Distinct cleavage products of nuclear proteins in apoptosis and necrosis revealed by autoantibody probes.
A central mechanism in apoptosis is the activation of proteases of the caspase (cysteine aspartases) family. Protease activation has also been implicated in necrosis, but its role in this cell death process and the identity of the proteases involved and their substrates, are unknown. Using human autoantibodies to well characterized cellular proteins as detecting probes in immunoblotting, we observed that a defined and somewhat similar set of nuclear proteins, including poly (ADP-ribose) polymerase (PARP) and DNA topoisomerase I (Topo I), were selectively cleaved during both apoptosis and necrosis of cultured cells induced by various stimuli. The resulting cleavage products were distinctively different in the two cell death pathways. In contrast to apoptosis, the cleavages of PARP and Topo I during necrosis were not blocked by the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (zVAD-fmk). These findings suggest that different proteases act in apoptosis and necrosis, and that although both cell death processes result in selective cleavage of almost identical cellular proteins, they can be distinguished immunochemically on the basis of their cleavage products.
Casiano
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WM Keck Autoimmune Disease Center, Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA. ccasiano@scripps.edu
Ochs
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Tan
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D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001323:Autoantibodies / Q000494:pharmacology*; D001324:Autoantigens / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D003902:Detergents; D018922:HL-60 Cells; D006801:Humans; D019169:Jurkat Cells; D008854:Microscopy, Electron; D009336:Necrosis; D009687:Nuclear Proteins / Q000276:immunology* / Q000378:metabolism*; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D011506:Proteins / Q000378:metabolism; D019014:fas Receptor / Q000032:analysis / Q000276:immunology / Q000378:metabolism
D000590:Amino Acid Chloromethyl Ketones; D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D001324:Autoantigens; D015853:Cysteine Proteinase Inhibitors; D003902:Detergents; D009687:Nuclear Proteins; D011506:Proteins; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D019014:fas Receptor; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases