High impact information on PPIC

• Cyclophilin C-associated protein: a normal secreted glycoprotein that down-modulates endotoxin and proinflammatory responses in vivo [1].
• We report the protein purification and the cloning and characterization of a cDNA encoding the proteins that bind with high affinity to cyclophilin C (Cyp-C) in the absence of cyclosporin A [2].
• In contrast, cyclophilin C, FKBP13, and FKBP25 had no effect [3].
• When added to nuclei from nonapoptotic cells, cyclophilin C induces 50-kilobase pair DNA fragmentation but not internucleosomal fragmentation [4].
• The relative affinity of Cyp-C for CsA is lower by a factor of 2 than that of Cyp-A, which itself is 10-fold lower than that of Cyp-B [5].

Biological context of PPIC

• Human cyclophilin C: primary structure, tissue distribution, and determination of binding specificity for cyclosporins [5].
• A complementary DNA (cDNA) for human cyclophilin C (Cyp-C) was isolated from a human kidney cDNA library [5].

Anatomical context of PPIC

• Northern blot experiments with several human tissues and cell lines revealed that Cyp-C is less abundant than Cyp-A [5].
• Expression of human Cyp-C in the kidney is not significantly elevated compared to pancreas, skeletal muscle, heart, lung, and liver [5].
• Preparative continuous free flow-isoelectric focusing has been used to separate at least three different components of intrinsic peptidyl-prolyl cis/trans isomerase (PPIase) activity from erythrocytes lysate [6].

Associations of PPIC with chemical compounds

• This argues against a previously postulated specific role for Cyp-C in the nephrotoxic effects of CsA in humans, based on the studies of its relative abundance in murine kidney [5].
• Based on the structures of chorismate mutase and cyclophilin C, the ratio of >1.2 for the average magnitudes of parity groups is sufficient to indicate the existence of pseudo-translation [7].

Other interactions of PPIC

• The plasma levels of D-dimer, soluble fibrin monomer, thrombomodulin, TF and PPIC were significantly decreased 1 hr, and the plasma levels of plasmin-alpha2 antiplasmin inhibitor complex 1 day after PTCA [8].

Analytical, diagnostic and therapeutic context of PPIC

• The recent demonstration that cyclophilin is a CsA-sensitive prolyl-peptidyl-isomerase (PPIase), has prompted speculation that CsA immunosuppression is mediated by PPIase interaction with activation signals like ADR [9].
• Circular dichroism spectroscopy indicates that the secondary structure of the cationic protein consists of 17% alpha-helix, 34% beta-sheet, 17% turns, 33% random coil and is very similar to human cytosolic PPIase [10].

References