PPIB encodes peptidylprolyl isomerase B (cyclophilin B), a crucial enzyme with peptidyl-prolyl cis-trans isomerase activity that assists in protein folding through catalyzing cis-trans isomerization of proline residues 1. The protein functions as a collagen chaperone, forming a bifunctional reaction center with P3H1 in the P3H1/CRTAP/PPIB ternary complex essential for collagen posttranslational processing 1. PPIB operates through coupled modification mechanisms and can form dual-ternary complexes, with activity regulated by active site mutations and inhibitors 1. Disease relevance includes significant associations with osteogenesis imperfecta, where disruption of the collagen processing machinery leads to tissue development disorders 1. Additionally, PPIB contributes to pathological processes including renal fibrosis following acute kidney injury 2, serves as a potential biomarker in COPD with upregulated expression correlating with disease progression 3, and promotes tumor progression in lung adenocarcinoma and ovarian cancer through various mechanisms including mRNA stabilization 45. Clinically, PPIB represents a therapeutic target for fibrotic diseases, as demonstrated by sanglifehrin A's antifibrotic effects through cyclophilin B inhibition and secretion induction 6, and shows promise as a biomarker for heterotopic ossification 7.