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Monitoring Dynamic Changes In Mitochondrial Calcium Levels During Apoptosis Using A Genetically Encoded Calcium Sensor
Published on: April 1, 2011
Redox-dependent changes in molecular properties of mitochondrial apoptosis-inducing factor
Inna Y Churbanova1, Irina F Sevrioukova
1Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697-3900, USA.
The Journal of Biological Chemistry
|January 3, 2008
Summary
Mitochondrial apoptosis-inducing factor (AIF) acts as a redox-signaling molecule. Its interaction with NAD(P)H forms stable complexes, influencing cell death pathways.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Mitochondrial apoptosis-inducing factor (AIF) is implicated in caspase-independent cell death.
- The precise physiological role of AIF remains incompletely understood.
Purpose of the Study:
- To investigate the biochemical and functional properties of mouse AIF in relation to NAD(P)H.
- To elucidate the role of AIF in the regulation of caspase-independent apoptosis.
Main Methods:
- Enzyme kinetics assays to determine reaction rates between AIF and NAD(P)H.
- Spectroscopic methods to characterize the formation and properties of AIF-NAD(P)H complexes.
- Assessment of AIF's susceptibility to calpain and its interaction with DNA.
Main Results:
- Naturally folded mouse AIF exhibits slow reaction kinetics with NAD(P)H (kcat of 0.2-0.01 s(-1)).
- Formation of tight, dimeric, and air-stable FADH2-NAD(P) charge-transfer complexes that are ineffective in electron transfer.
- FAD reduction induces conformational changes affecting calpain susceptibility and AIF-DNA interaction, crucial for apoptosis initiation.
Conclusions:
- AIF forms long-lived complexes with NAD(P)H, suggesting a role beyond simple electron transfer.
- Redox reorganization involving AIF may position it as a redox-signaling molecule.
- AIF links NAD(P)H-dependent metabolic pathways to the initiation of apoptosis.
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