The three faces of Sup35.

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Sup35p is crucial for yeast translation termination, working with Sup45p.
• Beyond termination, Sup35p has roles in stress response and prion formation.
• The N-terminal and middle (NM) regions of Sup35p are key to these additional functions.

Purpose of the Study:

• To review the three distinct functional states of Sup35p.
• To compare domain requirements and protein interactions for each state.
• To discuss the adaptive significance of Sup35p's varied roles in yeast.

Main Methods:

• Literature review and comparative analysis of Sup35p functions.
• Examination of domain necessity for translation termination, stress response, and prion formation.
• Analysis of protein-protein interactions and biomolecular condensate formation.

Main Results:

• Sup35p's NM domain mediates stress-sensing and phase separation into condensates.
• The NM domain is also essential for Sup35p misfolding and [PSI+] prion aggregation.
• Each functional state involves distinct domain contributions and protein partnerships.

Conclusions:

• Sup35p exhibits multifaceted roles beyond translation termination.
• These functions, including stress adaptation and prion biology, are critical for yeast survival.
• Understanding Sup35p's diverse "faces" provides insight into cellular resilience.