Volume 8 issue 4 April 2007
Fragmentation of the Golgi apparatus: an early apoptotic event independent of the cytoskeleton.
Shaeri Mukherjee, Raymond Chiu, Som-Ming Leung, and Dennis Shields

Figure 1: Comparison of the actin and tubulin cytoskeleton during staurosporine induced apoptosis. NRK cells were either untreated or treated with 1 µM staurosporine for 1hr after which they were prepared for immunofluorescence microscopy using the actin binding protein phalloidin (red) (panels A & D) and a monoclonal antibody to α-tubulin (green) (panels B & E); nuclei were stained with Hoechst stain (blue). Note the complete disruption of actin filaments at this time whereas microtubules were largely unaffected. Bar: 10 µm.

Figure 1 (jpg)

Figure 2: Actin and tubulin are cleaved during early stages of staurosporine induced apoptosis. NRK cells were either untreated or treated with 1 µM staurosporine for the indicated times and the cell lysates analyzed by western blotting using antibodies to full length and activated PARP, respectively, β-actin and α-tubulin.

Figure 2 (jpg)

Figure 3: Disruption of the actin cytoskeleton occurs prior to release of cytochrome C in response to staurosporine. NRK cells were treated with DMSO or staurosporine for 2 hr after which they were stained with the Mitotracker ® dye (red). Following fixation, the cells were stained with mouse monoclonal anti-cytochrome C (green) and actin binding protein phalloidin (blue). The nuclei were stained with Hoechst stain (purple).
Bar: 10 µm.

Figure 3 (jpg)

Figure 4: Inhibition of caspase activities abrogates Golgi fragmentation in response to staurosporine treatment. NRK cells were treated with either DMSO or pretreated with 0.1mM z-VAD-fmk for 2hr followed by 2hr treatment with staurosporine. Following fixation the cells were stained with the actin binding protein phalloidin (red) and mouse monoclonal anti-GM130 (green); nuclei were stained with Hoechst stain (blue). Bar: 10 µm.

Figure 4 (jpg)