Poburko 2011 J Biol Chem: Difference between revisions
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Latest revision as of 17:53, 16 January 2021
Poburko Damon, Santo-Domingo Jaime, Demaurex Nicolas (2011) Dynamic regulation of the mitochondrial proton gradient during cytosolic calcium elevations. J Biol Chem 286:11672-84. |
ยป Open Access
Poburko Damon, Santo-Domingo Jaime, Demaurex Nicolas (2011) J Biol Chem
Abstract: Mitochondria extrude protons across their inner membrane to generate the mitochondrial membrane potential (ฮฮจ(m)) and pH gradient (ฮpH(m)) that both power ATP synthesis. Mitochondrial uptake and efflux of many ions and metabolites are driven exclusively by ฮpH(m), whose in situ regulation is poorly characterized. Here, we report the first dynamic measurements of ฮpH(m) in living cells, using a mitochondrially targeted, pH-sensitive YFP (SypHer) combined with a cytosolic pH indicator (5-(and 6)-carboxy-SNARF-1). The resting matrix pH (โผ7.6) and ฮpH(m) (โผ0.45) of HeLa cells at 37 ยฐC were lower than previously reported. Unexpectedly, mitochondrial pH and ฮpH(m) decreased during cytosolic Ca(2+) elevations. The drop in matrix pH was due to cytosolic acid generated by plasma membrane Ca(2+)-ATPases and transmitted to mitochondria by P(i)/H(+) symport and K(+)/H(+) exchange, whereas the decrease in ฮpH(m) reflected the low H(+)-buffering power of mitochondria (โผ5 mm, pH 7.8) compared with the cytosol (โผ20 mm, pH 7.4). Upon agonist washout and restoration of cytosolic Ca(2+) and pH, mitochondria alkalinized and ฮpH(m) increased. In permeabilized cells, a decrease in bath pH from 7.4 to 7.2 rapidly decreased mitochondrial pH, whereas the addition of 10 ฮผm Ca(2+) caused a delayed and smaller alkalinization. These findings indicate that the mitochondrial matrix pH and ฮpH(m) are regulated by opposing Ca(2+)-dependent processes of stimulated mitochondrial respiration and cytosolic acidification.
โข Bioblast editor: Gnaiger E
Cited by
- Gnaiger E (2020) Mitochondrial pathways and respiratory control. An introduction to OXPHOS analysis. 5th ed. Bioenerg Commun 2020.2. https://doi.org/10.26124/bec:2020-0002
Labels: MiParea: Respiration
Tissue;cell: HeLa Preparation: Permeabilized cells, Intact cells
Regulation: Calcium, pH Coupling state: LEAK, ROUTINE
BEC 2020.2