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Investigating the Spreading and Toxicity of Prion-like Proteins Using the Metazoan Model Organism C. elegans
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Investigating the Spreading and Toxicity of Prion-like Proteins Using the Metazoan Model Organism C. elegans

Published on: January 8, 2015

A mutant prion protein displays an aberrant membrane association when expressed in cultured cells

S Lehmann1, D A Harris

  • 1Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.

The Journal of Biological Chemistry
|October 13, 1995
PubMed

Insights

Mutant prion protein (PrP) in inherited prion diseases shows altered membrane attachment. Even after GPI anchor cleavage, the mutant PrP remains cell-surface bound, suggesting novel interactions in prion disease pathogenesis.

Area of Science:

  • Neuroscience
  • Molecular Biology
  • Genetics

Background:

  • Inherited prion diseases are linked to mutations in the prion protein (PrP) gene.
  • PrP is a cell surface protein attached via a glycosyl-phosphatidylinositol (GPI) anchor.
  • A specific mutation involves extra octapeptide repeats, associated with familial Creutzfeldt-Jakob disease.

Purpose of the Study:

  • To analyze the membrane attachment of a mutant murine PrP homologue in cultured cells.
  • To investigate if the mutant PrP exhibits altered membrane association compared to wild-type PrP.

Main Methods:

  • Cultured Chinese hamster ovary (CHO) cells expressing wild-type and mutant murine PrP.
  • Analysis of PrP glycosylation, GPI anchoring, and cell surface expression.
  • Treatment with phosphatidylinositol-specific phospholipase C (PI-PLC) to cleave the GPI anchor.
  • Hydrophobicity and membrane association assays using Triton X-114 and carbonate buffer.

Main Results:

  • The mutant PrP is glycosylated, GPI-anchored, and expressed on the cell surface, similar to wild-type PrP.
  • Cleavage of the GPI anchor by PI-PLC did not release the mutant PrP from intact cells.
  • The phospholipase-treated mutant PrP demonstrated hydrophobic properties and tight membrane association.

Conclusions:

  • Mutant PrP exhibits an additional, non-GPI-mediated mode of membrane attachment.
  • This altered membrane association may involve polypeptide integration, self-association, or binding to other membrane proteins.
  • Changes in PrP membrane association are potentially significant in the development of prion diseases.

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