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Direct cleavage of the human DNA fragmentation factor‐45 by granzyme B induces caspase‐activated DNase release and DNA fragmentation
Author(s) -
SharifAskari Ehsan,
Alam Antoine,
Rhéaume Eric,
Beresford Paul J.,
Scotto Christian,
Sharma Kamal,
Lee Dennis,
DeWolf Walter E.,
Nuttall Mark E.,
Lieberman Judy,
Sékaly RafickPierre
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.12.3101
Subject(s) - biology , dna fragmentation , granzyme b , fragmentation (computing) , apoptotic dna fragmentation , microbiology and biotechnology , dna , deoxyribonuclease i , cleavage (geology) , nlrp1 , caspase , apoptosis , genetics , in vitro , programmed cell death , cytotoxic t cell , base sequence , ecology , paleontology , fracture (geology)
The protease granzyme B (GrB) plays a key role in the cytocidal activity during cytotoxic T lymphocyte (CTL)‐mediated programmed cell death. Multiple caspases have been identified as direct substrates for GrB, suggesting that the activation of caspases constitutes an important event during CTL‐induced cell death. However, recent studies have provided evidence for caspase‐independent pathway(s) during CTL‐mediated apoptosis. In this study, we demonstrate caspase‐independent and direct cleavage of the 45 kDa unit of DNA fragmentation factor (DFF45) by GrB both in vitro and in vivo . Using a novel and selective caspase‐3 inhibitor, we show the ability of GrB to process DFF45 directly and mediate DNA fragmentation in the absence of caspase‐3 activity. Furthermore, studies with DFF45 mutants reveal that both caspase‐3 and GrB share a common cleavage site, which is necessary and sufficient to induce DNA fragmentation in target cells during apoptosis. Together, our data suggest that CTLs possess alternative mechanism(s) for inducing DNA fragmentation without the requirement for caspases.