title: Cyclophilin-40: evidence for a dimeric complex with hsp90.
abstract: The expression of human cyclophilin 40 (CyP-40) as a glutathione S-transferase fusion protein has provided a means to identify cellular components that are in association with this ubiquitous protein. When the fusion protein was coupled to a GSH affinity matrix, heat-shock protein 90 (hsp90) was found to be the predominant associated protein in all tissue extracts examined. The relatively high concentration of each of these proteins in various tissues indicates that the dimeric complex exists in concentrations that exceed those of the inactive steroid receptors of which each protein is a component. Association does not occur with heat-shock protein 70 and is not affected by cyclosporin A (CsA). Independent expression of two domains of CyP-40 permitted dissociation of N-terminal isomerase and CsA binding activity from the hsp90 binding site, which is located at the FKBP-59-like C-terminal region. The biological association of CyP-40 with hsp90 in many tissues may reflect a conjoint role in protein folding and trafficking.
authors.affiliation: Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA.
authors.forename: K
authors.initials: K
authors.lastname: Hoffmann
authors.forename: R E
authors.initials: RE
authors.lastname: Handschumacher
mesh_terms: D000591:Amino Acid Isomerases / Q000276:immunology / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D002352:Carrier Proteins / Q000276:immunology / Q000378:metabolism*; D000081406:Peptidyl-Prolyl Isomerase F; D021983:Cyclophilins; D016572:Cyclosporine / Q000494:pharmacology; D005982:Glutathione Transferase / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000494:pharmacology; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D019696:Peptidylprolyl Isomerase; D011485:Protein Binding; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D000081406:Peptidyl-Prolyl Isomerase F; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D011993:Recombinant Fusion Proteins; D016572:Cyclosporine; D005982:Glutathione Transferase; D000591:Amino Acid Isomerases; D021983:Cyclophilins; D019696:Peptidylprolyl Isomerase