title: Characterization of spontaneously generated prion-like conformers in cultured cells.
abstract: A distinct conformational transition from the α-helix-rich cellular prion protein (PrPC) into its β-sheet-rich pathological isoform (PrPSc) is the hallmark of prion diseases, a group of fatal transmissible encephalopathies that includes spontaneous and acquired forms. Recently, a PrPSc-like intermediate form characterized by the formation of insoluble aggregates and protease-resistant PrP species termed insoluble PrPC (iPrPC) has been identified in uninfected mammalian brains and cultured neuronal cells, providing new insights into the molecular mechanism(s) of these diseases. Here, we explore the molecular characteristics of the spontaneously formed iPrPC in cultured neuroblastoma cells expressing wild-type or mutant human PrP linked to two familial prion diseases. We observed that although PrP mutation at either residue 183 from Thr to Ala (PrPT183A) or at residue 198 from Phe to Ser (PrPF198S) affects glycosylation at both N-linked glycosylation sites, the T183A mutation that results in intracellular retention significantly increased the formation of iPrPC. Moreover, while autophagy is increased in F198S cells, it was significantly decreased in T183A cells. Our results indicate that iPrPC may be formed more readily in an intracellular compartment and that a significant increase in PrPT183A aggregation may be attributable to the inhibition of autophagy.
authors: Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA.
authors: Roger S
authors: RS
authors: Zou
authors: Hisashi
authors: H
authors: Fujioka
authors: Jian-Ping
authors: JP
authors: Guo
authors: Xiangzhu
authors: X
authors: Xiao
authors: Miyuki
authors: M
authors: Shimoji
authors: Crystal
authors: C
authors: Kong
authors: Cecilia
authors: C
authors: Chen
authors: Megan
authors: M
authors: Tasnadi
authors: Chesinta
authors: C
authors: Voma
authors: Jue
authors: J
authors: Yuan
authors: Mohammed
authors: M
authors: Moudjou
authors: Hubert
authors: H
authors: Laude
authors: Robert B
authors: RB
authors: Petersen
authors: Wen-Quan
authors: WQ
authors: Zou
mesh_terms: D000465:Algorithms; D000818:Animals; D002478:Cells, Cultured; D015180:Electrophoresis, Gel, Two-Dimensional; D019286:Endopeptidase K / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase / Q000378:metabolism; D008970:Molecular Weight; D009154:Mutation; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / Q000378:metabolism; D011328:Prions / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary
chemical_list: D011328:Prions; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D019286:Endopeptidase K; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase