Quantitative Proteomics of Secreted Proteins

Area of Science:

• Proteomics
• Cellular Biology
• Biochemistry

Background:

• Secreted proteins (cytokines, hormones, etc.) are crucial for intercellular communication.
• Conventional quantification relies on antibody-based methods (e.g., ELISA), which face limitations in scale, specificity, and cost.
• There is a need for high-throughput, cost-effective methods to quantify secreted proteins.

Purpose of the Study:

• To develop and validate a mass spectrometry-based workflow for comprehensive quantification of secreted proteins.
• To enable systems-level characterization of cellular secretory programs.
• To discover proteins with novel extracellular functions.

Main Methods:

• Collection of secreted proteins (in vitro or ex vivo).
• Proteolytic digestion of collected proteins into peptides.
• Analysis of peptide mixtures using single liquid chromatography-mass spectrometry (LC-MS/MS) runs.
• Label-free quantification and bioinformatics analysis using MaxQuant and Perseus software.

Main Results:

• Quantification of thousands of secreted proteins.
• Achieved quantification across a four-orders-of-magnitude concentration range.
• Enabled systems-level characterization of secretory pathways.
• Facilitated discovery of proteins with unexpected extracellular roles.

Conclusions:

• The developed mass spectrometry workflow offers a powerful, scalable alternative to traditional methods for secreted protein quantification.
• This approach provides deep insights into cellular secretory functions and facilitates the discovery of novel extracellular proteins.
• The workflow supports systems-level understanding of intercellular communication and protein function.