Effect of cytosolic Mg2+ on mitochondrial Ca2+ signaling

Gergo Szanda, Anikó Rajki, Sonia Gallego-Sandín, Javier Garcia-Sancho, András Spät

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28 Citations (Scopus)


Cytosolic Ca2+ signals are followed by mitochondrial Ca 2+ uptake, which, in turn, modifies several biological processes. Mg2+ is known to inhibit Ca2+ uptake by isolated mitochondria, but its significance in intact cells has not been elucidated. In HEK293T cells, activation of purinergic receptors with extracellular ATP caused cytosolic Ca2+ signals associated with parallel changes in cytosolic [Mg2+]. Neither signals were affected by omitting bivalent cations from the extracellular medium. The effect of store-operated Ca2+ influx on cytosolic Mg2+ concentration ([Mg2+] c) was negligible. Uncaged Ca2+ displaced Mg2+ from cytosolic binding sites, but for an equivalent Ca2+ signal, the change in [Mg2+] was significantly smaller than that measured after adding extracellular ATP. Inositol 1,4,5-trisphosphate mobilized Ca2+ and Mg2+ from internal stores in permeabilized cells. The increase of [Mg2+] in the range that occurred in ATP-stimulated cells inhibited mitochondrial Ca2+ uptake in permeabilized cells without affecting mitochondrial Ca2+ efflux. Therefore, the Mg2+ signal generated by Ca2+ mobilizing agonists may attenuate mitochondrial Ca2+ uptake.

Original languageEnglish
Pages (from-to)941-954
Number of pages14
JournalPflugers Archiv European Journal of Physiology
Issue number4
Publication statusPublished - Feb 1 2009



  • ATP
  • Ca signal
  • Ca uptake
  • Inositol 1,4,5-trisphosphate
  • Magnesium
  • Mitochondria

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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