title: Bcl-2 expression prevents activation of the ICE protease cascade.
abstract: The Bcl-2 family and the ICE family of cysteine proteases play important roles in regulating cell death. We show here that induction of cell death by a Ca2+ ionophore or hypoxia results in increased levels and activity of active ICE(-like) proteases and the subsequent activation of CPP32/Yama(-like) proteases, and that inhibition of these protease activities reduces the extent of cell death. Overexpression of the anti-apoptotic proteins Bcl-2 or Bcl-xL inhibits the cell death and the activation of ICE(-like) and CPP32/Yama(-like) proteases, indicating that Bcl-2 and Bcl-xL act upstream of these proteases. We also show that specific inhibition of ICE(-like) proteases in vivo prevents activation of CPP32/Yama(-like) proteases, whereas inhibition of CPP32/Yama(-like) proteases does not prevent activation of ICE(-like) proteases, suggesting the existence of a protease cascade in vivo that requires ICE(-like) proteases for activation of CPP32/Yama(-like) proteases. Induction of necrotic cell death by KCN also induces activation of ICE(-like) proteases but not of CPP32/Yama(-like) proteases, and Bcl-2 and Bcl-xL inhibit the activation and the cell death, suggesting that the functional site of Bcl-2 and Bcl-xL is also upstream of ICE(-like) proteases in at least some forms of necrosis.
authors.affiliation: First Department of Surgery, Osaka University Medical School, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Shimizu
authors.forename: Y
authors.initials: Y
authors.lastname: Eguchi
authors.forename: W
authors.initials: W
authors.lastname: Kamiike
authors.forename: H
authors.initials: H
authors.lastname: Matsuda
authors.forename: Y
authors.initials: Y
authors.lastname: Tsujimoto
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000378:metabolism / Q000473:pathology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D000001:Calcimycin / Q000494:pharmacology; D020170:Caspase 1; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases / Q000502:physiology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D000860:Hypoxia; D007476:Ionophores / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology; D010673:Pheochromocytoma / Q000378:metabolism / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2; D051381:Rats; D014407:Tumor Cells, Cultured
chemical_list: D015853:Cysteine Proteinase Inhibitors; D007476:Ionophores; D009842:Oligopeptides; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C099158:acetyl-aspartyl-glutamyl-valyl-aspartal; D000001:Calcimycin; C505407:CASP3 protein, human; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases; D020170:Caspase 1