Immunoblot comparing the cytosolic supernatant and the mitochondria-enriched pellet of isolation fractions. GFP-tagged mtON migrates at the predicted molecular weight of 82 kDa accounting for the mitochondria-target sequence, the proton pump, and GFP. mtON is observed only in the mitochondrial fraction compared to marker proteins HSP60 (mitochondria) and actin (cytosol). All blots are from the same lanes on one membrane. 