Volume 272, Number 20,
Issue of May 16, 1997
pp. 13134-13139
©1997 by The American Society for Biochemistry and Molecular Biology, Inc.
Functional Activation of Nedd2/ICH-1 (Caspase-2) Is an Early
Process in Apoptosis
(Received for publication, February 20, 1997)
Natasha L.
Harvey
,
Alison J.
Butt
and
Sharad
Kumar
From the Hanson Centre for Cancer Research, Institute of Medical
and Veterinary Science, Rundle Mall, Adelaide,
SA 5000, Australia
The ICE/CED-3 family of proteases (caspases) play
a central role in the execution phase of apoptosis. These proteases are synthesised as precursor molecules that require processing at specific
aspartate residues to produce the two subunits that comprise the active
enzyme. The activation of some of these proteases has been shown to
occur during apoptosis. Here we show that Nedd2/ICH-1 (caspase-2) is
activated during apoptosis induced by a variety of apoptotic stimuli.
This activation occurs very early upon treatment of cells with
apoptotic agents and appears to precede the activation of CPP32
(caspase-3). The activation of Nedd2 was not seen in cells that are
resistant to apoptosis. These observations suggest that Nedd2 is an
early effector in the pathway leading to cell death. Our observations
also lend weight to the hypothesis that a group of caspases containing
long prodomains are the first to be activated in response to apoptotic
signals and that they lie upstream of a second class of caspases such
as CPP32 containing short or no prodomains.