PMID: 10842180

 

    Legend: Sugar

Title : Doppel is an N-glycosylated, glycosylphosphatidylinositol-anchored protein

Abstract :

1. Expression in testis and ectopic production in the brains of Prnp (0/0) mice predisposed to Purkinje cell loss
2. The Prnd gene encodes a homolog of the cellular prion protein ( PrP ( C )) called doppel ( Dpl )
3. Up-regulation of Prnd mRNA in two distinct lines of PrP gene ablated ( Prnp (0/0)) mice, designated Rcm0 and Ngsk, is associated with death of Purkinje cells
4. Using recombinant Dpl expressed in Escherichia coli and mouse neuroblastoma cells we demonstrate that wild type (wt) Dpl , like PrP ( C ), adopts a predominantly alpha-helical conformation, forms intramolecular disulfide bonds, has two N-linked oligosaccharides , and is presented on the cell surface via a glycosylphosphatidylinositol anchor
5. Dpl protein was detected in testis of wt mice
6. Using Triton X-114 phase partitioning to enrich for glycosylphosphatidylinositol-anchored proteins , Dpl was detected in brain samples from Rcm0 Prnp (0/0) mice but was absent in equivalent samples from wt mice and ZrchI Prnp (0/0) mice, indicating that ectopic expression of this protein may cause cerebellar pathology in Rcm0 mice
7. Biochemical and structural similarities between PrP ( C ) and Dpl documented here parallel the observation that ataxic Ngsk Prnp (0/0) mice can be rescued by overexpression of wild-type PrP transgenes, and suggest that cell surface PrP ( C ) can antagonize the toxic effect of Dpl expressed in the central nervous system