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Monitoring Dynamic Changes In Mitochondrial Calcium Levels During Apoptosis Using A Genetically Encoded Calcium Sensor
06:26

Monitoring Dynamic Changes In Mitochondrial Calcium Levels During Apoptosis Using A Genetically Encoded Calcium Sensor

Published on: April 1, 2011

Calcium blocks formation of apoptosome by preventing nucleotide exchange in Apaf-1

Qing Bao1, Wenyun Lu, Joshua D Rabinowitz

  • 1Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ 08544, USA.

Molecular Cell
|January 25, 2007
PubMed

Insights

Calcium ions inhibit the assembly of the apoptosome, a key complex in programmed cell death (apoptosis). This finding reveals a new regulatory mechanism for apoptosis involving calcium homeostasis and Apaf-1 protein function.

Area of Science:

  • Cell Biology
  • Biochemistry
  • Molecular Biology

Background:

  • Apoptosis, or programmed cell death, is crucial for development and tissue homeostasis.
  • Apoptotic protease activating factor 1 (Apaf-1) forms the apoptosome complex, activating caspase-9 to initiate apoptosis.
  • Mechanisms regulating apoptosome assembly are not fully understood.

Purpose of the Study:

  • To investigate the role of calcium ions in the regulation of apoptosome assembly.
  • To elucidate the impact of calcium on Apaf-1's function in apoptosis.

Main Methods:

  • Studied the effect of physiological calcium concentrations on Apaf-1 protein.
  • Assessed the inhibition of nucleotide exchange in monomeric Apaf-1.
  • Evaluated the impact of calcium on Apaf-1-mediated caspase-9 activation.

Main Results:

  • Physiological calcium concentrations inhibit apoptosome assembly.
  • Calcium ions block nucleotide exchange in the autoinhibited Apaf-1 monomer.
  • Calcium prevents Apaf-1 from activating caspase-9, thereby inhibiting apoptosis.

Conclusions:

  • Calcium ions act as a negative regulator of Apaf-1-dependent apoptosis.
  • Calcium homeostasis plays a significant role in controlling the apoptotic pathway.
  • These findings provide new insights into the molecular mechanisms of apoptosis regulation.

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