Identification of apoptosis modulators. Shown are plots of the fluorescence intensity in the YFP channel (expression of the recombinant proteins) against the level of activated caspase-3 (measured with an APC-labeled antibody). NIH3T3 cells were transfected with ORFs that were C- or N-terminally tagged with YFP. After 24 h, the cells were stained with an antibody directed against the active form of caspase-3 and measured by FACS. For every protein, the percentage of transfected cells (YFP > 10e1) that were positive for activated caspase-3 (APC > 10e1) is given as compared with the transfected cells (YFP > 10e1) that were negative in active caspase-3 (APC < 10e1). APC is fluorescence of the secondary antibody labeled with allophycocyanine. FAS (Chinnaiyan et al. 1995) is the receptor for the cytokine ligand known as FASL. Activated Fas results in the formation of Death-inducing signaling complex, which ultimately leads to cell death (activator control). Bcl-2 (Hockenbery et al. 1990) is an integral protein of the inner mitochondrial membrane that blocks apoptotic death (inhibitor control). YFP is the YFP protein. P097 is the DKFZp434P097 protein. All proteins were expressed as fusion proteins with YFP.
