The protein encoded by this gene is a cyclosporine-binding protein and is mainly located within the endoplasmic reticulum. It is associated with the secretory pathway and released in biological fluids. This protein can bind to cells derived from T- and B-lymphocytes, and may regulate cyclosporine A-mediated immunosuppression. Variants have been identified in this protein that give rise to recessive forms of osteogenesis imperfecta. [provided by RefSeq, Oct 2009],catalytic activity:Peptidylproline (omega=180) = peptidylproline (omega=0).,caution:It is uncertain whether Met-1 or Met-9 is the initiator.,enzyme regulation:Cyclosporin A (CsA) inhibits CYPB.,function:PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides.,similarity:Belongs to the cyclophilin-type PPIase family. PPIase B subfamily.,similarity:Contains 1 PPIase cyclophilin-type domain.,subcellular location:Identified by mass spectrometry in melanosome fractions from stage I to stage IV.,
