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dATP causes specific release of cytochrome C from mitochondria
1Department of Molecular Biosciences, University of California, Davis 95616, USA.
Biochemical and Biophysical Research Communications
|October 1, 1998
Summary
Deoxadenosine triphosphate (dATP) directly triggers cytochrome c release from mitochondria independently of swelling. This mechanism explains dATP toxicity in certain genetic immunodeficiency diseases.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Toxicology
Background:
- Mitochondrial Permeability Transition (MPT) is linked to cytochrome c release, a key event in apoptosis.
- Cytochrome c release can occur via swelling-dependent or swelling-independent pathways.
Purpose of the Study:
- To investigate the mechanism of cytochrome c release induced by canonical MPT inducers and deoxadenosine triphosphate (dATP).
- To determine if dATP induces cytochrome c release through a swelling-dependent or independent pathway.
Main Methods:
- Mitochondrial swelling and protein release assays.
- Osmotic support experiments using PEG-1000.
- Inhibition studies with cyclosporin A and z-VAD.
Main Results:
- Canonical MPT inducers (Ca2+, t-butyl hydroperoxide, atractyloside) caused swelling-dependent cytochrome c release.
- dATP induced cytochrome c release independently of mitochondrial swelling, even with osmotic support.
- dATP-induced release was inhibited by cyclosporin A but not by the caspase inhibitor z-VAD.
Conclusions:
- dATP directly induces cytochrome c release from mitochondria in a swelling-independent manner.
- This pathway is distinct from canonical MPT induction and caspase activation.
- The findings provide a molecular explanation for dATP toxicity in Adenosine Deaminase deficiency and Purine Nucleotide Phosphorylase deficiency.