PPIases accelerate the folding of proteins (Probable). It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides (PubMed:33098102). Histone proline isomerase that increases the rate of cis-trans isomerization of the synthetic histone H3 peptides H3P30 (RKSAP30F-p-nitroanilide) and H3P30K27me3 (RKme3-SAP30F-p-nitroanilide) in the histone H3 N-terminal tail, in vitro (PubMed:33098102). Histone remodeling factor involved in chromatin-based gene silencing (PubMed:17704213). Reinforces H3K27 methylation (PubMed:17704213). Involved in fundamental processes of chromatin assembly and histone modification by mediating the targeting of FAS1 and LHP1 on the chromatin (PubMed:21596687). Required for the formation and development of leaves, for normal phyllotaxy and for the formation, maintenance and activity of root and shoot apical meristems (PubMed:17704213). [protein]-peptidylproline (omega=180) = [protein]-peptidylproline (omega=0) Interacts with FAS1 and LHP1 (PubMed:21596687). Interacts (via WD repeat domain) with histone H3 (PubMed:17704213). Ubiquitous. Expressed in the meristems. Down-regulated by auxin treatment. Bushy and stunted stature. Belongs to the cyclophilin-type PPIase family.