PPIase is a member of the immunophilin protein family. It also belongs to the cyclophilin-type PPIase family, PPIL3 subfamily. PPIase contains 1 PPIase cyclophilin-type domain. Members of the immunophilin protein family play a role in immunoregulation and basic cellular processes involving protein folding and trafficking. PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. It has a very high substrate specificity for the four-residue peptide Ala-Ala-Pro-Phe only when the proline peptide bond is in the trans state. It interacts with several intracellular signal transduction proteins including type I TGF-beta receptor. It also interacts with multiple intracellular calcium release channels, and coordinates multi-protein complex formation of the tetrameric skeletal muscle ryanodine receptor. In mouse, deletion of this homologous gene causes congenital heart disorder known as noncompaction of left ventricular myocardium.