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Olson MR, Holley CL, Yoo SJ, Huh JR, Hay BA, Kornbluth S. Reaper is regulated by IAP-mediated ubiquitination. J Biol Chem 2003; 278:4028-34. [PMID: 12446669 DOI: 10.1074/jbc.m209734200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In most cases, apoptotic cell death culminates in the activation of the caspase family of cysteine proteases, leading to the orderly dismantling and elimination of the cell. The IAPs (inhibitors of apoptosis) comprise a family of proteins that oppose caspases and thus act to raise the apoptotic threshold. Disruption of IAP-mediated caspase inhibition has been shown to be an important activity for pro-apoptotic proteins in Drosophila (Reaper, HID, and Grim) and in mammalian cells (Smac/DIABLO and Omi/HtrA2). In addition, in the case of the fly, these proteins are able to stimulate the ubiquitination and degradation of IAPs by a mechanism involving the ubiquitin ligase activity of the IAP itself. In this report, we show that the Drosophila RHG proteins (Reaper, HID, and Grim) are themselves substrates for IAP-mediated ubiquitination. This ubiquitination of Reaper requires IAP ubiquitin-ligase activity and a stable interaction between Reaper and the IAP. Additionally, degradation of Reaper can be blocked by mutating its potential ubiquitination sites. Most importantly, we also show that regulation of Reaper by ubiquitination is a significant factor in determining its biological activity. These data demonstrate a novel function for IAPs and suggest that IAPs and Reaper-like proteins mutually control each other's abundance.
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Affiliation(s)
- Michael R Olson
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710, USA
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52
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Varghese J, Sade H, Vandenabeele P, Sarin A. Head involution defective (Hid)-triggered apoptosis requires caspase-8 but not FADD (Fas-associated death domain) and is regulated by Erk in mammalian cells. J Biol Chem 2002; 277:35097-104. [PMID: 12122017 DOI: 10.1074/jbc.m206445200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The molecular machinery of apoptosis is evolutionarily conserved with some exceptions. One such example is the Drosophila proapoptotic gene Head involution defective (Hid), whose mammalian homologue is not known. Hid is apoptotic to mammalian cells, and we have examined the mechanism by which Hid induces death. We demonstrate for the first time a role for the extracellular signal-related kinase-1/2 (Erk-1/2) in the regulation of Hid function in mammalian cells. Bcl-2 and an inhibitor of caspase-9 blocked apoptosis, indicative of a role for the mitochondrion in this pathway, and we provide evidence for a role for caspase-8 in Hid-induced apoptosis. Thus, apoptosis was blocked by an inhibitor of caspase-8, deletion of caspase-8 rendered cells resistant to Hid-induced apoptosis, and Hid associated with caspase-8 in cell lysates. The Fas-associated death domain (FADD) was dispensable for the apoptotic function of Hid, indicating that Hid does not require extracellular death receptor signaling for the activation of caspase-8. In activated T cells, the cytokine interleukin-2 blocked caspase-8 processing and apoptosis, suggesting that survival cues from trophic factors may target a Hid-like intermediate present in mammalian cells. Thus, this study shows that Hid engages with conserved components of cellular death machinery and suggests that apoptotic paradigms characterized by FADD-independent activation of caspase-8 may involve a Hid-like molecule in mammalian cells.
