nature insights: Apoptosis

Apoptosis
Vol. 407, No. 6805 (12 October 2000).
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Cover illustration
Coloured scanning electron micrograph showing a killer T lymphocyte (orange) inducing a cancer cell (mauve) to undergo programmed cell death or apotosis. Mauve vesicles are apototic bodies emerging from the cancer cell. (Image courtesy of A. Liepins/SPL.)

Programmed cell death, or apoptosis, is currently one of the hottest areas of modern biology. It describes the orchestrated collapse of a cell, staging membrane blebbing, cell shrinkage, protein fragmentation, chromatin condensation and DNA degradation followed by rapid engulfment of corpses by neighbouring cells.

The excitement ensued when it became clear that apoptosis is an essential part of life for any multicellular organism and that the way in which most cells die is conserved from worm to mammal. Optimum body maintenance means that about 10 billion of our cells will die on a normal day just to counter the numbers of new cells that arise through mitosis. During development apoptosis helps to sculpture the body, shape the organs, and carve out fingers and toes. Both the nervous system and the immune system arise through overproduction of cells followed by the death of those that fail to establish functional synaptic connections or productive antigen specificities, respectively. Apoptosis is necessary to purge the body of pathogen-invaded cells, but is also needed to eliminate activated or auto-aggressive immune cells.

Such massacre has to be tightly regulated as too little or too much cell death may lead to pathology, including developmental defects, autoimmune diseases, neurodegeneration or cancer. Not surprisingly then that the hunt is on to understand which cells die when, why and how precisely, and to find drugs that interfere with specific steps along the pathway. Naturally, with over 50,000 publications on the subject to date (source: ISI-Web of Science), it is impossible to be comprehensive, but we hope that this Nature Insight provides our readers with a taster of the latest developments in this rapidly moving field.

Marie-Thérèse Heemels Senior Editor