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Monitoring Dynamic Changes In Mitochondrial Calcium Levels During Apoptosis Using A Genetically Encoded Calcium Sensor
Published on: April 1, 2011
Oxidative modification sensitizes mitochondrial apoptosis-inducing factor to calpain-mediated processing.
Erik Norberg1, Vladimir Gogvadze, Helin Vakifahmetoglu
1Institute of Environmental Medicine, Division of Toxicology, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
Free Radical Biology & Medicine
|January 2, 2010
Summary
Reactive oxygen species (ROS) and calcium elevation trigger apoptosis-inducing factor (AIF) cleavage by calpain. ROS-mediated AIF carbonylation enhances its processing, crucial for AIF-mediated cell death.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- Mitochondrial apoptosis-inducing factor (AIF) processing is vital for apoptosis but its cleavage mechanisms are unclear.
- Previous studies suggest Ca(2+) dependence and calpain mediation for AIF cleavage.
Purpose of the Study:
- To elucidate the detailed mechanisms of AIF cleavage and release from mitochondria.
- To investigate the role of reactive oxygen species (ROS) and calcium in AIF processing.
Main Methods:
- Utilized staurosporine-treated cells to induce apoptosis.
- Measured intracellular Ca(2+) and ROS levels.
- Assessed AIF cleavage, release, and carbonylation.
- Employed BAPTA/AM for Ca(2+) chelation and antioxidants to inhibit ROS.
Main Results:
- Sustained intracellular Ca(2+) elevation and enhanced ROS formation are prerequisites for AIF cleavage and release.
- Ca(2+) rise acts as an upstream signal, triggering ROS production.
- ROS stimulates AIF carbonylation, increasing its susceptibility to calpain cleavage.
- Antioxidant treatment prevents AIF carbonylation, cleavage, and mitochondrial release.
Conclusions:
- ROS-mediated posttranslational modification (carbonylation) of AIF is critical for its calpain-dependent cleavage.
- This pathway is essential for AIF-mediated cell death during apoptosis.
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