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Analyses of Mitochondrial Calcium Influx in Isolated Mitochondria and Cultured Cells
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Analyses of Mitochondrial Calcium Influx in Isolated Mitochondria and Cultured Cells

Published on: April 27, 2018

Ca2+ -dependent inactivation of the mitochondrial Ca2+ uniporter involves proton flux through the ATP synthase

Ben Moreau1, Anant B Parekh

  • 1Department of Physiology, Anatomy and Genetics, Oxford University, Parks Road, Oxford OX1 3PT, UK.

Current Biology : CB
|June 3, 2008
PubMed

Insights

Mitochondria regulate cellular calcium (Ca2+) signaling via the mitochondrial calcium uniporter. This study reveals that matrix pH influences uniporter inactivation, with the F(1)F(0)-ATP synthase complex providing protons for this process.

Area of Science:

  • Cellular biology
  • Mitochondrial function
  • Ion channel regulation

Background:

  • Intracellular calcium (Ca2+) concentration is a critical second messenger regulating numerous cellular processes.
  • Mitochondria buffer cytosolic Ca2+ via the mitochondrial calcium uniporter (MCU).
  • Uniporter activity is subject to inactivation, a process poorly understood but vital for Ca2+ signaling.

Purpose of the Study:

  • To elucidate the molecular mechanism underlying mitochondrial calcium uniporter inactivation.
  • To investigate the role of matrix pH in regulating MCU inactivation.
  • To identify cellular components involved in MCU inactivation.

Main Methods:

  • Experimental manipulation of mitochondrial matrix pH.
  • Measurement of mitochondrial Ca2+ uptake.
  • Investigation of the role of F(1)F(0)-ATP synthase in MCU inactivation.

Main Results:

  • Mitochondrial matrix alkalinization reduces MCU inactivation, while acidification enhances it.
  • The F(1)F(0)-ATP synthase complex acts as a source of protons contributing to MCU inactivation.
  • These findings reveal a novel pH-dependent regulatory mechanism for the MCU.

Conclusions:

  • Matrix pH is a key regulator of mitochondrial calcium uniporter activity.
  • The F(1)F(0)-ATP synthase contributes to MCU inactivation by providing protons.
  • This mechanism links mitochondrial bioenergetics to intracellular Ca2+ signaling and cellular function.

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