Fig. 2.

Mitochondrial membrane proteins atypically expressed in the cytoplasm localize to the ER. Amino acid sequences of COX1, ATP6, and CYB were reverse-translated to nuclear codon use and FLAG-tagged at their amino termini. HeLa cells were transfected with plasmids containing these synthetic genes and subjected to immunofluorescence analysis. From the top, FLAG-tagged ERLIN1 and OMP25-GFP constructs were used as positive localization controls and immunostained with antibodies marking the ER (calnexin) or mitochondria (TOM20). Below this, localization analyses of the synthetic mitochondrial membrane proteins COX1, ATP6, and CYB. (Scale bars, 5 µm.)