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Confocal Imaging of Single Mitochondrial Superoxide Flashes in Intact Heart or In Vivo
Published on: November 5, 2013
OPA1 promotes pH flashes that spread between contiguous mitochondria without matrix protein exchange.
Jaime Santo-Domingo1, Marta Giacomello, Damon Poburko
1Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland.
The EMBO Journal
|May 30, 2013
Summary
Mitochondrial flashes are matrix alkalinization events that help equilibrate energy between connected mitochondria. These flashes, linked to membrane potential changes, occur without matrix content exchange and are regulated by fusion and fission proteins.
Area of Science:
- Mitochondrial biology
- Cellular energetics
- Membrane dynamics
Background:
- The nature and role of mitochondrial flashes, linked to membrane potential fluctuations, remain poorly understood.
- Mitochondrial flashes are transient events affecting mitochondrial membrane potential.
Purpose of the Study:
- To elucidate the chemical basis and functional significance of mitochondrial flashes.
- To investigate the role of mitochondrial dynamics proteins in flash propagation.
Main Methods:
- Utilized a ratiometric pH probe to detect matrix alkalinization.
- Employed Optic atrophy 1 (pro-fusion) and Dynamin-related protein 1 (pro-fission) knockouts.
- Assessed propagation of matrix photoactivated GFP (paGFP) to monitor matrix diffusion.
Main Results:
- Mitochondrial flashes correspond to matrix alkalinization transients (∼0.4 pH units).
- Optic atrophy 1 ablation abolished flashes; Dynamin-related protein 1 ablation enhanced flash propagation.
- Flashes propagate between mitochondria without matrix content exchange, promoting membrane potential equilibration.
Conclusions:
- Mitochondrial flashes are energy conservation events triggered by fusion pores between mitochondria with differing membrane potentials.
- These flashes facilitate energetic state equilibration in connected mitochondria without complete fusion.
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