Description
Cyclophilins belong to the superfamily of immunophilins, highly conserved cytoplasmic proteins which share the PPI enzymatic activity and the ability to bind immunosuppressive drugs. CypA binds to and mediates the effect of Cyclosporin A; the CsA/CypA complex selectively binds and inactivates the serine/theronine phosphatase calcineurin leading to disruption of T-cells activating cascade. CsA binding occurs at the active site of the protein thus inhibiting its enzymatic activity. CypA has been demonstrated to be involved in several steps of viral infections such as those mediated by HIV, HBV and HCV.Cyclophilin A (CypA, 18 kDa) is the first peptidyl-prolil cis-trans isomerase (PPIase) to be discovered; PPIases catalyze the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and accelerate the folding of proteins.