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Affiliation(s)
- Jishy Varghese
- National Centre for Biological Sciences, UAS-GKVK Campus, Bangalore 560065, Karnataka, India
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53
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Brun S, Rincheval V, Gaumer S, Mignotte B, Guenal I. reaper and bax initiate two different apoptotic pathways affecting mitochondria and antagonized by bcl-2 in Drosophila. Oncogene 2002; 21:6458-70. [PMID: 12226749 DOI: 10.1038/sj.onc.1205839] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2002] [Revised: 06/07/2002] [Accepted: 06/28/2002] [Indexed: 11/08/2022]
Abstract
bcl-2 was the first regulator of apoptosis shown to be involved in oncogenesis. Subsequent studies in mammals, in the nematode and in Drosophila revealed wide evolutionary conservation of the regulation of apoptosis. Although dbok/debcl, a member of the bcl-2 gene family described in Drosophila, shows pro-apoptotic activities, no anti-apoptotic bcl-2 family gene has been studied in Drosophila. We have previously reported that the human anti-apoptotic gene bcl-2 is functional in Drosophila, suggesting that the fruit fly shares regulatory mechanisms with vertebrates and the nematode, involving anti-apoptotic members of the bcl-2 family. We now report that bcl-2 suppresses rpr-induced apoptosis in Drosophila. Additionally, we have compared features of bax- and rpr-induced apoptosis. Flow cytometry analysis of wing disc cells demonstrate that both killers trigger mitochondrial defects. Interestingly, bcl-2 suppresses both bax- and rpr-induced mitochondrial defects while the caspase-inhibitor p35 is specific to the rpr pathway. Finally, we show that the inhibition of apoptosis by bcl-2 is associated with the down-regulation of rpr expression.
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Affiliation(s)
- Sylvain Brun
- Laboratoire de Génétique et Biologie Cellulaire, CNRS UPRES-A 8087, et Laboratoire de Génétique Moléculaire et Physiologie de l'EPHE, Université de Versailles-St Quentin en Yvelines, 45 avenue des Etats-Unis, F-78035 Versailles cedex, France
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54
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Clavería C, Caminero E, Martínez-A C, Campuzano S, Torres M. GH3, a novel proapoptotic domain in Drosophila Grim, promotes a mitochondrial death pathway. EMBO J 2002; 21:3327-36. [PMID: 12093734 PMCID: PMC126101 DOI: 10.1093/emboj/cdf354] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Grim encodes a protein required for programmed cell death in Drosophila. The Grim N-terminus induces apoptosis by disrupting IAP blockage of caspases; however, N-terminally-deleted Grim retains pro apoptotic activity. We describe GH3, a 15 amino acid internal Grim domain absolutely required for its proapoptotic activity and sufficient to induce cell death when fused to heterologous carrier proteins. A GH3 homology region is present in the Drosophila proapoptotic proteins Reaper and Sickle. The GH3 domain and the homologous regions in Reaper and Sickle are predicted to be structured as amphipathic alpha-helixes. During apoptosis induction, Grim colocalizes with mitochondria and cytochrome c in a GH3-dependent but N-terminal- and caspase activity-independent manner. When Grim is overexpressed in vivo, both the N-terminal and the GH3 domains are equally necessary, and cooperate for apoptosis induction. The N-terminal and GH3 Grim domains thus activate independent apoptotic pathways that synergize to induce programmed cell death efficiently.
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Affiliation(s)
- Cristina Clavería
- Departamento de Inmunología y Oncología, Centro Nacional de Biotecnología, CSIC-UAM, Campus de Cantoblanco, E-28049 Madrid, Spain
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55
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Li X, Scuderi A, Letsou A, Virshup DM. B56-associated protein phosphatase 2A is required for survival and protects from apoptosis in Drosophila melanogaster. Mol Cell Biol 2002; 22:3674-84. [PMID: 11997504 PMCID: PMC133809 DOI: 10.1128/mcb.22.11.3674-3684.2002] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2002] [Revised: 02/18/2002] [Accepted: 02/20/2002] [Indexed: 01/11/2023] Open
Abstract
Protein phosphorylation and specific protein kinases can initiate signal transduction pathways leading to programmed cell death. The specific protein phosphatases regulating apoptosis have been more elusive. Using double-stranded RNA-mediated interference (RNAi), the role of protein phosphatase 2A (PP2A) in cellular signaling was investigated. Knockdown of A or C subunits individually or of combined B subunits led to concurrent loss of nontargeted PP2A subunits, suggesting that PP2A is an obligate heterotrimer in vivo. Global knockdown of PP2A activity or specific loss of redundant B56 regulatory subunits caused cell death with the morphological and biochemical changes characteristic of apoptosis in cultured S2 cells. B56:PP2A-regulated apoptosis required caspases and the upstream regulators dark, reaper, head involution defective, and dp53. In Drosophila embryos, knockdown of B56-regulated PP2A activity resulted in apoptosis and failure of gastrulation, an effect that was blocked by concurrent RNAi of the caspase DRICE: B56-regulated PP2A activity appears to be required upstream of dp53 to maintain a critical proapoptotic substrate in a dephosphorylated, inactive state, thereby preventing apoptosis in Drosophila S2 cells.
