Apoptosis Apoptosis Sherwin Wilk, Ph.D. Sherwin Wilk, Ph.D. Mount Sinai School of Medicine Mount Sinai School of Medicine Department of Pharmacology and Department of Pharmacology and Biological Chemistry Biological Chemistry Cell Signaling Systems Course Cell Signaling Systems Course Spring 2005 Spring 2005
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Apoptosis Sherwin Wilk, Ph.D. Mount Sinai School of Medicine Department of Pharmacology and Biological Chemistry Cell Signaling Systems Course Spring 2005.
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ApoptosisApoptosis
Sherwin Wilk, Ph.D.Sherwin Wilk, Ph.D.Mount Sinai School of MedicineMount Sinai School of Medicine
Department of Pharmacology and Biological Department of Pharmacology and Biological ChemistryChemistry
Cell Signaling Systems CourseCell Signaling Systems CourseSpring 2005Spring 2005
Wojcik, C. et al, Apoptosis. 1997;2(5):455-462.
C. elegansC. elegans Death Genes Death Genes
Pro-apoptoticPro-apoptoticcedced-3-3cedced-4-4
Anti-Anti-apoptoticapoptoticcedced-9-9
Pro-IL-1β (31 – 33 kDa)
IL-1-β converting enzyme
IL-1-β (17.5 kDa)
Single cleavage at Asp116-Ala117
Substrate specificity of Substrate specificity of ICEICE
P4-P3-P2-P1-P1´-P2´-P3´
Asp is required in P1
Synthetic Substrate
acetyl-Tyr-Val-Ala-Asp-amc
ac-YVAD-amc
ICE is a cysteine ICE is a cysteine proteinaseproteinase
It is inactivated by –SH blocking reagentsIt is inactivated by –SH blocking reagents 1414C-iodoacetate is incorporated into the 20 C-iodoacetate is incorporated into the 20
kDa subunitkDa subunit The enzyme can be potently inhibited by a The enzyme can be potently inhibited by a
peptide aldehydepeptide aldehydeH
OH
ES C RRCHO + E-SH
Thornberry et al, Nature. 1992 Apr 30;356(6372):768-774.
Thornberry et al, Nature. 1992 Apr 30;356(6372):768-774.
AIF (apoptosis – inducing factor) and AIF (apoptosis – inducing factor) and endonuclease G – involved in DNA endonuclease G – involved in DNA fragmentationfragmentation
Omi/HtrA2 (a serine proteinase) – Omi/HtrA2 (a serine proteinase) – interacts with IAPinteracts with IAP
Finkel, Science. 2001 Apr 27;292(5517):624-626.
Center stage in apoptosis· In this view, numerous cell-death stimuli work through the mitochondrion. They cause pro-apoptotic members of the BCL-2 family, such as BAX and BAK, to either open new pores or modify existing channels in the mitochondrial membrane, releasing cytochrome c and other proteins that lead to caspase activation and cell death. BCL-2 itself, which is antiapoptotic, somehow blocks the pore or channel opening.ILLUSTRATION: C. SLAYDEN
Adams and Cory, Science. 1998 Aug 28;281(5381):1322-1326.
Figure 1. Pathways to cell death in C. elegans and mammals. The CED-9/Bcl-2 family integrates positive and negative signals and arbitrates whether apoptosis should occur; activation of CED-4/Apaf-1 commits to apoptosis, and CED-3/caspases mediate the death process. In mammalian cells, the Bcl-2 family rules on signals from diverse cytotoxic stimuli (for example, cytokine deprivation and exposure to glucocorticoids, DNA damage, or staurosporine). However, the signal induced by engagement of the "death receptor" CD95 proceeds primarily through the adaptor FADD, which directly activates caspase-8 and largely bypasses the Bcl-2 family (see text).