Related Experiment Video

Updated: Jul 9, 2026

Detection of Mitochondria Membrane Potential to Study CLIC4 Knockdown-induced HN4 Cell Apoptosis In Vitro
13:20

Detection of Mitochondria Membrane Potential to Study CLIC4 Knockdown-induced HN4 Cell Apoptosis In Vitro

Published on: July 17, 2018

The mitochondrial respiratory chain is a modulator of apoptosis

Jennifer Q Kwong1, Matthew S Henning, Anatoly A Starkov

  • 1Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10021, USA.

The Journal of Cell Biology
|December 19, 2007
PubMed

Insights

Mitochondrial respiratory chain dysfunction impacts cell death pathways differently based on electron flux. These findings reveal context-dependent apoptosis regulation, independent of ATP levels.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Genetics

Background:

  • Mitochondrial dysfunction and apoptosis dysregulation are linked to diseases like cancer and neurodegeneration.
  • Respiratory chain (RC) dysfunction is a key aspect of mitochondrial dysfunction.

Purpose of the Study:

  • To investigate the role of respiratory chain (RC) dysfunction in apoptosis using mitochondrial DNA mutations.
  • To understand how varying levels of RC dysfunction affect cellular responses to apoptotic stimuli.

Main Methods:

  • Utilizing mitochondrial DNA mutations as genetic models to create distinct RC dysfunction states.
  • Analyzing cellular apoptosis responses under different conditions of electron flux and stress.

Main Results:

  • Cells lacking RC are protected from both mitochondrial and ER stress-induced apoptosis.
  • Cells with RC but no electron flux are protected from mitochondrial apoptosis but sensitive to ER stress.
  • Partial reduction in electron flux increases apoptosis in both mitochondrial and ER stress conditions.

Conclusions:

  • The respiratory chain modulates apoptosis in a context-dependent manner, independent of ATP production.
  • Apoptotic responses are determined by the interplay between mitochondrial function and environmental cues.

More Related Videos

Isolation and Functional Analysis of Mitochondria from Cultured Cells and Mouse Tissue09:27

Isolation and Functional Analysis of Mitochondria from Cultured Cells and Mouse Tissue

Published on: March 23, 2015

Monitoring Dynamic Changes In Mitochondrial Calcium Levels During Apoptosis Using A Genetically Encoded Calcium Sensor06:26

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

Published on: April 1, 2011

Related Concept Videos

Electron Transport Chain: Complex I and II01:46

Electron Transport Chain: Complex I and II

The mitochondrial electron transport chain (ETC) is the main energy generation system in the eukaryotic cells. However, mitochondria also produce cytotoxic reactive oxygen species (ROS) due to the large electron flow during oxidative phosphorylation. While Complex I is one of the primary sources of superoxide radicals, ROS production by Complex II is uncommon and may only be observed in cancer cells with mutated complexes.
ROS generation is regulated and maintained at moderate levels necessary...
The Intrinsic Apoptotic Pathway01:31

The Intrinsic Apoptotic Pathway

Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
The Electron Transport Chain01:30

The Electron Transport Chain

The electron transport chain or oxidative phosphorylation is an exothermic process in which free energy released during electron transfer reactions is coupled to ATP synthesis. This process is a significant source of energy in aerobic cells, and therefore inhibitors of the electron transport chain can be detrimental to the cell's metabolic processes.
Inhibitors of the electron transport chain
Rotenone, a widely used pesticide, prevents electron transfer from Fe-S cluster to ubiquinone or Q in...
Mitochondrial Membranes01:45

Mitochondrial Membranes

A single mitochondrion is a bean-shaped organelle enclosed by a double-membrane system. The outer membrane of mitochondria is smooth and contains many porins - the integral membrane transporters. Porins enable free diffusion of ions and small uncharged molecules through the outer mitochondrial membrane but limit the transport of molecules larger than 5000 Daltons. Further, the outer mitochondrial membrane forms a unique structure called membrane contact sites with other subcellular organelles,...
Mitochondrial Membranes01:45

Mitochondrial Membranes

A single mitochondrion is a bean-shaped organelle enclosed by a double-membrane system. The outer membrane of mitochondria is smooth and contains many porins - the integral membrane transporters. Porins enable free diffusion of ions and small uncharged molecules through the outer mitochondrial membrane but limit the transport of molecules larger than 5000 Daltons. Further, the outer mitochondrial membrane forms a unique structure called membrane contact sites with other subcellular organelles,...
Apoptosis01:30

Apoptosis

Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size reduction of the tissue.