title: Three-dimensional structure and actions of immunosuppressants and their immunophilins.
abstract: The use of the immunosuppressant drug cyclosporin A (CsA) as a biochemical tool to study the signal transduction pathway in T cells has led to the discovery of a first family of immunosuppressant-binding proteins or "immunophilins," the cyclophilins (Cyp). Another, chemically unrelated immunosuppressant molecule, FK506, was then found to be related to a second class of immunophilins, the FK506-binding proteins (FKBPs). This paper reviews the existing structural information on these immunophilins in the context of present knowledge of the biochemical mechanisms for immunosuppression. The formation of Cyp-CsA and FKBP-FK506 complexes, and the subsequent specific interaction of these complexes with the serine/threonine phosphatase calcineurin (CN), are key steps in the cascade of events that result in the desired immunosuppression. Knowledge of the conformation of the Cyp-CsA-CN and FKBP-FK506-CN ternary complexes is of significant biomedical interest, because mimics of the composite contact surfaces of, for example, Cyp-CsA or FKBP-FK506, could provide immunosuppressant drugs with improved pharmacological profiles.
authors.affiliation: Institut für Molekularbiologie und Biophysik, ETH-Hönggerberg, Zürich, Switzerland.
authors.forename: W
authors.initials: W
authors.lastname: Braun
authors.forename: J
authors.initials: J
authors.lastname: Kallen
authors.forename: V
authors.initials: V
authors.lastname: Mikol
authors.forename: M D
authors.initials: MD
authors.lastname: Walkinshaw
authors.forename: K
authors.initials: K
authors.lastname: Wüthrich
mesh_terms: D000591:Amino Acid Isomerases / Q000737:chemistry / Q000378:metabolism; D019703:Calcineurin; D002148:Calmodulin-Binding Proteins / Q000037:antagonists & inhibitors; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D016572:Cyclosporine / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007166:Immunosuppressive Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D008958:Models, Molecular; D019696:Peptidylprolyl Isomerase; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D016559:Tacrolimus / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D022021:Tacrolimus Binding Proteins
chemical_list: D002148:Calmodulin-Binding Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; D007166:Immunosuppressive Agents; D016572:Cyclosporine; D019703:Calcineurin; D010749:Phosphoprotein Phosphatases; D000591:Amino Acid Isomerases; D022021:Tacrolimus Binding Proteins; D019696:Peptidylprolyl Isomerase; D016559:Tacrolimus