Figure 1
Principle of the comparative imaging approach (CosiQuant). Biochemically characterized synaptosome preparations are immobilized on coverslips. Cultured hippocampal neurons are immunostained in parallel with the synaptosomes for the synaptic vesicle marker synaptophysin (green), the active zone marker bassoon (blue) and the protein of interest (orange). The insets show example images of the fluorescently labeled structures (synapses/synaptosomes). Fluorescent signals for all labeled proteins are acquired, and intensities are compared between the synaptosome and neuron samples. Finally, protein copy numbers in cultured neuronal synapses can be estimated by comparing the intensities. Scale bar in overview images = 25 µm; scale bar in insets = 2 µm.
