Assessing Multiple Evidence Streams to Decide on Confidence for Identification of Post-Translational Modifications,...

Area of Science:

• Proteomics
• Molecular Biology
• Biochemistry

Background:

• Phosphorylation is a critical post-translational modification involved in numerous biological processes.
• High-throughput LC-MS/MS techniques identify thousands of phosphosites, but analytical pipelines introduce uncertainty.
• Global false localization rates in phosphosite identification are often unknown due to arbitrary thresholding.

Purpose of the Study:

• To develop a robust pipeline for accurate phosphosite identification and localization.
• To objectively collapse data from peptide-spectrum matches to the peptidoform-site level.
• To combine findings from multiple studies while rigorously tracking false localization rates.

Main Methods:

• Utilized decoy amino acids to estimate global false localization rates.
• Developed a pipeline for objective data collapsing and multi-study integration.
• Applied the pipeline to rice phosphoproteomics datasets.

Main Results:

• The decoy approach identified 6368 unique phosphosites in rice datasets.
• Traditional thresholding methods identified only 4687 unique sites.
• The new pipeline demonstrated superior effectiveness in handling phosphosite identification redundancy.

Conclusions:

• The developed pipeline provides a more effective method for phosphosite identification and localization.
• Tracking false localization rates using decoy approaches enhances data reliability.
• This method maximizes information extraction from phosphoproteomics studies.