Cyclophilin

Cyclophilins are enzymes that accelerate the rotation of the peptide bond in front of a proline residue. Cyclophilins are involved in a wide variety of cellular processes such as folding, posttranslational modifications and transport of proteins, assembly of essential cellular protein complexes, and cell signaling. Cyclophilins have been identified in a range of organisms, including mammals, plants, insects, fungi, and bacteria.

The prototypic cyclophilin A (CypA) is the most abundant member of the cyclophilin family in human tissue and the major player in the cellular PPIase activity. CypA as a host cell protein interacts with viral proteins and can thus promote or inhibit viral replication and infection of a variety of RNA viruses, most prominently HIV‐1 and HCV.