Cyclophilin A, also named as PPIA and Rotamase A, belongs to the cyclophilin-type PPIase family and PPIase A subfamily.PPIases accelerate the folding of proteins.It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. PPIA forms a trimolecular complex with cyclophilin and calcineurins to inhibit calcineurin phosphatase activity. The encoded protein is a cyclosporin binding-protein and may play a role in cyclosporin A-mediated immunosuppression.