Ubiquitin precursor with C-terminal extension promotes proteostasis and longevity

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Biology

Background:

• Ubiquitin (Ub) is a key protein modifier regulating protein stability and function.
• Ubiquitin precursors are processed into monomers, typically with a C-terminal extension of unknown significance.

Purpose of the Study:

• To investigate the physiological role of C-terminally extended ubiquitin (CxUb).
• To elucidate the mechanism by which CxUb influences cellular processes.

Main Methods:

• Utilized Saccharomyces cerevisiae and Caenorhabditis elegans models.
• Investigated CxUb's role in stress resistance, mitophagy, and longevity.
• Analyzed the interaction between CxUb and the Ufd2 enzyme.

Main Results:

• CxUb is essential for stress resistance, mitophagy, and longevity in yeast and worms.
• CxUb forms ubiquitin chains and interacts with a novel region of the Ufd2 enzyme.
• Ufd2 utilizes CxUb to target specific substrates for degradation during stress and aging.

Conclusions:

• CxUb represents a functionally unique ubiquitin form specialized for proteostasis.
• CxUb plays a critical role in stress response and aging pathways.
• This discovery expands the understanding of post-translational modification processes.