Site-Specific Proteomic Mapping Identifies Selectively Modified Regulatory Cysteine Residues in Functionally Distinct...

Area of Science:

• Biochemistry
• Proteomics
• Cellular Signaling

Background:

• Cysteine modifications like S-acylation, S-glutathionylation, S-nitrosylation, and S-sulfenylation are crucial for protein function and redox sensing.
• The integration and biological significance of these modifications across the proteome remain largely unexplored.

Purpose of the Study:

• To investigate the global landscape of cysteine modifications in mouse liver proteome under physiological conditions.
• To identify protein networks involved in endogenous redox signaling through specific cysteine modifications.

Main Methods:

• Utilized novel mass spectrometry-based technologies to identify and quantify cysteine modification sites.
• Performed structural analysis to localize modifications and quantitative proteomics to assess cross-talk between different modifications.

Main Results:

• Identified 2,596 unique modification sites in 1,319 mouse liver proteins.
• Localized modifications to conserved protein segments, often outside known functional regions.
• Demonstrated fine-tuned in vivo reactivity and specificity, with no direct correlation between S-nitrosylation and S-glutathionylation levels.
• Uncovered clustering of modifications within biologically related protein networks.

Conclusions:

• Provides the first comprehensive evidence for distinct endogenous protein networks regulated by specific cysteine modifications.
• These networks play a significant role in cellular redox signaling pathways.