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Affiliation(s)
- Xinghai Li
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84112-5550, USA
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56
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Gorski S, Marra M. Programmed cell death takes flight: genetic and genomic approaches to gene discovery in Drosophila. Physiol Genomics 2002; 9:59-69. [PMID: 12006672 DOI: 10.1152/physiolgenomics.00114.2001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Programmed cell death (PCD) is an essential and wide-spread physiological process that results in the elimination of cells. Genes required to carry out this process have been identified, and many of these remain the subjects of intense investigation. Here, we describe PCD, its functions, and some of the consequences when it goes awry. We review PCD in the model system, the fruit fly, Drosophila melanogaster, with a particular emphasis on cell death gene discovery resulting from both genetics and genomics-based approaches.
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Affiliation(s)
- S Gorski
- Genome Sequence Centre, British Columbia Cancer Agency, Vancouver, British Columbia, Canada V5Z 4E6.
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57
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Abstract
The molecular mechanisms of apoptosis are highly conserved throughout evolution. The homologs of genes essential for apoptosis in Caenorhabditis elegans and Drosophila melanogaster have been shown to be important for apoptosis in mammalian systems. Although a homologue for CED-4/apoptotic protease-activating factor (Apaf)-1 has been described in Drosophila, its exact function and the role of the mitochondrial pathway in its activation remain unclear. Here, we used the technique of RNA interference to dissect apoptotic signaling pathways in Drosophila cells. Inhibition of the Drosophila CED-4/Apaf-1-related killer (ARK) homologue resulted in pronounced inhibition of stress-induced apoptosis, whereas loss of ARK did not protect the cells from Reaper- or Grim-induced cell death. Reduction of DIAP1 induced rapid apoptosis in these cells, whereas the inhibition of DIAP2 expression did not but resulted in increased sensitivity to stress-induced apoptosis; apoptosis in both cases was prevented by inhibition of ARK expression. Cells in which cytochrome c expression was decreased underwent apoptosis induced by stress stimuli, Reaper or Grim. These results demonstrate the central role of ARK in stress-induced apoptosis, which appears to act independently of cytochrome c. Apoptosis induced by Reaper or Grim can proceed via a distinct pathway, independent of ARK.
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Affiliation(s)
- Katja C Zimmermann
- Division of Cellular Immunology, La Jolla Institute for Allergy and Immunology, San Diego, California 92121, USA
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58
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Peterson C, Carney GE, Taylor BJ, White K. reaper is required for neuroblast apoptosis during Drosophila development. Development 2002; 129:1467-76. [PMID: 11880355 DOI: 10.1242/dev.129.6.1467] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Developmentally regulated apoptosis in Drosophila requires the activity of the reaper (rpr), grim and head involution defective (hid) genes. The expression of these genes is differentially regulated, suggesting that there are distinct requirements for their proapoptotic activity in response to diverse developmental and environmental inputs. To examine this hypothesis, a mutation that removes the rpr gene was generated. In flies that lack rpr function, most developmental apoptosis was unaffected. However, the central nervous systems of rpr null flies were very enlarged. This was due to the inappropriate survival of both larval neurons and neuroblasts. Importantly, neuroblasts rescued from apoptosis remained functional, continuing to proliferate and generating many extra neurons. Males mutant for rpr exhibited behavioral defects resulting in sterility. Although both the ecdysone hormone receptor complex and p53 directly regulate rpr transcription, rpr was found to play a limited role in inducing apoptosis in response to either of these signals.
