YFP-Parkin (green) does not translocate to mitochondria (red) when HeLa cells are transfected with PARL (presenilin-associated rhomboid-like protein) siRNA. HeLa cells stably expressing YFP-Parkin were transfected with PARL siRNA for 192 hours, treated with DMSO for 1 hour and then stained with TMRE, a cationic fluorescent dye that is readily sequestered by active mitochondria. Cells were imaged using an inverted microscope (LSM510 Meta; Carl Zeiss, Inc.) with a 63× 1.4 NA oil differential interference contrast Plan Apo objective. Image contrast and brightness were adjusted in the accompanying image browser (LSM; Carl Zeiss, Inc.). Image corresponds to Fig1f, bottom panels in J Cell Biol. 191: 933-942, 2010. Images in Fig1f include CIL#s 13707, 13708, 13709.