FIGURE 4.

Loss of mitochondrial transmembrane potential and induction of caspase cleavage by co-expression of KLB and FGFR4. A, mitochondrial membrane potential. Uptake and retention of the cationic voltage-sensitive lipophilic dye Rhodamine 123 in 293 cells expressing the indicated combinations of KLB and FGFR4 and treated with Tet and FGF19 were assessed by flow cytometry. B, cleavage of caspase 3. The lysates from 293 cells co-expressing KLB and FGFR4 after treatment with Tet and FGF19 were separated by SDS-PAGE, and the cleavage of caspase 3 into active fragments was then assessed by immunoblot analysis. The levels of FGFR4 and KLB were shown by immunoblotting of whole cell lysates as in Fig. 2.