Genetic mapping of activity determinants within cellular prion proteins: N-terminal modules in PrPC offset pro-apoptotic activity of the Doppel helix B/B' region

J Biol Chem. 2004 Dec 31;279(53):55443-54. doi: 10.1074/jbc.M404794200. Epub 2004 Sep 29.


The PrP-like Doppel (Dpl) protein causes apoptotic death of cerebellar neurons in transgenic mice, a process prevented by expression of the wild type (wt) cellular prion protein, PrP(C). Internally deleted forms of PrP(C) resembling Dpl such as PrPDelta32-121 produce a similar PrP(C)-sensitive pro-apoptotic phenotype in transgenic mice. Here we demonstrate that these phenotypic attributes of wt Dpl, wt PrP(C), and PrPDelta132-121 can be accurately recapitulated by transfected mouse cerebellar granule cell cultures. This system was then explored by mutagenesis of the co-expressed prion proteins to reveal functional determinants. By this means, neuroprotective activity of wt PrP(C) was shown to be nullified by a deletion of the N-terminal charged region implicated in endocytosis and retrograde axonal transport (PrPDelta23-28), by deletion of all five octarepeats (PrPDelta51-90), or by glycine replacement of four octarepeat histidine residues required for selective binding of copper ions (Prnp"H/G"). In the case of Dpl, overlapping deletions defined a requirement for the gene interval encoding helices B and B' (DplDelta101-125). These data suggest contributions of copper binding and neuronal trafficking to wt PrP(C) function in vivo and place constraints upon current hypotheses to explain Dpl/PrP(C) antagonism by competitive ligand binding. Further implementation of this assay should provide a fuller understanding of the attributes and subcellular localizations required for activity of these enigmatic proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Animals
  • Apoptosis*
  • Cell Death
  • Cell Line, Tumor
  • Cerebellum / metabolism
  • Chromosome Mapping
  • Copper
  • DNA Mutational Analysis
  • Endocytosis
  • GPI-Linked Proteins
  • Gene Deletion
  • Glycine / chemistry
  • Green Fluorescent Proteins / metabolism
  • Ions
  • Mice
  • Mice, Transgenic
  • Microscopy, Fluorescence
  • Models, Genetic
  • Mutation
  • Neurons / metabolism
  • Neurons / pathology
  • Phenotype
  • Plasmids / metabolism
  • Point Mutation
  • PrPC Proteins / chemistry
  • PrPC Proteins / genetics*
  • PrPC Proteins / physiology*
  • Prions / chemistry
  • Prions / genetics*
  • Prions / physiology*
  • Protein Binding
  • Protein Structure, Tertiary
  • Transfection
  • Transgenes


  • GPI-Linked Proteins
  • Ions
  • PrPC Proteins
  • Prions
  • Prnd protein, mouse
  • Green Fluorescent Proteins
  • Copper
  • Glycine