Page 3 - Academic Press Encyclopedia of Physical Science and Technology 3rd Molecular Biology

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Encyclopedia of Physical Science and Technology EN002G-90 May 17, 2001 20:42

Cell Death(Apoptosis)

Masato Enari
Imperial College School of Medicine at St. Mary’s

I. Overview
II. Death Factors and Their Receptors
III. Apoptotic Proteases, Caspases
IV. Signal Transduction of Death
Factor-Mediated Apoptosis
V. Cell-Free System in Apoptosis
VI. Apoptotic DNase, CAD and Its Inhibitor, ICAD
VII. Molecular Mechanism of CAD and ICAD
VIII. Physiological DNA Fragmentation and
Phagocytosis of Apoptotic Cells
IX. Perspectives

GLOSSARY cells expressing their corresponding receptors or to at-
tenuate killing activity.
Apoptosis The typical process in physiological cell death DNases Enzymes possessing DNA-cleaving activity.
that is accompanied by nuclear and cytoplasmic con- Some DNases participate in chromosomal DNA degra-
densation, fragmentation of cell bodies, chromosomal dation during apoptosis.
DNA fragmentation, loss of mitochondrial function, DNA fragmentation Chromosomal DNA from apoptotic
and alterations of cell membrane composition. It is cells gives rise to a ladder pattern on agarose gels, due
distinct in these regards from necrosis. The term was to multimeric nucleosomal units (∼180 base pairs).
created by Wyllie and Kerr. Death receptors Proteins belonging to TNF receptor
Caspases Cysteine proteases, some of which are acti- family that occur on cell surface, and mediate killing
vated during apoptosis. Some caspases are involved by effector cells expressing their cognate ligands.
in processing of cytokines. Intracellular signal transduction The cellular machin-
Cell-free system A biochemical technique to be recon- ery that mediates external signals including hor-
stituted cellular events as in vitro reaction. mones, neurotransmitters, cell growth, differentiation
Death factors Proteins belonging to the tumor necrosis and death factors, or stress to their ultimate targets.
factor (TNF) superfamily that occur on the cell sur- Phagocytosis The process by which phagocytes, such as
faces as membrane-bound factors and in the extracel- macrophages and neutrophils, engulf useless and un-
lular compartment as soluble factors. They kill target necessary cells.

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