A Schematic presentation of the approach. Cytosolic translation is inhibited with Harringtonine (Harr) while mitochondrial ribosomes are allowed to incorporate the alkyne-containing methionine homolog (HPG, orange) into newly-synthesized proteins. In fixed cells, HPG moieties are clicked to an azide-conjugated fluorophore (star, magenta), through copper-catalyzed Huisgen cycloaddition (click), and can be visualized microscopically. 