Peptidylprolyl-cis/trans-isomerase (PPIase); specific for phosphorylated SP and TP residues; regulates Rpo21p CTD  phosphorylation at Ser7; associates with the phospho-Ser5 form of RNAPII; present along entire coding length of genes; represses initiation of CUTs; required for mRNA transcription termination and histone H3 trimethylation; represses TERRA transcription, R-loop abundance and regulates telomere replication by promoting DNA-end resection; human ortholog PIN1 complements yeast mutants