Processing of the Nedd2 precursor by ICE-like proteases and granzyme B.
BACKGROUND
The Nedd2/Ich-1 protein belongs to a growing family of mammalian cysteine proteases similar to interleukin-1 beta converting enzyme (ICE). Because of their similarity to the Cacnorhabditis elegans cell death protein CED-3, the ICE-like proteins are thought to play a key role in the execution of apoptosis. The active form of ICE is a tetramer consisting of two heterodimers (p20 + p10)2 derived from the cleavage of the pro-enzyme.


RESULTS
In the present communication we show that the p51 Nedd2 precursor (pro-Nedd2) is also cleaved into p20-like (p19) and p10-like (p12) subunits by extracts prepared from cultured cell lines. Extracts from apoptotic NIH-3T3 cells but not normal growing NIH-3T3 cells also contained pro-Nedd2 cleaving activity. The processing of pro-Nedd2 by cell extracts was inhibited by characteristic inhibitors of ICE-like proteases. Additionally we show that pro-Nedd2 (p51) can be processed in vitro by active CPP32 and ICE, and to a lesser extent by Mch2 and Nedd2. Granzyme B, a serine protease required for cytotoxic T lymphocyte (CTL) mediated killing of target cells, also cleaved pro-Nedd2 to p19 + p12 subunits.


CONCLUSIONS
Our observations suggest that Nedd2 activation requires cleavage by one or more ICE-like proteases that lie upstream in the proteolytic cascade. Cleavage of pro-Nedd2 by granzyme B indicates that Nedd2 may be one of the downstream effectors in the CTL-mediated killing of target cells.
Harvey
N L
NL
Hanson Centre for Cancer Research, Institute of Medical and Veterinary Science, Adelaide, Australia.
Trapani
J A
JA
Fernandes-Alnemri
T
T
Litwack
G
G
Alnemri
E S
ES
Kumar
S
S
D016475:3T3 Cells; D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D017173:Caenorhabditis elegans; D020170:Caspase 1; D053143:Caspase 2; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004792:Enzyme Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053804:Granzymes; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D011480:Protease Inhibitors / Q000494:pharmacology; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism*; D013602:T-Lymphocytes, Cytotoxic / Q000378:metabolism
D017931:DNA Primers; D004792:Enzyme Precursors; D011480:Protease Inhibitors; D011994:Recombinant Proteins; C509213:GZMB protein, human; D053804:Granzymes; C509214:Gzmb protein, mouse; D012697:Serine Endopeptidases; C490360:CASP2 protein, human; C090208:Casp2 protein, mouse; D053143:Caspase 2; D003546:Cysteine Endopeptidases; D020170:Caspase 1