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Affiliation(s)
- Christian Peterson
- CBRC, Massachusetts General Hospital/Harvard Medical School, Building 149, 13 Street, Charlestown, MA 02129, USA
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59
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Bergmann A, Tugentman M, Shilo BZ, Steller H. Regulation of cell number by MAPK-dependent control of apoptosis: a mechanism for trophic survival signaling. Dev Cell 2002; 2:159-70. [PMID: 11832242 DOI: 10.1016/s1534-5807(02)00116-8] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Trophic mechanisms in which neighboring cells mutually control their survival by secreting extracellular factors play an important role in determining cell number. However, how trophic signaling suppresses cell death is still poorly understood. We now show that the survival of a subset of midline glia cells in Drosophila depends upon direct suppression of the proapoptotic protein HID via the EGF receptor/RAS/MAPK pathway. The TGFalpha-like ligand SPITZ is activated in the neurons, and glial cells compete for limited amounts of secreted SPITZ to survive. In midline glia that fail to activate the EGFR pathway, HID induces apoptosis by blocking a caspase inhibitor, Diap1. Therefore, a direct pathway linking a specific extracellular survival factor with a caspase-based death program has been established.
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Affiliation(s)
- Andreas Bergmann
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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60
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Srinivasula SM, Datta P, Kobayashi M, Wu JW, Fujioka M, Hegde R, Zhang Z, Mukattash R, Fernandes-Alnemri T, Shi Y, Jaynes JB, Alnemri ES. sickle, a novel Drosophila death gene in the reaper/hid/grim region, encodes an IAP-inhibitory protein. Curr Biol 2002; 12:125-30. [PMID: 11818063 PMCID: PMC2743937 DOI: 10.1016/s0960-9822(01)00657-1] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inhibitors of apoptosis proteins (IAPs) interact with caspases and inhibit their protease activity, whereas the IAP-inhibitory proteins Smac/DIABLO in mammals and Reaper, Hid, and Grim in flies relieve IAP-mediated inhibition to induce cell death. Here we describe the functional characterization of the novel Drosophila cell death protein Sickle (Skl), which binds to IAPs and neutralizes their apoptotic inhibitory activity. Skl exhibits no sequence homology to Reaper, Hid, Grim, or Smac/DIABLO, except within the 4 residue N-terminal IAP binding motif. Skl interacts with Drosophila and mammalian IAPs and can promote caspase activation in the presence of IAPs. Consistent with these findings, expression of Skl in Drosophila and mammalian cell lines or in Drosophila embryos induces apoptosis. Skl can also synergize with Grim to induce cell death in the Drosophila eye imaginal disc. Based on biochemical and structural data, the N terminus of Skl, like that of the mammalian Smac/DIABLO, is absolutely required for its apoptotic and caspase-promoting activities and its ability to interact with IAPs. These findings point to conservation in the structure and function of the IAP-inhibitory proteins across species and suggest the existence of other family members.
