Poxviruses and apoptosis: a time to die
Related Experiment Video
Updated: Sep 30, 2026
10:23
Evaluation of Caspase Activation to Assess Innate Immune Cell Death
Published on: January 20, 2023
Helen Everett1, Grant McFadden
1Department of Biochemistry, University of Alberta, 4-63 Medical Sciences Building, Edmonton, T6G 2H7, Alberta, Canada. heverett@biochem.ualberta.ca
Current Opinion in Microbiology
|August 6, 2002
Abstract:
All known apoptosis modulators in poxviruses have been shown to function as inhibitors. The mechanistic classes of these poxvirus-encoded inhibitors are quite diverse, and indicate that a wide variety of distinct host proteins in cellular apoptotic pathways have been targeted for inhibition by individual poxviruses.
Insights
Poxviruses encode diverse apoptosis inhibitors that target host cell death pathways. These viral proteins function as inhibitors, highlighting complex host-pathogen interactions during infection.
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- Apoptosis, or programmed cell death, is a critical cellular process.
- Poxviruses are large DNA viruses known to manipulate host cell functions.
- Viral interference with apoptosis is a common strategy for pathogen survival and replication.
Purpose of the Study:
- To review and categorize known apoptosis modulators encoded by poxviruses.
- To understand the diversity of mechanisms employed by these viral inhibitors.
- To identify the specific host proteins targeted by poxvirus-encoded apoptosis modulators.
Main Methods:
- Literature review of published studies on poxvirus apoptosis modulators.
- Analysis of reported mechanisms of action for viral proteins.
- Comparison of targeted host proteins across different poxvirus species.
Main Results:
- All identified poxvirus-encoded apoptosis modulators function as inhibitors.
- These inhibitors exhibit diverse mechanistic classes.
- Individual poxviruses target a wide array of host proteins within cellular apoptotic pathways.
Conclusions:
- Poxviruses possess a sophisticated arsenal of apoptosis inhibitors.
- The diversity of inhibitors suggests convergent or divergent evolutionary strategies for subverting host cell death.
- Understanding these interactions is crucial for comprehending poxvirus pathogenesis.
Related Concept Videos
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...
01:30Apoptosis
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.
01:31The 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...
01:24Caspases
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.
01:18Autophagic 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...
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
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...