title: Phosphorylation of prion protein at serine 43 induces prion protein conformational change.
abstract: The cause of the conformational change of normal cellular prion protein (PrP) into its disease-associated form is unknown. Posttranslational modifications, such as glycosylation, acetylation, S-nitrosylation, and phosphorylation, are known to induce protein conformational changes. Here, we investigated whether phosphorylation could induce the conformational change of PrP because PrP contains several kinase motifs and has been found recently in the cytosol, in which kinases generally reside. Neuronal cyclin-dependent kinase 5 (Cdk5) phosphorylated recombinant PrP(23-231) at serine 43 (S43) in an in vitro kinase assay. Cdk5-phosphorylated PrP became proteinase K resistant, formed Congo Red-positive fibrils, and formed aggregates that were immunostained with anti-PrP and anti-phospho-PrP(S43) (anti-pPrP(S43)). pPrP(S43) was detected in PrP/Cdk5/p25 cotransfected N2a cells. Roscovitine inhibition of Cdk5 activity or transfection of N2a cells with mutant PrP S43A eliminated the anti-pPrP(S43)-immunopositive protein. Alkaline phosphatase-sensitive and proteinase K-resistant pPrP(S43) immunoreactivity was observed in scrapie-infected but not control-injected mice brains. These results raise the possibility that phosphorylation could represent a physiological mechanism of PrP conversion in vivo.
authors: The Bloomfield Centre for Research in Aging, Lady Davis Institute for Medical Research, The Sir Mortimer B. Davis Jewish General Hospital, Montréal, Québec H3T 1E2, Canada.
authors: Paresa N
authors: PN
authors: Giannopoulos
authors: Catherine
authors: C
authors: Robertson
authors: Julie
authors: J
authors: Jodoin
authors: Hemant
authors: H
authors: Paudel
authors: Stephanie A
authors: SA
authors: Booth
authors: Andrea C
authors: AC
authors: LeBlanc
mesh_terms: D000818:Animals; D002417:Cattle; D045744:Cell Line, Tumor; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000235:genetics; D011328:Prions / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D012694:Serine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D011328:Prions; C428437:prion protein (23-231); D012694:Serine