Profiling of the Golgi Apparatus Proteome in Living Cells Using Nanophotosensitizer-Mediated Photocatalytic Proximity Labeling

Eukaryotic cells are characterized by a high degree of
compartmentalization,
wherein the function of proteins is intricately tied to their subcellular
localization, as distinct compartments provide specialized microenvironments.
The Golgi apparatus serves as a critical hub for the processing and
sorting of proteins within intracellular trafficking pathways. The
identification of the Golgi apparatus proteome in living cells is
of great significance for understanding both intercellular and intracellular
communication networks. However, this still poses a significant challenge
because of the scarcity of targeted labeling strategies, which is
attributed to the fact that the stacked structure of the Golgi apparatus
membrane hinders the access of traditional organic molecule photosensitizers.
Inspired by the mechanism of chondroitin sulfate accumulation in the
Golgi apparatus of living cells, we prepared the Golgi apparatus-targeting
nanophotosensitizer by combination of chondroitin sulfate and photosensitizers.
The nanophotosensitizer enabled photocatalytic proximity labeling
of the Golgi apparatus proteome with high spatiotemporal precision
under native conditions. After validation in living HeLa cells, which
demonstrated that more than 400 Golgi apparatus-annotated proteins
were identified, we applied the strategy to dynamic Golgi apparatus
proteome mapping of brain metastatic lung cancer cells. We found that
Golgi apparatus proteins played a role in signal transduction and
extracellular matrix organization during cancer metastasis. Overall,
this study not only significantly advanced the identification of the
Golgi apparatus proteome but also provided new insights into the potential
functions of the Golgi apparatus.