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Updated: Aug 10, 2026

Substrate Generation for Endonucleases of CRISPR/Cas Systems
Published on: September 9, 2012
Procaspase-3 and poly(ADP)ribose polymerase (PARP) are calpain substrates
K M McGinnis1, M E Gnegy, Y H Park
1Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
Abstract:
We demonstrate here that both procaspase-3 (32 kDa) and PARP are calpain substrates. In calcium-channel opener maitotoxin-treated cells, a 30 kDa caspase-3 fragment is produced in a time and concentration-dependent manner. Formation of this fragment is prevented by calpain inhibitors but not by the pancaspase inhibitor, carbobenzoxy-Asp-CH(2)OC(O)-2,6-dichlorobenzene (Z-D-DCB) nor the selective proteasome inhibitor lactacystin. In maitotoxin-treated cells, PARP (113 kDa) is also cleaved into a 40 kDa immunoreactive fragment, in a calpain-inhibitor-sensitive manner. Both procaspase-3 and PARP are also cleaved in vitro by purified micro-calpain to a 30 kDa fragment and a 40 kDa fragment, respectively. Finally, we show that staurosporine-mediated caspase-3 activation is interrupted by maitotoxin pretreatment.
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