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Affiliation(s)
- Srinivasa M. Srinivasula
- The Center for Apoptosis Research and Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Pinaki Datta
- The Center for Apoptosis Research and Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Masatomo Kobayashi
- The Center for Apoptosis Research and Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Jia-Wei Wu
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, New Jersey 08544
| | - Miki Fujioka
- The Center for Apoptosis Research and Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Ramesh Hegde
- The Center for Apoptosis Research and Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - ZhiJia Zhang
- The Center for Apoptosis Research and Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Rula Mukattash
- The Center for Apoptosis Research and Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Teresa Fernandes-Alnemri
- The Center for Apoptosis Research and Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Yigong Shi
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, New Jersey 08544
| | - James B. Jaynes
- The Center for Apoptosis Research and Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Emad S. Alnemri
- The Center for Apoptosis Research and Department of Microbiology and Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
- Correspondence:
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61
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Wu JW, Cocina AE, Chai J, Hay BA, Shi Y. Structural analysis of a functional DIAP1 fragment bound to grim and hid peptides. Mol Cell 2001; 8:95-104. [PMID: 11511363 DOI: 10.1016/s1097-2765(01)00282-9] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The inhibitor of apoptosis protein DIAP1 suppresses apoptosis in Drosophila, with the second BIR domain (BIR2) playing an important role. Three proteins, Hid, Grim, and Reaper, promote apoptosis, in part by binding to DIAP1 through their conserved N-terminal sequences. The crystal structures of DIAP1-BIR2 by itself and in complex with the N-terminal peptides from Hid and Grim reveal that these peptides bind a surface groove on DIAP1, with the first four amino acids mimicking the binding of the Smac tetrapeptide to XIAP. The next 3 residues also contribute to binding through hydrophobic interactions. Interestingly, peptide binding induces the formation of an additional alpha helix in DIAP1. Our study reveals the structural conservation and diversity necessary for the binding of IAPs by the Drosophila Hid/Grim/Reaper and the mammalian Smac proteins.
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Affiliation(s)
- J W Wu
- Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ 08544, USA
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62
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Nakano Y, Fujitani K, Kurihara J, Ragan J, Usui-Aoki K, Shimoda L, Lukacsovich T, Suzuki K, Sezaki M, Sano Y, Ueda R, Awano W, Kaneda M, Umeda M, Yamamoto D. Mutations in the novel membrane protein spinster interfere with programmed cell death and cause neural degeneration in Drosophila melanogaster. Mol Cell Biol 2001; 21:3775-88. [PMID: 11340170 PMCID: PMC87027 DOI: 10.1128/mcb.21.11.3775-3788.2001] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2001] [Accepted: 03/09/2001] [Indexed: 11/20/2022] Open
Abstract
Mutations in the spin gene are characterized by an extraordinarily strong rejection behavior of female flies in response to male courtship. They are also accompanied by decreases in the viability, adult life span, and oviposition rate of the flies. In spin mutants, some oocytes and adult neural cells undergo degeneration, which is preceded by reductions in programmed cell death of nurse cells in ovaries and of neurons in the pupal nervous system, respectively. The central nervous system (CNS) of spin mutant flies accumulates autofluorescent lipopigments with characteristics similar to those of lipofuscin. The spin locus generates at least five different transcripts, with only two of these being able to rescue the spin behavioral phenotype; each encodes a protein with multiple membrane-spanning domains that are expressed in both the surface glial cells in the CNS and the follicle cells in the ovaries. Orthologs of the spin gene have also been identified in a number of species from nematodes to humans. Analysis of the spin mutant will give us new insights into neurodegenerative diseases and aging.
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Affiliation(s)
- Y Nakano
- ERATO Yamamoto Behavior Genes Project, Japan Science and Technology Corporation at Mitsubishi Kasei Institute of Life Sciences, Machida, Tokyo 194-8511, Japan
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63
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Abstract
Apoptosis and autophagy are morphologically distinct forms of programmed cell death. While autophagy occurs during the development of diverse organisms and has been implicated in tumorigenesis, little is known about the molecular mechanisms that regulate this type of cell death. Here we show that steroid-activated programmed cell death of Drosophila salivary glands occurs by autophagy. Expression of p35 prevents DNA fragmentation and partially inhibits changes in the cytosol and plasma membranes of dying salivary glands, suggesting that caspases are involved in autophagy. The steroid-regulated BR-C, E74A and E93 genes are required for salivary gland cell death. BR-C and E74A mutant salivary glands exhibit vacuole and plasma membrane breakdown, but E93 mutant salivary glands fail to exhibit these changes, indicating that E93 regulates early autophagic events. Expression of E93 in embryos is sufficient to induce cell death with many characteristics of apoptosis, but requires the H99 genetic interval that contains the rpr, hid and grim proapoptotic genes to induce nuclear changes diagnostic of apoptosis. In contrast, E93 expression is sufficient to induce the removal of cells by phagocytes in the absence of the H99 genes. These studies indicate that apoptosis and autophagy utilize some common regulatory mechanisms.
