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) Interacts with HMO1. Interacts with FAP1. Binds to the immunosuppressant drug FK506 and also mediates the sensitivity to rapamycin (PubMed:1996117). Rapamycin disrupts interaction with FAP1. Present with 43300 molecules/cell in log phase SD medium. Belongs to the FKBP-type PPIase family. FKBP1 subfamily.