|
|
|
|
|
|
|
||
J. Cell Biol.,
Volume 144, Number 5, March 8, 1999 915-926
* IDUN Pharmaceuticals, La Jolla, California 92037; and The mechanism by which membrane-bound
Bcl-2 inhibits the activation of cytoplasmic procaspases
is unknown. Here we characterize an intracellular, membrane-associated form of procaspase-3 whose activation is controlled by Bcl-2. Heavy membranes isolated
from control cells contained a spontaneously activatable caspase-3 zymogen. In contrast, in Bcl-2 overexpressing cells, although the caspase-3 zymogen was still
associated with heavy membranes, its spontaneous activation was blocked. However, Bcl-2 expression had little effect on the levels of cytoplasmic caspase activity in
unstimulated cells. Furthermore, the membrane-associated caspase-3 differed from cytosolic caspase-3 in its
responsiveness to activation by exogenous cytochrome
c. Our results demonstrate that intracellular membranes can generate active caspase-3 by a Bcl-2-inhibitable mechanism, and that control of caspase activation in membranes is distinct from that observed in the
cytoplasm. These data suggest that Bcl-2 may control
cytoplasmic events in part by blocking the activation of
membrane-associated procaspases.
Novartis Pharma AG, CH-4002 Basel, Switzerland
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
