Related Experiment Video
Updated: Aug 1, 2026
07:42
Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c
Published on: June 29, 2011
[Molecular mechanisms in apoptosis].
S Habibović1, Z Hrgović, I Bukvić
1Krankenhaus Sachsenhausen, Frauenklinik, Frankfurt, Germany.
Medicinski Arhiv
|June 29, 2000
Summary
Apoptosis, a programmed cell death, is triggered by TNF-alpha or Fas Ligand, activating caspase-8. Bcl-2, a key regulator, fails to inhibit Bax-induced cell death, highlighting its role in cell fate decisions.
Area of Science:
- Cell Biology
- Molecular Biology
Context:
- Apoptosis is a fundamental biological process involving programmed cell death.
- Tumor necrosis factor-alpha (TNF-alpha) and Fas Ligand are key initiators of apoptosis.
- Caspase-8 activation is a critical early step in the apoptotic cascade.
Purpose:
- To elucidate the molecular mechanisms underlying apoptosis.
- To investigate the role of Bcl-2 in regulating cell death pathways.
- To understand the interplay between protein degradation and cell fate decisions.
Summary:
- Apoptosis is initiated by TNF-alpha or Fas Ligand binding to their respective receptors, leading to caspase-8 activation.
- The activation of caspase-8 triggers a cascade of events culminating in cell death.
- Bcl-2, a crucial regulator of cell survival, cannot prevent Bax-induced apoptosis, which involves cytochrome c release, caspase-3 activation, and characteristic morphological changes.
- Protein degradation is integral to apoptosis execution and may influence decisions between apoptosis, necrosis, and proliferation.
Impact:
- Provides insights into the intricate regulation of apoptosis.
- Highlights the critical role of Bcl-2 and caspase pathways in cell death.
- Enhances understanding of how protein degradation influences cell fate.
- Potential implications for therapeutic strategies targeting cell death in diseases like cancer.
Related Concept Videos
01:30Overview of Cell Death
Cell death is an essential process where the body gets rid of old or damaged cells. Cell proliferation and death need to be balanced, as an imbalance between the two may lead to cancer or autoimmune diseases.
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
01:30Apoptosis
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.
01:24Caspases
Caspase, a family of cysteine proteases, serve as effectors in apoptosis. The ced3 gene in C.elegans was first identified to be involved in apoptosis. This gene encodes the ced-3 caspase that is similar to the interleukin-1-beta converting enzyme or ICE in mammals. In addition to apoptosis, caspases also function in the inflammatory response. Inflammatory caspases are essential in activating pro-inflammatory cytokines that recruit immune cells and block the replication of pathogens inside cells.
01:17The 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...
01:31The 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...
01:22Cellular 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...