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Affiliation(s)
- C Y Lee
- Center for Agricultural Biotechnology, University of Maryland Biotechnology Institute, College Park, Maryland 20742, USA
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64
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Wing JP, Schwartz LM, Nambu JR. The RHG motifs of Drosophila Reaper and Grim are important for their distinct cell death-inducing abilities. Mech Dev 2001; 102:193-203. [PMID: 11287192 DOI: 10.1016/s0925-4773(01)00316-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Reaper, Hid, and Grim are three Drosophila cell death activators that each contain a conserved NH(2)-terminal Reaper, Hid, Grim (RHG) motif. We have analyzed the importance of the RHG motifs in Reaper and Grim for their different abilities to activate cell death during development. Analysis of chimeric R/Grim and G/Reaper proteins indicated that the Reaper and Grim RHG motifs are functionally distinct and help to determine specific cell death activation properties. A truncated GrimC protein lacking the RHG motif retained an ability to induce cell death, and unlike Grim, R/Grim, or G/Reaper, its actions were not efficiently blocked by the cell death inhibitors, Diap1, Diap2, p35, or a dominant/negative Dronc caspase. Finally, we identified a second region of sequence similarity in Reaper, Hid, and Grim, that may be important for shared RHG motif-independent activities.
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Affiliation(s)
- J P Wing
- Molecular and Cellular Biology Program, University of Massachusetts at Amherst, 01003, USA
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65
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Ekert PG, Silke J, Hawkins CJ, Verhagen AM, Vaux DL. DIABLO promotes apoptosis by removing MIHA/XIAP from processed caspase 9. J Cell Biol 2001; 152:483-90. [PMID: 11157976 PMCID: PMC2195997 DOI: 10.1083/jcb.152.3.483] [Citation(s) in RCA: 146] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
MIHA is an inhibitor of apoptosis protein (IAP) that can inhibit cell death by direct interaction with caspases, the effector proteases of apoptosis. DIABLO is a mammalian protein that can bind to IAPs and antagonize their antiapoptotic effect, a function analogous to that of the proapoptotic Drosophila molecules, Grim, Reaper, and HID. Here, we show that after UV radiation, MIHA prevented apoptosis by inhibiting caspase 9 and caspase 3 activation. Unlike Bcl-2, MIHA functioned after release of cytochrome c and DIABLO from the mitochondria and was able to bind to both processed caspase 9 and processed caspase 3 to prevent feedback activation of their zymogen forms. Once released into the cytosol, DIABLO bound to MIHA and disrupted its association with processed caspase 9, thereby allowing caspase 9 to activate caspase 3, resulting in apoptosis.
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Affiliation(s)
- Paul G. Ekert
- The Walter and Eliza Hall Institute, The Royal Melbourne Hospital, Victoria 3050, Australia
- Murdoch Children's Research Institute, Royal Children's Hospital, Parkville 3052, Australia
| | - John Silke
- The Walter and Eliza Hall Institute, The Royal Melbourne Hospital, Victoria 3050, Australia
| | - Christine J. Hawkins
- Department of Haematology and Oncology, Royal Children's Hospital, Parkville 3052, Australia
| | - Anne M. Verhagen
- The Walter and Eliza Hall Institute, The Royal Melbourne Hospital, Victoria 3050, Australia
| | - David L. Vaux
- The Walter and Eliza Hall Institute, The Royal Melbourne Hospital, Victoria 3050, Australia
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66
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Abstract
One of the near-to-invariant hallmarks of early apoptosis (programmed cell death) is mitochondrial membrane permeabilization (MMP). It appears that mitochondria fulfill a dual role during the apoptotic process. On the one hand, they integrate multiple different pro-apoptotic signal transducing cascades into a common pathway initiated by MMP. On the other hand, they coordinate the catabolic reactions accompanying late apoptosis by releasing soluble proteins that are normally sequestered within the intermembrane space. In a recent study, Li et al. described a nuclear transcription factor (Nur77/TR1/NGFI-B) that can translocate to mitochondrial membranes to induce MMP. Moreover, two groups identified a novel intermembrane protein (Smac/DIABLO) that specifically neutralizes the inhibitor of apoptosis (IAP) proteins, thereby facilitating the activation of caspases, a class of proteases activated during apoptosis. These findings refine our knowledge how MMP connects to the cellular suicide machinery.
