Cyclophilin-40, a protein with homology to the P59 component of the steroid receptor complex. Cloning of the cDNA and further characterization

• Published in: The Journal of biological chemistry 1993-06, Vol.268 (17), p.12303-12310
• Main Authors: KIEFFER, L. J, SENG, T. W, WEI LI, OSTERMAN, D. G, HANDSCHUMACHER, R. E, BAYNEY, R. M
• Format: Article
• Language: English
• Subjects: Amino Acid Isomerases - chemistry; Amino Acid Isomerases - genetics; Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Base Sequence; Binding and carrier proteins; Biological and medical sciences; Brain - metabolism; Carrier Proteins - chemistry; Carrier Proteins - genetics; Cattle; cDNA; Cloning, Molecular; cyclophilin-40; Cyclophilins; Cyclosporine - metabolism; DNA; Fundamental and applied biological sciences. Psychology; genes; homology; Humans; man; Molecular Sequence Data; nucleotide sequence; Oligodeoxyribonucleotides; P59 component; pancreas; Pancreas - metabolism; Peptidyl-Prolyl Isomerase F; Peptidylprolyl Isomerase; Proteins; receptors; Receptors, Steroid - chemistry; Sequence Homology, Amino Acid; steroids
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)31389-9

We have reported previously the isolation and preliminary characterization of a 40-kDa cyclosporin A (CsA)-binding protein, cyclophilin-40 (CyP-40). To determine the sequence of this protein, degenerate oligonucleotide primers based on bovine brain CyP-40 tryptic peptides were used to generate a polymerase chain reaction fragment of CyP-40 cDNA. This was used to isolate the complete cDNA from a human pancreatic islet cell library. Northern analysis indicated ubiquitous distribution of CyP-40 mRNA throughout human tissues. The CyP-18 domain of CyP-40 is most similar to maize CyP (64.3% identity), whereas 150 amino acids of the non-CyP-18 domain of CyP-40 share 30.7% identity with P59, a member of the steroid receptor complex. Failure to detect glycosylation and mass spectroscopy with isolated CyP-40 indicate minimal, if any, posttranslational modification. Employing a new assay for calcineurin protein phosphatase activity to compare the effects of CyP-40.CsA and CyP-18.CsA complexes, IC50 values of 320 nM +/- 20 and 195 nM +/- 15, respectively, were obtained. A chemical cross-linking study revealed that CyP-40 competes for 125I-CyP-18 binding to calcineurin in the presence of CsA. The homology of CyP-40 to P59 suggests that CyP-40 might be involved in modulating the activity of biologically important receptors.