Related Experiment Video

Updated: Aug 10, 2026

Examining BCL-2 Family Function with Large Unilamellar Vesicles
08:35

Examining BCL-2 Family Function with Large Unilamellar Vesicles

Published on: October 5, 2012

The increase in mitochondrial association with actin precedes Bax translocation in apoptosis

Ho Lam Tang1, Anh-Huy Phan Le, Hong Lok Lung

  • 1Department of Biology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (SAR), People's Republic of China.

The Biochemical Journal
|March 16, 2006
PubMed

Insights

Actin accumulation at mitochondria precedes key apoptosis events, suggesting its role in initiating programmed cell death. This actin cytoskeleton involvement is a general phenomenon in mammalian cells during apoptosis.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • The actin cytoskeleton is implicated in recruiting pro-apoptotic proteins to mitochondria.
  • The precise role of actin in initiating apoptosis requires further elucidation.

Purpose of the Study:

  • To investigate the role of actin cytoskeleton in the early stages of apoptosis.
  • To determine the temporal relationship between actin accumulation at mitochondria and other apoptosis markers.

Main Methods:

  • Cell fractionation and Western blot analysis to quantify protein levels.
  • Fluorescence microscopy to visualize actin reorganization and mitochondrial association.
  • Utilized various cell lines and apoptotic stimuli.

Main Results:

  • Mitochondrial accumulation of beta-actin was observed in early apoptosis, preceding Bax insertion and cytochrome c release.
  • Apoptotic induction led to F-actin network reorganization and increased mitochondrial association before mitochondrial fission and nuclear condensation.
  • This phenomenon was consistent across different cell lines and apoptotic stimuli.

Conclusions:

  • Actin accumulation at mitochondria is an early and general event in mammalian apoptosis.
  • The actin cytoskeleton may facilitate apoptosis by trafficking cytosolic pro-apoptotic proteins to mitochondria.

More Related Videos

Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation08:47

Lighting Up the Pathways to Caspase Activation Using Bimolecular Fluorescence Complementation

Published on: March 5, 2018

Related Concept Videos

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 Extrinsic Apoptotic Pathway01:17

The Extrinsic Apoptotic Pathway

The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
Translocation of Proteins into the Mitochondria01:19

Translocation of Proteins into the Mitochondria

Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
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.
Autophagic Cell Death01:18

Autophagic Cell Death

Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
Cellular Injury V: Apoptosis and Autophagy01:22

Cellular Injury V: Apoptosis and Autophagy

Cells respond to damage and stress through highly coordinated processes that decide whether they survive or undergo controlled self-destruction. Two major pathways involved in this regulation are apoptosis, a type of programmed cell death, and autophagy, a survival mechanism that helps cells adapt to adverse conditions.ApoptosisApoptosis removes aged or injured cells to maintain tissue balance. During this process, the cell shrinks, chromatin condenses and fragments, and membrane-bound...