Abnormalities in stress proteins in prion diseases

Area of Science:

• Neurodegenerative diseases
• Protein misfolding disorders
• Molecular biology

Background:

• Prion diseases, including CJD and BSE, are characterized by the conversion of normal cellular prion protein (PrPC) into an abnormal, protease-resistant isoform (PrPSc).
• This conversion involves a significant conformational change, indicating that prion diseases are fundamentally disorders of protein conformation.
• Heat shock proteins (Hsp) are known molecular chaperones involved in protein folding and homeostasis.

Purpose of the Study:

• To investigate the potential role of heat shock proteins (Hsp) in the pathogenesis of prion diseases.
• To examine alterations in Hsp induction and distribution within cells infected with prions.

Main Methods:

• Studied scrapie-infected cells to analyze the expression patterns of various heat shock proteins (Hsp).
• Investigated the cellular distribution of Hsp73 in scrapie-infected cells.
• Compared Hsp induction in normal versus prion-infected cellular models.

Main Results:

• Observed profound alterations in the induction of specific Hsps in scrapie-infected cells.
• Found an unusual cellular distribution pattern for Hsp73 in these infected cells.
• Demonstrated differential effects on Hsp induction, with some Hsps affected and others not.

Conclusions:

• The findings suggest a potential involvement of molecular chaperones, specifically heat shock proteins, in the conversion of PrPC to PrPSc or in the subsequent handling of misfolded PrPSc.
• Further research is needed to elucidate whether molecular chaperones actively assist in PrPC to PrPSc conversion or if they associate with the accumulated abnormal PrPSc.
• Prion diseases may represent a complex interplay between protein conformational changes and cellular chaperone machinery.