title: Activation of the apoptotic protease CPP32 by cytotoxic T-cell-derived granzyme B.
abstract: Cytotoxic T lymphocyte (CTL)-mediated cytotoxicity represents the body's major defence against virus-infected and tumorigenic cells, and contributes to transplant rejection and autoimmune disease. During killing, CTL granules are exocytosed, releasing their contents into the intercellular space between the target cell and the effector. Perforin facilitates the entry of cytotoxic cell serine proteases, the granzymes, into the target cell, where they induce apoptotic death by an unknown pathway. Granzyme B is essential for the induction of DNA fragmentation and apoptosis in target cells, yet its substrate is unknown. Identification of the intracellular substrate for granzyme B is therefore the key to understanding the mechanism of CTL-mediated killing. Here we show that granzyme B cleaves and activates CPP32, the precursor of the protease responsible for cleavage of poly(ADP-ribose) polymerase.
authors.affiliation: Department of Biochemistry, University of Alberta, Edmonton, Canada.
authors.forename: A J
authors.initials: AJ
authors.lastname: Darmon
authors.forename: D W
authors.initials: DW
authors.lastname: Nicholson
authors.forename: R C
authors.initials: RC
authors.lastname: Bleackley
mesh_terms: D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases; D002460:Cell Line; D002853:Chromatography, Liquid; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004260:DNA Repair; D004789:Enzyme Activation; D053804:Granzymes; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism*; D013602:T-Lymphocytes, Cytotoxic / Q000201:enzymology*
chemical_list: D011498:Protein Precursors; D011994:Recombinant Proteins; D011065:Poly(ADP-ribose) Polymerases; D053804:Granzymes; D012697:Serine Endopeptidases; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases