Endoproteolytic processing of the mammalian prion glycoprotein family

FEBS J. 2014 Feb;281(3):862-76. doi: 10.1111/febs.12654. Epub 2013 Dec 23.

Abstract

Cellular prion protein (PrP(C)) misfolds to form infectivity-associated scrapie prion protein and generates C-terminal fragments C1 and C2 in healthy and prion-infected animals. C1 cleavage occurs N-terminally of PrP(C)'s hydrophobic domain, whereas the larger C2 fragment is generated by cleavage at the end of the octarepeat region. As the PrP-like proteins Doppel and Shadoo (Sho) have been reported to inhabit similar membrane environments as PrP(C), we investigated endoproteolysis by using a panel of mutant alleles. Doppel undergoes efficient in vivo cleavage at a C1 site mapped to the start of the globular domain, which is a structurally similar cleavage site to that in PrP(C). Sho is processed to C1 and C2 fragments, and proved refractory to mutagenesis to inactivate C1 cleavage. As a reciprocal product of C1 cleavage, Sho also engenders a metabolically stable N1 fragment with a C-terminus after its hydrophobic domain, an observation that may account for N1's association with membrane and/or cellular fractions in vitro and in vivo. Our data indicate that glycosylation status and yet to be identified proteases modulate internal C1 and C2 proteolysis events within the mammalian prion protein family.

Keywords: ADAM; Doppel; Shadoo; endoproteolysis; prion protein.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / enzymology
  • Brain / metabolism
  • Cell Line
  • Endopeptidases / metabolism*
  • GPI-Linked Proteins / chemistry
  • GPI-Linked Proteins / genetics
  • GPI-Linked Proteins / metabolism
  • Glycoproteins / chemistry
  • Glycoproteins / genetics
  • Glycoproteins / metabolism*
  • Glycosylation
  • Male
  • Mice
  • Mice, Transgenic
  • Mutant Proteins / chemistry
  • Mutant Proteins / metabolism
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Neurons / enzymology
  • Neurons / metabolism*
  • Peptide Fragments / chemistry
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • PrPC Proteins / chemistry
  • PrPC Proteins / genetics
  • PrPC Proteins / metabolism*
  • Prions / chemistry
  • Prions / genetics
  • Prions / metabolism*
  • Protein Processing, Post-Translational
  • Protein Structure, Tertiary
  • Proteolysis
  • Rabbits
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism
  • Testis / enzymology
  • Testis / metabolism

Substances

  • GPI-Linked Proteins
  • Glycoproteins
  • Mutant Proteins
  • Nerve Tissue Proteins
  • Peptide Fragments
  • PrPC Proteins
  • Prions
  • Prnd protein, mouse
  • Recombinant Fusion Proteins
  • Shadoo protein, mouse
  • Endopeptidases