Prion protein with Y145STOP mutation induces mitochondria-mediated apoptosis and PrP-containing deposits in vitro

Naomi S. Hachiya, Kota Watanabe, Makiko Y. Kawabata, Akiko Jozuka, Yoshimichi Kozuka, Yuji Sakasegawa, Kiyotoshi Kaneko

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

A pathogenic truncation of an amber mutation at codon 145 (Y145STOP) in Gerstmann-Straussler-Scheinker disease (GSS) was investigated through the real-time imaging in living cells, by utilizing GFP-PrP constructs. GFP-PrP(1-144) exhibited an aberrant localization to mitochondria in mouse neuroblastoma neuro2a (N2a) and HpL3-4 cells, a hippocampal cell line established from prnp gene-ablated mice, whereas full-length GFP-PrP did not. The aberrant mitochondrial localization was also confirmed by Western blot analysis. Since GFP-PrP(1-121), as previously reported, and full-length GFP-PrP do not exhibit such mitochondrial localization, the mitochondrial localization of GFP-PrP(1-144) requires not only PrP residues 121-144 (in human sequence) but also COOH-terminal truncation in the current experimental condition. Subsequently, the GFP-PrP(1-144) induced a change in the mitochondrial innermembrane potential (ΔΨ m), release of cytochrome c from the intermembrane space into the cytosol, and DNA fragmentation in these cells. Non-fluorescent PrP(1-144) also induced the DNA fragmentation in N2a and HpL3-4 cells after the proteasomal inhibition. These data may provide clues as to the molecular mechanism of the neurotoxic property of Y145STOP mutation. Furthermore, immunoelectron microscopy revealed numerous electron-dense deposits in mitochondria clusters of GFP-PrP(1-144)-transfected N2a cells, whereas no deposit was detected in the cells transfected with full-length GFP-PrP. Co-localization of GFP/PrP-immunogold particles with porin-immunogold particles as a mitochondrial marker was observed in such electron-dense vesicular foci, resembling those found in autophagic vacuoles forming secondary lysosomes. Whether such electron-dense deposits may serve as a seed for the growth of amyloid plaques, a characteristic feature of GSS with Y145STOP, awaits further investigations.

Original languageEnglish
Pages (from-to)894-899
Number of pages6
JournalBiochemical and biophysical research communications
Volume327
Issue number3
DOIs
Publication statusPublished - 2005 Feb 18

Keywords

  • Cellular prion protein
  • Green fluorescent protein
  • Mitochondria-mediated apoptosis
  • PrP Y145STOP mutation
  • PrP-containing deposits

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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