PPID Protein, Human (His)

PPID Protein serves as a peptidyl-prolyl cis-trans isomerase (PPIase), catalyzing the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and potentially aiding in protein folding processes. Proposed to act as a co-chaperone in HSP90 complexes, particularly in unligated steroid receptors heterocomplexes, PPID contributes to the dynamic regulation of HSP90-co-chaperone-receptor complexes. This involvement suggests a role in tissue-specific control of receptor activity, with a potential preference for estrogen receptor complexes over glucocorticoid receptor complexes. Moreover, PPID may participate in the cytoplasmic dynein-dependent movement of receptors from the cytoplasm to the nucleus. Notably, it is implicated in regulating MYB by inhibiting its DNA-binding activity and plays a role in AHR signaling by promoting the formation of the AHR:ARNT dimer, independently of HSP90 but requiring chaperone activity. Additionally, PPID is involved in the regulation of UV radiation-induced apoptosis and promotes cell viability in anaplastic lymphoma kinase-positive anaplastic large-cell lymphoma (ALK+ ALCL) cell lines. In the context of microbial infection, PPID may be associated with hepatitis C virus (HCV) replication and release.