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Affiliation(s)
- K F Ferri
- Centre National de la Recherche Scientifique, Institut Gustave Roussy, Villejuif, France
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67
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Abstract
Programmed cell death plays critical roles in a wide variety of physiological processes during fetal development and in adult tissues. In most cases, physiological cell death occurs by apoptosis as opposed to necrosis. Defects in apoptotic cell death regulation contribute to many diseases, including disorders where cell accumulation occurs (cancer, restenosis) or where cell loss ensues (stroke, heart failure, neurodegeneration, AIDS). In recent years, the molecular machinery responsible for apoptosis has been elucidated, revealing a family of intracellular proteases, the caspases, which are responsible directly or indirectly for the morphological and biochemical changes that characterize the phenomenon of apoptosis. Diverse regulators of the caspases have also been discovered, including activators and inhibitors of these cell death proteases. Inputs from signal transduction pathways into the core of the cell death machinery have also been identified, demonstrating ways of linking environmental stimuli to cell death responses or cell survival maintenance. Knowledge of the molecular mechanisms of apoptosis is providing insights into the causes of multiple pathologies where aberrant cell death regulation occurs and is beginning to provide new approaches to the treatment of human diseases.
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Affiliation(s)
- J C Reed
- Burnham Institute, La Jolla, California 92037, USA.
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68
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Bangs P, Franc N, White K. Molecular mechanisms of cell death and phagocytosis in Drosophila. Cell Death Differ 2000; 7:1027-34. [PMID: 11139274 DOI: 10.1038/sj.cdd.4400754] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The genetic tools available in Drosophila have facilitated our understanding of how apoptosis is regulated and executed in the context of the developing organism. All embryonic apoptosis is initiated by the activity of three genes, rpr, grim and hid. Each of these genes is independently regulated, allowing developmental apoptosis to be finely controlled. These initiators in turn activate the core apoptotic machinery, including the caspases. Drosophila counterparts to other conserved components of the apoptotic machinery have been recently identified, and we discuss how these may be integrated into the process of normal developmentally regulated cell death. We also outline the role that phagocytosis plays in the final stages of apoptosis and consider the molecular mechanisms guiding the elimination of apoptotic corpses.
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Affiliation(s)
- P Bangs
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
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69
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Abstract
Programmed cell death plays an important role in maintaining homeostasis during animal development, and has been conserved in animals as different as nematodes and humans. Recent studies of Drosophila have provided valuable information toward our understanding of genetic regulation of death. Different signals trigger the novel death regulators rpr, hid, and grim, that utilize the evolutionarily conserved iap and ark genes to modulate caspase function. Subsequent removal of dying cells also appears to be accomplished by conserved mechanisms. The similarity between Drosophila and human in cell death signaling pathways illustrate the promise of fruit flies as a model system to elucidate the mechanisms underlying regulation of programmed cell death.
