Fig. 1

Dopamine probe (DA-P) serves as an effective chemical tool for protein labeling in MN9D cells. A Schematic illustration of the synthesis route for DA-P. Structures of DA and DA-P are shown. B Trypan blue exclusion test of MN9D cell viability following treatment with different concentrations of DA or DA-P (0, 100, 200, 400 and 800 μM) for 24 h. C In-gel fluorescence visualization of proteins labeled by indicated concentrations of DA-P for 3 h in live MN9D cells through the copper-catalyzed azide–alkyne cycloaddition reaction (CuAAC). D In-gel fluorescence visualization of MN9D proteome after pre-treatment with indicated concentrations of DA for 4 h followed by 100 μM DA-P labeling. E Representative fluorescence images of MN9D cells following treatment with 0 μM, 50 μM, 100 μM or 200 μM of DA-P, respectively for 3 h. Cells were processed for CuAAC click reaction with TAMRA-azide. Error bars, mean ± SEM. Scale bar, 10 μm. Fluo fluorescence, CBB coomassie brilliant blue