PPIases accelerate the folding of proteins by catalyzing the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. [protein]-peptidylproline (omega=180) = [protein]-peptidylproline (omega=0) Inhibited by both FK506 and rapamycin. Highly expressed in growing cells. Expression levels decrease during the first few hours of development. Belongs to the FKBP-type PPIase family.