HeLa cells were co-transfected with Ub-R-GFP and Myc or F1-Myc and immunostained with fluorescent anti-Myc and anti-GFP (α-GFP) antibodies. The α-GFP signals in F1-Myc transfected cells were lowered to avoid the overexposure of the mitochondrially localized R-GFP, making such signals of the equally distributed R-GFP invisible. Green arrowheads show the mitochondrially localized R-GFP proteins, which were more abundant than the equally distributed R-GFP and showed stronger R-GFP fluorescence, white arrowheads show the mitochondrially localized R-GFP proteins without stronger R-GFP fluorescence, although abundant. Scale bar=10 µm. 