Integrated Proteogenomic Approach for Identifying Degradation Motifs in Eukaryotic Cells

Area of Science:

• Cellular Biology
• Molecular Biology
• Proteomics

Background:

• The ubiquitin-proteasome system (UPS) is crucial for protein degradation, but the signals initiating substrate interaction remain largely unknown.
• Cellular protein quality control (PQC) mechanisms target misfolded proteins, yet only a few ubiquitination pathways are characterized for this process.
• Understanding how specific PQC ubiquitin-protein ligases recognize diverse misfolded proteins is a significant challenge.

Purpose of the Study:

• To elucidate the recognition signals that initiate substrate interaction with the UPS machinery.
• To understand the mechanism of substrate recognition for non-native proteins within the PQC defense system.
• To identify and characterize recognition motifs within degradation elements (degrons) in a high-throughput manner.

Main Methods:

• Developed a novel proteogenomic approach for high-throughput identification and characterization of degrons.
• Utilized yeast growth under restrictive conditions to select protein fragments conferring instability.
• Employed next-generation sequencing (NGS) to analyze cDNA fragments, determining identity, reading frame, and abundance over time.

Main Results:

• Successfully identified PQC-specific and compartment-specific degrons using the new proteogenomic method.
• The NGS analysis provided comprehensive data on fragment characteristics and their dynamic changes.
• Demonstrated the method's efficacy in uncovering degradation signals for misfolded proteins.

Conclusions:

• The developed proteogenomic approach enables efficient identification and characterization of protein degradation signals (degrons).
• This method advances the understanding of substrate recognition by PQC ubiquitin-protein ligases.
• The approach is adaptable for studying protein degradation pathways in various organisms and conditions.