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Apoptosis and the cell cycle
1Imperial Cancer Research Fund Laboratories, London, UK. evan@europa.lif.icnet.uk
Abstract:
Apoptosis is an evolutionarily conserved 'suicide' programme present in all metazoan cells. Despite its highly conserved nature, it is only recently that any of the molecular mechanisms underlying apoptosis have been identified. Several lines of reasoning indicate that apoptosis and cell proliferation coincide to some degree: many oncogenes that promote cell cycle progression also induce apoptosis; damage to the cell cycle or to DNA integrity is a potent trigger of apoptosis; and the key tumour suppressor proteins, p105rb and p53, exert direct effects both on cell viability and on cell cycle progression. There is less evidence, however, to indicate that apoptosis and the cell cycle share common molecular mechanisms. Moreover, the interleukin-1 beta converting enzyme (ICE) family of cysteine proteases is now known to play a key role in apoptosis but has no discernible role in the cell cycle, arguing that the two processes are discrete.
Insights
Apoptosis, a programmed cell death, shares connections with cell proliferation, but distinct molecular mechanisms govern each process. The interleukin-1 beta converting enzyme (ICE) family is crucial for apoptosis but not the cell cycle.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Apoptosis is a conserved programmed cell death mechanism in metazoan cells.
- Recent research is identifying molecular mechanisms underlying apoptosis.
- Apoptosis and cell proliferation appear to coincide in several aspects.
Purpose of the Study:
- To explore the relationship between apoptosis and cell cycle progression.
- To investigate potential shared molecular mechanisms between apoptosis and cell proliferation.
Main Methods:
- Review of existing literature on apoptosis and cell cycle regulation.
- Analysis of the roles of oncogenes and tumor suppressor proteins (p105rb, p53) in both processes.
- Examination of the function of the ICE family of proteases.
Main Results:
- Evidence suggests overlap between apoptosis and cell proliferation triggers, including oncogenes and DNA damage.
- Key tumor suppressor proteins (p105rb, p53) influence both cell viability and cell cycle progression.
- The ICE family of proteases is critical for apoptosis but lacks a discernible role in the cell cycle.
Conclusions:
- Apoptosis and cell cycle progression are linked but appear to be regulated by distinct molecular pathways.
- The ICE family of proteases represents a key component of the apoptotic machinery, separate from cell cycle control.