Crystal Structure of Human Calcineurin Complexed with Cyclosporin a and Human CyclophilinJin, L., Harrison, S.C.
(2002) Proc Natl Acad Sci U S A 99: 13522
- PubMed: 12357034
- DOI: https://doi.org/10.1073/pnas.212504399
- Primary Citation of Related Structures:
- PubMed Abstract:
Calcineurin (Cn), a Ca(2+)/calmodulin-dependent Ser/Thr protein phosphatase, is an important participant in signaling pathways that activate T cells. It is the target of the immunosuppressive drugs cyclosporin A (CsA) and FK506. These drugs bind proteins known as cyclophilin (Cyp) and FK506-binding protein, respectively, and the drug-protein complexes in turn inhibit Cn. We report the crystal structure of a Cyp/CsA/Cn ternary complex, determined to a resolution of 3.1 A. Residues 3-9 of CsA, particularly N-methyl leucines 4 and 6, and Trp-121 of Cyp form a composite surface for interaction with Cn. The hydrophobic interface buries two hydrogen bonds. The structure accounts clearly for the effects of mutations in Cn on CsA-resistance and for the way modifications of CsA alter immunosuppressive activity.
Department of Molecular and Cellular Biology, and Howard Hughes Medical Institute, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA.