PrP106-126Inhibit The Formation Of14-3-3Dimer

Prion diseases, also known as transmissible spongiform encephalopathies (TSEs), are fatal progressive neurodegenerative diseases in humans and animals and include Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler-Scheinker syndrome (GSS), fatal familial insomnia (FFI), and kuru in humans, scrapie in sheep, and bovine spongiform encephalopathy (BSE) in cattle. A critical event in pathogenesis appears to be the conversion of protease-sensitive prion protein (PrPC) to its protease-resistant isoform (PrPSc), which involves a conformational change in PrP from having high a-helix to high P-sheet content. A related peptide consisting of amino acids106-126exhibits a P-sheet structure in water and is able to form amyloid-like fibrils in vitro and display neurotoxic activity in primary cultures of rat hippocampal neurons as well as many other cell lines It is considered to be an important tool to reveal the mechanisms of PrPSc toxicity. As a result, PrP (106-126) becomes a suitable model of prion to research it’s pathogenicity on cells.The CSF14-3-3protein is frequently detected in patients with CJD, especially sporadic CJD (sCJD), Therefore. CSF14-3-3protein positivity western blotting is accepted as a laboratory criterion for the diagnosis of sCJD. However, the exact role played by14-3-3proteins in the pathogenesis of prion diseases remains unclear. The14-3-3proteins comprise a family of abundant and widely expressed acidic polypeptides in all eukaryotic cells; they act as either homo-or heterodimers The14-3-3proteins form complexes with multiple protein ligands, e.g., Raf-1, Bad, Bax, and Cdc25, and are involved in various cellular functions such as cell division, nuclear transport, apoptosis, and differentiation. To investigate both PrP and PrP106-126peptide effect on14-3-3β dimeration,14-3-3β were incubated with different does recombinant PrP protein, PrP106-126peptide, and PrP106-126K110G peptide respectively, both14-3-3β dimer and polymer were separated15%non-denaturing polyacrylamide gel electrophoresis (PAGE) and the14-3-3dimers. were evaluated using14-3-3β-specific western blotting. Results showed recombinant full-length PrP facilitated the dimerization of14-3-3in vitro, the PrP106-126peptide inhibited the the dimerization of14-3-3β with dose-dependent effect in vitro. The PrP106-126K110G peptide did not inhibit the dimerization of14-3-3β in vitro. PrP antagonized PrP106-126-induced14-3-3β dimer disaggregation in vitro. Treatment of peptide PrP106-126on HeLa cells efficiently inhibited cellular14-3-3dimerization and dissociated Bax to translocate to membrane and induced cellular apoptosis. However, treatment of peptide PrP106-126K110G on HeLa ceils did not also inhibited cellular14-3-3dimerization. Thus14-3-3dimeration may be critical to both PrPC neuroprotection and PrPSc neurotoxicity events, causing the morphological and cytological changes that promote the development of prion disease.