High impact information on PPIB

• To know whether CyPB might also participate in the delivery of CsA into the brain, we have analyzed the interactions of CyPB with brain capillary endothelial cells [1].
• Receptor-mediated transcytosis of cyclophilin B through the blood-brain barrier [1].
• First, we demonstrated that CyPB binds to two types of binding sites present at the surface of capillary endothelial cells from various species of tissues [1].
• In previous works, we demonstrated that CyPB interacts with T lymphocytes and enhances in vitro cellular incorporation and activity of CsA [1].
• Cyclophilin-B is an abundant protein whose conformation is similar to cyclophilin-A [2].

Biological context of PPIB

• One of the binding proteins was identified by SDS-PAGE and N-terminal amino acid sequence analysis to be cyclophilin B (Cyp B) [3].

Associations of PPIB with chemical compounds

• Bovine cyclophilin-B possesses the peptidylproline cis-trans isomerase activity which is inhibited by nM concentrations of CsA. bCyP-20 has a strong tendency to bind to cation exchangers including DNA and heparin [2].
• In these conditions, CyPB did not significantly modify the passage of CsA, indicating that it is unlikely to provide a pathway for CsA brain delivery [1].
• Induction or repression of the cypB gene also did not effect sensitivity of A. nidulans to cyclosporin A. cypB mRNA levels were significantly elevated under severe heat shock conditions, indicating a possible role for the A. nidulans cyclophilin B protein during growth in high stress environments [4].
• The refolding yields of BCA II assisted by wild-type TF and TF mutants which lack PPIase activity are about the same, which provides further experimental evidence that the PPIase and chaperone activities of TF are independent [5].

Analytical, diagnostic and therapeutic context of PPIB

• Cyclophilin-B (bCyP-20) was isolated in a relatively high quantity from calf brain and spleen tissues consecutively applying weak cation exchange, chromatofocusing and strong cation exchange chromatographies [2].
• Sequence analysis of the cypB gene predicts an encoded protein with highest homology to the murine cyclophilin B protein [4].
• Molecular cloning and characterization of Aspergillus nidulans cyclophilin B [4].

References