Figure 5

Signal transduction cascades regulate the mitochondrial fusion reaction. (a) HeLa cells were either untreated (left panels), treated with 10 μM forskolin for 30 min or with 1.5 μM staurosporin for 4 h were fixed and stained with anti-prdx3 antibodies to label mitochondria. Bottom panels show a 3× magnification of the boxed areas. Scale bars are 10 μ. (b) Renilla luciferase complementation is shown for mitochondrial fusion reactions containing 5 mg/mL sHeLa cytosol, or cytosols treated with forskolin or staurosporin, as indicated. The addition of 10 μM forskolin directly to the fusion reaction does not have any effect. Apyrase and 4°C controls are also shown. (b) As in b, including a control where HeLa cells were incubated with 10 μM forskolin for 30 min in the presence of its inhibitor H89 (10 μM, 1 h pre-incubation) prior to harvesting the cytosol for addition into the cell free assay.