Cyclophilin peptidyl-prolyl isomerase (Cyp)

Cyclophilin peptidyl-prolyl isomerases are a large family of enzymes (immunophilins) found ubiquitously in prokaryotes and eukaryotes. They catalyze the rate-limiting cis-trans isomerization of peptide bonds at proline residues, thereby accelerating protein folding and influencing the assembly and function of multidomain proteins. Cyclophilins also act as molecular chaperones, participate in intracellular signaling, immune regulation, apoptosis, and cell migration. Their extracellular secretion contributes to inflammatory signaling. Cyclophilins are therapeutic targets for drugs such as cyclosporin, which inhibit their enzymatic activity and suppress immune responses critical for organ transplantation and autoimmune diseases. Dysregulation or overexpression of cyclophilins is implicated in neurodegenerative disorders, cancer, cardiovascular disease, infection, and aging. Specific isoforms, especially cyclophilin A (CypA), play pivotal roles in disease mechanisms and are being explored as biomarkers and drug targets.

Other names

Peptidylprolyl isomeraseCyclophilin ACyclophilin BRotamaseImmunophilin

Enzyme inhibition (Drug binds to cyclophilin active site, blocking peptidyl-prolyl isomerase activity); Immunosuppression (CsA-cyclophilin complex inhibits calcineurin phosphatase, suppressing T-cell activation)