Peptidyl-prolyl isomerase A (CypA)

Peptidyl-prolyl isomerase A (CypA), commonly known as cyclophilin A, is an abundant member of the immunophilin family characterized by peptidyl-prolyl cis-trans isomerase activity, which catalyzes the interconversion of proline residues in polypeptide chains and thereby accelerates protein folding[3][5]. CypA plays key roles in protein quality control (chaperone-mediated folding), regulation of intracellular signaling pathways, transcription, cell death, immune response, and angiogenesis[1][3]. As the intracellular receptor for the immunosuppressant cyclosporine, CypA is critical in the suppression of T cell activation during organ transplantation[5]. Cyclophilin A is also implicated in pathologies including viral infection, chronic inflammation, cardiovascular disease, neurodegeneration, and cancer through both its enzymatic and signaling functions[1][3].

Other names

cyclophilin Acyclophilin isomeraserotamase A

Cyclosporine binds to cyclophilin A, forming a complex that inhibits the phosphatase activity of calcineurin involved in T cell activation and immune response suppression[5].