Defective Retrotranslocation Causes Loss of Anti-Bax Function in Human Familial Prion Protein Mutants

Cyclin-dependent Kinase 5 Phosphorylation of Familial Prion Protein Mutants Exacerbates Conversion into Amyloid Structure

“…Furthermore, the ThT-positive amyloid in PrP WT-V or Y145X M and the seeding properties of phosphorylated Q160X M were partially reversible upon dephosphorylation, similar to the reversibility of secretory granule peptide hormone amyloids as they convert to a monomeric ␣-helical form when released (45). None of the phosphorylated full-length PrP mutants investigated showed fibril formation initially and were observed by electron microscopy to possess a globular structure of aggregated proteins (data not shown) as observed previously for wild type PrP (20). Furthermore, the phosphorylated WT PrP did not have the ability to seed PrP conversion in a homologous reaction over a period of 60 h. Lastly, the phosphorylation at Ser 43 of PrP has been detected in normal adult mouse brain synaptic membranes (18).…”

“…The increased rate constant of Cdk5-mediated PrP conversion in the familial PrP mutants may explain the age-dependent manifestation of the prion diseases associated with those mutations. Cdk5-phosphorylated PrP is also increased in mouse transmissible prion disease (20). Furthermore, selective PrP immunoprecipitation from scrapie-infected brains with the 6A12 antibody mapping to amino acids 41-47 (30) suggests an alteration of the N terminus of PrP in prion disease conditions.…”

“…PrP cDNA encoding amino acids 23-231 with either a methionine (PrP WT-M ) or valine (PrP WT-V ) codon 129 was cloned into the XhoI and BamHI restriction sites of pET23b as described (20). QuikChange site-directed mutagenesis was used to generate the single point and truncated mutant PrPs.…”

Pathogenic Mutations in the Hydrophobic Core of the Human Prion Protein Can Promote Structural Instability and Misfolding

“…It is not clear which category V180I PrP belongs to. Thermodynamic stability of recPrP is somewhat affected15 but cell-surface GPI-anchored PrP is generated efficiently,51 suggesting that misfolding happens whilst attached to a membrane. Our simulations indicate that misfolding may happen in a similar fashion as WT PrP, but conformational changes unlike those observed in WT PrP were found as well.…”

Disease-associated Mutations in the Prion Protein Impair Laminin-induced Process Outgrowth and Survival

“…Noteworthy, PrP C mutations associated to CJD, fatal familial insomnia, and Gerstmann-Straussler-Scheinker disease decrease or abolish the anti-bax function in primary human neurons and breast cancer cell lines promoting programmed cell death (34).…”