Identification of candidate proteins binding to prion protein

Area of Science:

• Neuroscience
• Molecular Biology
• Biochemistry

Background:

• Prion diseases are neurodegenerative disorders caused by misfolded proteins.
• A factor, termed protein X, is implicated in the conversion of normal cellular prion protein (PrPC) to the pathogenic scrapie isoform (PrPSc).
• Protein X interacts with PrPC but not PrPSc, suggesting a specific binding interaction is key.

Purpose of the Study:

• To identify proteins that bind to the normal cellular prion protein (PrPC).
• To investigate potential interactions relevant to prion disease pathogenesis.
• To explore links between prion protein interactions and other neurodegenerative diseases, such as Alzheimer's.

Main Methods:

• A soluble, secreted probe was engineered by fusing PrPC with alkaline phosphatase (AP).
• This PrP-AP probe was utilized to screen a mouse brain cDNA library.
• Six cDNA clones were isolated, representing potential PrPC binding partners.

Main Results:

• Four novel cDNAs were identified.
• Two known cDNA fragments, Nrf2 (NF-E2 related factor 2) and Aplp1 (amyloid precursor-like protein 1), were also isolated.
• The binding of PrPC to a member of the amyloid precursor protein (APP) gene family was confirmed.
• Four of the isolated clones showed preferential expression in the mouse brain and shared a common motif.

Conclusions:

• The study successfully identified novel PrPC-binding proteins using a biochemical screening approach.
• The identification of Aplp1, a member of the APP family, suggests a potential link between prion diseases and Alzheimer's disease.
• These findings provide a foundation for further research into the molecular mechanisms underlying prion protein interactions and neurodegeneration.