N-Terminal Segment of CyP2 Cyclophilin from Is Involved in Self-Association, Membrane Interaction, and Subcellular Localization.

In (), cyclophilins play a vital role in dislodging Myb proteins from the membrane compartment and leading them to nuclear translocation. We previously reported that CyP1 cyclophilin from forms a dimer and plays an essential role in moving the Myb1 transcription factor toward the nucleus. In comparison, CyP2 containing an extended segment at the N-terminus (N-terminal segment) formed a monomer and showed a different role in regulating protein trafficking.

Endomembrane Protein Trafficking Regulated by a TvCyP2 Cyclophilin in the Protozoan Parasite, Trichomonas vaginalis.

In Trichomonas vaginalis, the TvCyP1-catalyzed conformational switches of two glycinyl-prolyl imide bonds in Myb3 were previously shown to regulate the trafficking of Myb3 from cytoplasmic membrane compartments towards the nucleus. In this study, TvCyP2 was identified as a second cyclophilin that binds to Myb3 at the same dipeptide motifs. The enzymatic proficiency of TvCyP2, but not its binding to Myb3, was aborted by a mutation of Arg in the catalytic domain.

H, C and N resonance assignments and secondary structures of cyclophilin 2 from Trichomonas vaginalis.

Cyclophilins are peptidyl prolyl isomerases that play an important role in a wide variety of biological functions like protein folding and trafficking, intracellular and extracellular signaling pathways, nuclear translocation and in pre-mRNA splicing. Two cyclophilins have been identified in the parasitic organism Trichomonas vaginalis and were named as TvCyP1 and TvCyP2. The 2 enzymes have been found to interact with Myb transcription factors in the parasite which regulate the iron induced expression of ap65-1 gene leading to cytoadherence of the parasite to human vaginal epithelial cells to cause the disease trichomoniasis.