Cocktail Chemical Labeling for In-Depth Surfaceome Profiling of Bone-Marrow-Derived Dendritic Cells

Cell surface proteins (CSPs) are crucial identifiers
for cell types
and states, especially in dendritic cells (DCs). Current proteomic
methods for profiling CSPs are limited by their hydrophobic nature
and low abundance, which often require genetic or cell surface engineering
and exhibit biased and insufficient labeling efficiency. Herein, we
report [Ru(bpy)3]Cl2 (Ru) for effective biotinylation
on the cell surfaceome via a simple “mix and lighten”
method. The versatile photoredox pathways of Ru are leveraged using
a probe cocktail of biotin-phenol and biotin-hydrazide for improved
substrate coverage. The “cocktail” labeling strategy
results in reproducible identification of up to 733 plasma membrane
proteins on HeLa cells and is further applied to map dynamic changes
in the surfaceome during the differentiation of primary bone-marrow-derived
dendritic cells, which demonstrates a user-friendly and deep-surfaceome-coverage
tool for profiling dynamic changes in primary cells, with potential
implications for cell identities, functional states, and novel drug
targets.