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Updated: May 31, 2026

In Situ Monitoring of Transiently Formed Molecular Chaperone Assemblies in Bacteria, Yeast, and Human Cells
Published on: September 2, 2019
H2O2-free proximity proteomics for exploring dynamic protein complexes in living systems
Mi Ke1, Fuchao Liang1, Guangqin Wang2
1State Key Laboratory of Medical Proteomics and Shenzhen Key Laboratory of Functional Proteomics, Department of Chemistry and Research Center for Chemical Biology and Omics Analysis, College of Science and Guangming Advanced Research Institute, Southern University of Science and Technology, Shenzhen, China.
Abstract:
Dynamic protein complex assembly is critical for regulating various biological processes. Proximity labeling (PL), best represented by the ascorbate peroxidase APEX2, allows these molecular events to be captured in living cells in a spatiotemporal manner. However, the hydrogen peroxide (H2O2) dependence of APEX2 has hindered its application in sensitive living systems. Here we introduce ROProx, a radical- and oxygen-driven photoreactive PL technology that leverages the chemically evolved biotin-naphthylamine probe BN2, which has strong binding affinity for APEX2, and the unexpected tyrosyl radicals in APEX2. ROProx labels dynamic cytosolic protein complexes in living cells within seconds, with a range of 10 nm, and is precisely controlled by mild blue light irradiation without H2O2. Additionally, we apply ROProx to explore the phosphotyrosine-dependent GRB2 interactome in living mice by simply injecting BN2 for 5 minutes. ROProx should, therefore, open broad opportunities for PL chemical evolution and applications in other living systems.
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