Journal of Cell Science 116, e1504 (2003)
Copyright © 2003 The Company of Biologists Limited
Clusterin - an apoptotic puzzle
Clusterin is a chaperone protein that is synthesized in response to
cellular stress. It often appears in cells undergoing apoptosis - both as part
of developmental programmes such as tissue involution and in numerous
pathological conditions - but has also been reported to confer resistance to
apoptosis in some cases. Whether it is a pro-survival or a pro-death molecule
is therefore unclear. Laure Debure and co-workers have examined the effects of
clusterin expression in COS-7 cells (see
p. 3109). They find
that clusterin can accumulate in juxtanuclear aggregates that exhibit features
characteristic of aggresomes (inclusion bodies thought to prevent misfolded
proteins spreading throughout the cell). They have a vimentin cage, for
example, and can be disrupted by treatment with the chaperone Hsp70 or
microtubule-depolymerising drugs. The authors also observe, however, that
clusterin expression disrupts mitochondria and induces apoptosis through the
mitochondrial pathway - this can be prevented by expression of the
pro-survival molecule Bcl-2 or inhibition of caspases. Debure and co-workers
reconcile these seemingly conflicting effects on cell survival by suggesting
that clusterin is an anti-apoptotic, aggresome-forming chaperone but can be
cytotoxic if it accumulates.

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Related articles in JCS:
- Intracellular clusterin causes juxtanuclear aggregate formation and mitochondrial alteration
- Laure Debure, Jean-Luc Vayssière, Vincent Rincheval, Fabien Loison, Yves Le Dréan, and Denis Michel
JCS 2003 116: 3109-3121.
[Abstract]
[Full Text]