Development and validation of a method for profiling post-translational modification activities using protein...

Area of Science:

• Biochemistry
• Molecular Biology
• Proteomics

Background:

• Post-translational modifications (PTMs) are crucial for protein function and cellular diversity.
• Analyzing PTMs proteome-wide is essential for understanding signaling networks but technically challenging.
• Current methods for large-scale PTM evaluation are limited.

Purpose of the Study:

• To develop a protein microarray-based assay for profiling PTM activities.
• To facilitate the analysis of PTMs in complex biological mixtures like cell extracts and pathological specimens.
• To enable proteome-wide studies of PTMs and their role in biological processes.

Main Methods:

• Utilized protein microarrays as a substrate for in vitro enzymatic reactions.
• Applied labeled modifiers (ubiquitin, SUMO1, NEDD8) and ATP regenerating systems.
• Profiled ubiquitylation, SUMOylation, and NEDDylation using purified ligases and cell/pathological extracts.
• Validated novel PTM substrates identified through the assay by confirming in vivo modification.

Main Results:

• Successfully profiled three complex PTMs: ubiquitylation, SUMOylation, and NEDDylation.
• Demonstrated the assay's capability with both purified enzymes and complex biological extracts.
• Identified novel PTM substrates, which were further validated in vivo.
• The assay proved effective across various sample types, including pathological specimens.

Conclusions:

• The developed protein microarray assay offers advantages in ease of use, speed, scalability, and sample diversity.
• This methodology allows direct comparison of enzymatic activities in different cell populations or pathological states.
• Has broad applications for studying PTMs in human diseases and fundamental PTM research.