Related Experiment Videos
ATP-dependent steps in apoptotic signal transduction
Y Eguchi1, A Srinivasan, K J Tomaselli
1Department of Medical Genetics, Biomedical Research Center, Osaka University Medical School, Suita, Japan.
Cancer Research
|May 8, 1999
Summary
Adenosine triphosphate (ATP) levels are critical for Fas-mediated apoptosis. This study reveals distinct ATP-dependent steps in type I and type II cells, impacting caspase activation and nuclear changes during apoptosis.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- Fas (Apo1/CD95) stimulation triggers nuclear apoptotic changes.
- Intracellular adenosine triphosphate (ATP) levels are essential for these nuclear events.
- Understanding the ATP-dependent steps in Fas-mediated apoptosis is crucial.
Purpose of the Study:
- To investigate the ATP-dependent steps in Fas-mediated apoptotic signal transduction.
- To compare these ATP-dependent mechanisms in type I (SKW6.4) and type II (Jurkat) cells.
Main Methods:
- Utilized two cell lines (SKW6.4 and Jurkat) to study Fas-mediated apoptosis.
- Manipulated intracellular ATP levels to assess their impact on apoptotic signaling pathways.
- Monitored caspase activation (caspases 8, 9, and 3), cytochrome c release, DFF45 (ICAD) cleavage, and nuclear fragmentation.
Main Results:
- In type I cells, ATP reduction inhibited nuclear changes but not caspase activation or cytochrome c release.
- In type II cells, ATP reduction blocked caspase activation and nuclear changes, but not cytochrome c release.
- Identified distinct ATP-dependent steps downstream of caspase 3 in type I cells and upstream of caspase 9 activation in type II cells.
Conclusions:
- Fas-mediated apoptosis involves at least two distinct signaling pathways.
- Type I cells have ATP-dependent steps only after caspase 3 activation.
- Type II cells rely on ATP for caspase 9 activation, indicating the Apaf-1 system's ATP dependence in vivo.