No death without life: vital functions of apoptotic effectors

Cell Death Differ. 2008 Jul;15(7):1113-23. doi: 10.1038/cdd.2008.28. Epub 2008 Feb 29.

Abstract

As a result of the genetic experiments performed in Caenorhabditis elegans, it has been tacitly assumed that the core proteins of the 'apoptotic machinery' (CED-3, -4, -9 and EGL-1) would be solely involved in cell death regulation/execution and would not exert any functions outside of the cell death realm. However, multiple studies indicate that the mammalian orthologs of these C. elegans proteins (i.e. caspases, Apaf-1 and multidomain proteins of the Bcl-2 family) participate in cell death-unrelated processes. Similarly, loss-of-function mutations of ced-4 compromise the mitotic arrest of DNA-damaged germline cells from adult nematodes, even in a context in which the apoptotic machinery is inoperative (for instance due to mutations of egl-1 or ced-3). Moreover, EGL-1 is required for the activation of autophagy in starved nematodes. Finally, the depletion of caspase-independent death effectors, such as apoptosis-inducing factor (AIF) and endonuclease G, provokes cell death-independent consequences, both in mammals and in yeast (Saccharomyces cerevisiae). These results corroborate the conjecture that any kind of protein that has previously been specifically implicated in apoptosis might have a phylogenetically conserved apoptosis-unrelated function, most likely as part of an adaptive response to cellular stress.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adaptation, Physiological
  • Animals
  • Apoptosis Regulatory Proteins / genetics
  • Apoptosis Regulatory Proteins / metabolism*
  • Apoptosis* / genetics
  • Caspases / metabolism
  • Evolution, Molecular
  • Humans
  • Mitochondrial Membrane Transport Proteins / metabolism
  • Mitochondrial Permeability Transition Pore
  • Mitochondrial Proteins / metabolism
  • Signal Transduction* / genetics

Substances

  • Apoptosis Regulatory Proteins
  • Mitochondrial Membrane Transport Proteins
  • Mitochondrial Permeability Transition Pore
  • Mitochondrial Proteins
  • Caspases