PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides (By similarity). Involved in plant response to pathogen infection by increasing PAD4 expression in absence of EDS1 up-regulation. [protein]-peptidylproline (omega=180) = [protein]-peptidylproline (omega=0) Ubiquitous. Up-regulated upon pathogen infection. Increased susceptibility to P.syringae infection. Belongs to the cyclophilin-type PPIase family.