Multiple cell death programs: Charon's lifts to Hades.
Cells use different pathways for active self-destruction as reflected by different morphology: while in apoptosis (or "type I") nuclear fragmentation associated with cytoplasmic condensation but preservation of organelles is predominant, autophagic degradation of cytoplasmic structures preceding nuclear collapse is a characteristic of a second type of programmed cell death (PCD). The diverse morphologies can be attributed--at least to some extent--to distinct biochemical and molecular events (e.g. caspase-dependent and -independent death programs; DAP-kinase activity, Ras-expression). However, apoptosis and autophagic PCD are not mutually exclusive phenomena. Rather, diverse PCD programs emerged during evolution, the conservation of which apparently allows cells a flexible response to environmental changes, either physiological or pathological.
Institut für Krebsforschung der Medizinischen Universität Wien, Borschkegasse 8a, A-1090 Vienna, Austria. wilfried.bursch@meduniwien.ac.at
Wilfried
W
Bursch
D017209:Apoptosis / Q000502:physiology*; D001343:Autophagy / Q000502:physiology*; D020169:Caspases / Q000502:physiology; D003599:Cytoskeleton / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D015003:Yeasts / Q000502:physiology*
D020169:Caspases