Granzyme A activates an endoplasmic reticulum-associated caspase-independent nuclease to induce single-stranded DNA nicks.
The cytotoxic T lymphocyte protease granzyme A (GzmA) initiates a novel caspase-independent cell death pathway characterized by single-stranded DNA nicking. The previously identified GzmA substrate SET is in a multimeric 270-420-kDa endoplasmic reticulum-associated complex that also contains the tumor suppressor protein pp32. GzmA cleaved the nucleosome assembly protein SET after Lys(176) and disrupted its nucleosome assembly activity. The purified SET complex required only GzmA to reconstitute single-stranded DNA nicking in isolated nuclei. DNA nicking occurred independently of caspase activation. The SET complex contains a 25-kDa Mg(2+)-dependent nuclease that degrades calf thymus DNA and plasmid DNA. Thus, GzmA activates a DNase (GzmA-activated DNase) within the SET complex to produce a novel form of DNA damage during cytotoxic T lymphocyte-mediated death.
Beresford
P J
PJ
Center for Blood Research and the Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.
Zhang
D
D
Oh
D Y
DY
Fan
Z
Z
Greer
E L
EL
Russo
M L
ML
Jaju
M
M
Lieberman
J
J
D000595:Amino Acid Sequence; D000818:Animals; D020169:Caspases / Q000378:metabolism*; D016923:Cell Death; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D004249:DNA Damage; D018076:DNA, Complementary / Q000378:metabolism; D004277:DNA, Single-Stranded; D003851:Deoxyribonucleases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004721:Endoplasmic Reticulum / Q000201:enzymology*; D004789:Enzyme Activation; D015723:Gene Library; D053804:Granzymes; D006801:Humans; D008274:Magnesium / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000737:chemistry; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D054353:Perforin; D010957:Plasmids / Q000378:metabolism; D052899:Pore Forming Cytotoxic Proteins; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000494:pharmacology*; D014158:Transcription, Genetic
D018076:DNA, Complementary; D004277:DNA, Single-Stranded; D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D011994:Recombinant Proteins; D054353:Perforin; D003851:Deoxyribonucleases; D053804:Granzymes; D012697:Serine Endopeptidases; C509212:GZMA protein, human; D020169:Caspases; D008274:Magnesium