Peptidylprolyl Isomerase E (PPIE)

Peptidyl-prolyl cis-trans isomerase E is  a member of the peptidyl-prolyl cis-trans isomerase (PPIase) family. PPIases catalyze the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and accelerate the folding of proteins. This protein contains a highly conserved cyclophilin (CYP) domain as well as an RNA-binding domain. It was shown to possess PPIase and protein folding activities and also exhibit RNA-binding activity. Three alternatively spliced transcript variants encoding distinct isoforms have been observed.

The PPIase activity of CYP33 is inhibited by CsA with kinetics similar to other CYPs. Northern blotting of T-cell mRNA revealed expression of a low abundance 1.6-kb CYP33 transcript.