| First Author | Friedman J | Year | 1991 |
| Journal | Cell | Volume | 66 |
| Issue | 4 | Pages | 799-806 |
| PubMed ID | 1652374 | Mgi Jnum | J:17287 |
| Mgi Id | MGI:65336 | Doi | 10.1016/0092-8674(91)90123-g |
| Citation | Friedman J, et al. (1991) Two cytoplasmic candidates for immunophilin action are revealed by affinity for a new cyclophilin: one in the presence and one in the absence of CsA. Cell 66(4):799-806 |
| abstractText | We report the cloning and characterization of a new binding protein for the immunosuppressive drug cyclosporin A (CsA). This new cyclophilin, cyclophilin C (cyp C), shows extensive homology with all previously identified cyclophilins. Cyp C mRNA is expressed in a restricted subset of tissues relative to cyclophilins A and B, but is present in those tissues reported to be most affected by CsA therapy. A cyp C fusion protein has peptidyl-prolyl isomerase activity, and CsA inhibits this activity. Using the cyp C fusion protein as an affinity ligand to probe cellular extracts, we find that the cyp C fusion protein binds specifically to a 77 kd protein in the absence of CsA, while in the presence of CsA it instead binds specifically to a 55 kd protein. We propose that the p77 is involved in cyp C native function and that the p55 is involved in signal transduction events blocked by treatment with immunosuppressive levels of CsA. |
