Requirements for mutant and wild-type prion protein misfolding in vitro

Area of Science:

• Biochemistry
• Neuroscience
• Molecular Biology

Background:

• Prion protein (PrP) misfolding is central to prion disease pathogenesis.
• Understanding PrP misfolding mechanisms is crucial for developing therapeutic strategies.

Purpose of the Study:

• To investigate the in vitro misfolding of the pathogenic PrP mutant D177N using a chemically defined system.
• To elucidate the factors influencing spontaneous PrP misfolding and templating.

Main Methods:

• Utilized a chemically defined prion propagation system.
• Studied the D177N PrP mutant's spontaneous misfolding kinetics.
• Assessed the templating ability of misfolded mutant PrP onto wild-type PrP.
• Investigated the role of phospholipids and cofactor molecules.

Main Results:

• The D177N PrP mutant misfolded spontaneously, influenced by time, temperature, pH, and sonication.
• Spontaneously misfolded mutant PrP templated its conformation onto wild-type PrP via a distinct phospholipid activity.
• Pathogenic mutant E199K showed similar behavior, while M128V did not.
• Wild-type PrP inhibited mutant PrP misfolding, an effect antagonized by cofactors.

Conclusions:

• PrP misfolding in inherited prion diseases is controlled by interactions between mutant PrP, wild-type PrP, and cellular factors.
• Distinct mechanisms govern spontaneous mutant PrP misfolding and templating compared to infectious prion propagation.