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.
Copyright 1999 Academic Press.
MeSH terms
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Acetylcysteine / analogs & derivatives
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Acetylcysteine / pharmacology
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Aspartic Acid / analogs & derivatives
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Aspartic Acid / pharmacology
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Calpain / metabolism*
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Caspase 3
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Caspase Inhibitors
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Caspases / chemistry
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Caspases / metabolism*
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Cell Line
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Cysteine Proteinase Inhibitors / pharmacology
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Enzyme Activation / drug effects
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Enzyme Precursors / antagonists & inhibitors
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Enzyme Precursors / chemistry
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Enzyme Precursors / metabolism*
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Humans
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Marine Toxins / pharmacology
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Oxocins*
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Poly(ADP-ribose) Polymerases / metabolism*
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Protein Processing, Post-Translational / drug effects
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Staurosporine / pharmacology
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Substrate Specificity
Substances
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Caspase Inhibitors
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Cysteine Proteinase Inhibitors
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Enzyme Precursors
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Marine Toxins
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Oxocins
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benzyloxycarbonyl-Asp-CH2OC(O)-2,6-dichlorobenzene
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lactacystin
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Aspartic Acid
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maitotoxin
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Poly(ADP-ribose) Polymerases
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CASP3 protein, human
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Calpain
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Caspase 3
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Caspases
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Staurosporine
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Acetylcysteine