Microscopy-guided proteomics

Jung-Chi Liao^1*

¹Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan

* Presenter:Jung-Chi Liao, email:jcliao@iams.sinica.edu.tw

Subcellular spatial proteomic profiling is essential for understanding underlying molecular mechanisms of cell activities and diseases. Previously, enzyme-catalyzed proximity labeling and immunoprecipitation followed by mass spectrometry were popular solutions. However, lack of flexibility on choosing region of interest (ROI) largely reduces its applicability on broad cell biology problems. Here, we introduce a powerful tool allowing microscopy-guided, spatially resolved proteomics through an integration of optical microscopy and chemical labeling. A hybrid platform of epifluorescence and multiphoton microscopy was built for simultaneous fluorescence imaging, ROI assigning and photochemical desthiobiotinylation at submicron resolution in three dimensions. Desthiobiotinylated proteome were enriched and identified by the LC-MS/MS. We made an initial demonstration on proteome mapping of human cellular nucleus with high specificity. Our results show that this new approach of microscopy-guided subcellular proteomic mapping will broadly benefit the cell biology field in revealing novel and significant protein-protein interactions.

Keywords: multiphoton microscopy, proteomics, photochemistry