title: Endoproteolytic processing of the mammalian prion glycoprotein family.
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.
authors.affiliation: Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Canada.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Mays
authors.forename: Janaky
authors.initials: J
authors.lastname: Coomaraswamy
authors.forename: Joel C
authors.initials: JC
authors.lastname: Watts
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Kerry W S
authors.initials: KW
authors.lastname: Ko
authors.forename: Bob
authors.initials: B
authors.lastname: Strome
authors.forename: Robert C C
authors.initials: RC
authors.lastname: Mercer
authors.forename: Serene L
authors.initials: SL
authors.lastname: Wohlgemuth
authors.forename: Gerold
authors.initials: G
authors.lastname: Schmitt-Ulms
authors.forename: David
authors.initials: D
authors.lastname: Westaway
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology / Q000378:metabolism; D002460:Cell Line; D010450:Endopeptidases / Q000378:metabolism*; D058851:GPI-Linked Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018621:PrPC Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011328:Prions / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D059748:Proteolysis; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D013737:Testis / Q000201:enzymology / Q000378:metabolism
chemical_list: D058851:GPI-Linked Proteins; D006023:Glycoproteins; D050505:Mutant Proteins; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; D018621:PrPC Proteins; D011328:Prions; C122036:Prnd protein, mouse; D011993:Recombinant Fusion Proteins; C523856:Sprn protein, mouse; D010450:Endopeptidases
keywords: ADAM; Doppel; Shadoo; endoproteolysis; prion protein