Looking for death at the core of life in the light of evolution

Classification of cell death: recommendations of the Nomenclature Committee on Cell Death

“…As an example, it appears counterintuitive that some cells exert essential functions when they are 'dead' (such as erythrocytes and keratinocytes), and this underscores the importance of clearly defining what is referred to as 'cell death' as well as the multiple processes leading to it. Knowing that the meaning of scientific words changes when knowledge advances and that words, especially when they express changing concepts, [1][2][3][4] can increase confusion, one may adopt one of two opposing views. A significant fraction of the community of cell death researchers refutes nomenclature as an intellectual cage and as forever 'premature', remembering that many investigators desperately searched for 'DNA ladders' during the 1980s and 1990s.…”

How many ways to die? How many different models of cell death?

“…Rather than classifying or subdividing cell death according to appearances, I am convinced that we should perhaps consider that cells can engage multiple death Figure 1 Common sense concepts on cell death. The mythological interpretation of cell death has been discussed by Ameisen [43][44][45] and Melino. 1 Ameisen also describes the apparent counterselectivity of the concept of apoptosis (the occurrence of the cell death genetic programme impedes its transmission to the progeny), suggesting that this pathway evolved from proteins designed for other purposes.…”

“…Animals that lack skin (and cornification), such as C. elegans and Drosophilla melanogaster, still have a well-developed apoptotic machinery, as elegantly described by Jean-Claude Ameisen. [43][44][45] Specific subroutines of cornification, namely the elimination of nucleus and mitochondria, also appear in different peculiar nonapoptotic forms of cell death, possibly suggesting a common origin (at least for some subroutines). Cornification and apoptosis are therefore an example of divergent evolution.…”

“…1,12,24,[43][44][45] Definitions of different forms or routines include: necrosis, apoptosis, cornification, Wallerian degeneration, caspase-independent apoptosis, platelet formation, erythropoiesis and autophagocytosis. Definitions have always attracted debates, as originally discussed in this journal, 46,47 and in the present issue.…”

Apoptosis in yeast: triggers, pathways, subroutines

“…This functional conservation reaches back to worms such as Caenorhabditis elegans (emerged 700 million years ago), 15 the plant kingdom (1 billion years), 16 unicellular eukaryotes (1-2 billion years), 2 and even bacteria (4 billion years). 17 Thus, evolution seems to persistently select cellular self-destruction mechanisms, which over time have been harnessed and refined with the growing complexity of organisms. Death regulation as an integral part of cellular organization has, hence, contributed to the propagation of life in the course of natural history.…”