Figure 4.
Loss of OPA1 isoforms corresponds to the induction of BI97C1-, BI112D1-, and ABT-263-mediated mitochondrial fragmentation. (A) H23 cells, reverse transfected with siRNA against OPA1 or MFN1 for 72 hours followed by immunostaining with HSP60, reveal a fragmented mitochondrial network (scale bar, 10 µm). (B) Western blots showing the knockdown efficiency of different siRNA oligoduplexes. (C) H23 cells exposed to 10 µM ABT-263, BI97C1, or BI112D1 for the indicated times and probed for different mitochondrial fusion proteins reveal a time-dependent loss of the high molecular weight isoforms of OPA1. (D) Quantification of the percentage of cells exhibiting normal mitochondrial structure after exposure to 10 µM ABT-263, BI97C1, or BI112D1 in H23 cells for the indicated times reveals the kinetics of extensive mitochondrial fragmentation and the loss in mitochondrial membrane potential (ψm).