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Origin and evolution of eukaryotic apoptosis: the bacterial connection
1National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA. koonin@ncbi.nlm.nih.gov
Cell Death and Differentiation
|April 20, 2002
Summary
The origin of eukaryotic apoptosis involves acquiring bacterial proteins, particularly from mitochondria and Actinomycetes. These bacterial homologs may have functioned in signaling pathways before eukaryotic integration.
Area of Science:
- Evolutionary biology
- Molecular biology
- Cell biology
Background:
- Eukaryotic genomes possess unique functional systems with origins not fully understood.
- Key apoptotic machinery components like caspases, ATPases, and proteases have bacterial, but not archaeal, homologs.
Purpose of the Study:
- To investigate the evolutionary origins of eukaryotic apoptotic systems.
- To identify bacterial ancestors of key eukaryotic apoptotic proteins.
Main Methods:
- Phylogenetic analysis of prokaryotic and eukaryotic genome sequences.
- Comparative genomics to trace the evolutionary history of apoptotic protein families.
Main Results:
- Metacaspases and HtrA-like proteases likely originated from mitochondria.
- AP-ATPases were probably acquired from Actinomycetes bacteria.
- Bacterial homologs are abundant in complex developmental bacteria like Actinomycetes, Cyanobacteria, and alpha-proteobacteria.
Conclusions:
- Eukaryotic apoptosis likely arose from endosymbiosis with mitochondria and horizontal gene transfer.
- Bacterial multidomain proteins containing apoptosis-related domains may have interacted within signaling pathways.
- Further research is needed to elucidate the function and interaction of these bacterial homologs.