PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. [protein]-peptidylproline (omega=180) = [protein]-peptidylproline (omega=0) Induced by ER stress caused by treatment with tunicamycin. Belongs to the cyclophilin-type PPIase family. PPIase B subfamily.