A proximity labeling method for protein-protein interactions on cell membrane

Area of Science:

• Biochemistry
• Proteomics
• Molecular Biology

Background:

• Antibodies are crucial tools in biological research for target identification and quantification.
• Mapping protein interactions and specific modification sites is essential for understanding cellular mechanisms.

Purpose of the Study:

• To introduce and validate antigen-antibody proximity labeling (AAPL), a novel technique for mapping antibody-bound protein interactions and oxidation sites.
• To demonstrate the utility of AAPL in identifying antigen interaction sites and proximal proteins.

Main Methods:

• Antibodies were modified with an Fe(iii) catalytic probe.
• Fe(iii)-induced oxidation was performed upon antibody binding to target antigens.
• Oxidative proteomic analysis was employed to identify oxidation sites and proximal proteins.
• An AAPL score was developed to quantify oxidation specificity and protein proximity.

Main Results:

• AAPL successfully mapped oxidation sites on target antigens like ATP1A1 and ERBB2.
• The method identified proteins in close proximity to the targeted antigens.
• AAPL was applied to map interactors of liver-intestine-cadherin (CDH17) in colon cancer cells.

Conclusions:

• Antigen-antibody proximity labeling (AAPL) is a powerful new method for mapping protein interaction sites and proximal proteins.
• AAPL provides insights into antibody-antigen interactions and protein complex organization.
• This technique has broad applications in biological research and disease studies, including cancer research.