Mutations Outside the Ure2 Amyloid-Forming Region Disrupt [URE3] Prion Propagation and Alter Interactions with...

Area of Science:

• Molecular biology
• Yeast genetics
• Prion biology

Background:

• Yeast prions, like [URE3] formed by Ure2 protein, propagate as amyloids.
• Protein quality control (PQC) factors are essential for prion propagation and can be targeted for prion curing.
• The precise interactions between PQC factors and prion proteins are not fully understood.

Purpose of the Study:

• To investigate how mutations outside the Ure2 prion-determining region affect [URE3] prion stability and propagation.
• To explore the role of non-amyloid forming regions of Ure2 in interactions with protein quality control factors.

Main Methods:

• Generated and characterized mutations in the Ure2 protein outside its prion-forming region.
• Assessed the impact of mutations on [URE3] prion loss, propagation, and sensitivity to PQC factors (Btn2, Cur1, Hsp42).
• Evaluated in vitro amyloid formation and prion replication/transmission for specific mutants.

Main Results:

• Most Ure2 mutants outside the prion region retained protein activity.
• Four mutants rapidly lost [URE3] but could re-propagate it under selective conditions.
• Mutations differentially affected sensitivity to specific PQC factors and in vitro amyloid formation, impacting prion replication or transmission.

Conclusions:

• Dispersed sites outside the amyloid-forming region of Ure2 significantly influence prion character.
• Modifying these sites can disrupt prion propagation by altering interactions with PQC systems.
• This highlights potential new therapeutic targets for prion diseases by modulating protein interactions.