic subunit of calcineurin (CnA) that binds the regulatory subunit calcineurin (CnB); it nestles in a hydrophobic groove in intimate contact with both subunits, at a region unique to calcineurin and not found in other phosphatases, and this intimate contact gives the interaction high specificity. Reproduced with permission from [37].