Intracellular localization of Bid-EYFP, tBid-EYFP and its deletion mutants.

CV-1 cells were transfected with plasmids encoding Bid-EYFP, tBid-EYFP or tBid-EYFP mutants in presence of 10 µM of Bok-D. 24 h later, cells were stained with 20 nM of the mitochondrial potential probe TMRE and the localization of the tBid-EYFP mutants was determined by calculation of the TMRE/EYFP ratios using microspectrofluorometry. A ratio of 1.0 indicates that EYFP exclusively colocalizes with TMRE at the mitochondria while a lower ratio indicates that EYFP is also localized to the cytosol. The * highlights the contructs that localize to the mitochondria but are unable to induce cytochrome c release or to alter mitochondrial bioenergetics. The constructs that localize to the cytoplasm are in italic.