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Affiliation(s)
- C Y Lee
- Center for Agricultural Biotechnology, University of Maryland Biotechnology Institute, Department of Biology, University of Maryland, College Park 20742, USA
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70
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Gaumer S, Guénal I, Brun S, Théodore L, Mignotte B. Bcl-2 and Bax mammalian regulators of apoptosis are functional in Drosophila. Cell Death Differ 2000; 7:804-14. [PMID: 11042675 DOI: 10.1038/sj.cdd.4400714] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Studies of apoptosis in C. elegans have allowed the identification of three genes, ced-3, ced-4 and ced-9. Their products constitute the components of an induction pathway of apoptosis conserved in the nematode and mammals. In Drosophila, homologues have been found for CED-3, CED-4 and CED-9. CED-9 belongs to the Bcl-2 family which includes negative (Bcl-2) and positive (Bax) regulators of apoptosis. The recently discovered Bcl-2 family member named Drob-1 acts as a positive regulator of cell death. To address whether a Bcl-2 anti-apoptotic pathway exists in the fly, we studied the effects of expressing the mammalian genes bcl-2 in Drosophila. In embryos, expression of bcl-2 inhibits developmental and X-ray-induced apoptosis. Expressing bcl-2 or the pro-apoptotic mammalian bax in the developing eye and wing alters these structures, bcl-2 increasing the number of cells, while bax reduces the number of cells. In addition, the functional interaction between Bcl-2 and Bax is conserved. These results indicate that factors necessary for the activity of bcl-2 and bax are present in Drosophila. Therefore, a Bcl-2 pathway for inhibition of cell death may exist in the fly.
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Affiliation(s)
- S Gaumer
- CNRS - UPRES-A 8087, Université de Versailles/Saint-Quentin, 78035 Versailles cedex, France
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71
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Affiliation(s)
- S Bialik
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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72
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Cox RT, McEwen DG, Myster DL, Duronio RJ, Loureiro J, Peifer M. A screen for mutations that suppress the phenotype of Drosophila armadillo, the beta-catenin homolog. Genetics 2000; 155:1725-40. [PMID: 10924470 PMCID: PMC1461219 DOI: 10.1093/genetics/155.4.1725] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
During development signaling pathways coordinate cell fates and regulate the choice between cell survival or programmed cell death. The well-conserved Wingless/Wnt pathway is required for many developmental decisions in all animals. One transducer of the Wingless/Wnt signal is Armadillo/beta-catenin. Drosophila Armadillo not only transduces Wingless signal, but also acts in cell-cell adhesion via its role in the epithelial adherens junction. While many components of both the Wingless/Wnt signaling pathway and adherens junctions are known, both processes are complex, suggesting that unknown components influence signaling and junctions. We carried out a genetic modifier screen to identify some of these components by screening for mutations that can suppress the armadillo mutant phenotype. We identified 12 regions of the genome that have this property. From these regions and from additional candidate genes tested we identified four genes that suppress arm: dTCF, puckered, head involution defective (hid), and Dpresenilin. We further investigated the interaction with hid, a known regulator of programmed cell death. Our data suggest that Wg signaling modulates Hid activity and that Hid regulates programmed cell death in a dose-sensitive fashion.
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Affiliation(s)
- R T Cox
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280, USA
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73
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Lee CY, Wendel DP, Reid P, Lam G, Thummel CS, Baehrecke EH. E93 directs steroid-triggered programmed cell death in Drosophila. Mol Cell 2000; 6:433-43. [PMID: 10983989 DOI: 10.1016/s1097-2765(00)00042-3] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Steroid hormones coordinate multiple cellular changes, yet the mechanisms by which these systemic signals are refined into stage- and tissue-specific responses remain poorly understood. Here we show that the Drosophila E93 gene determines the nature of a steroid-induced biological response. E93 mutants possess larval salivary glands that fail to undergo steroid-triggered programmed cell death, and E93 is expressed in cells immediately before the onset of death. E93 protein is bound to the sites of steroid-regulated and cell death genes on polytene chromosomes, and the expression of these genes is defective in E93 mutants. Furthermore, expression of E93 is sufficient to induce programmed cell death. We propose that the steroid induction of E93 determines a programmed cell death response during development.
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Affiliation(s)
- C Y Lee
- Center for Agricultural Biotechnology, University of Maryland Biotechnology Institute, College Park 20742, USA
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74
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Heinrich JC, Scott MJ. A repressible female-specific lethal genetic system for making transgenic insect strains suitable for a sterile-release program. Proc Natl Acad Sci U S A 2000; 97:8229-32. [PMID: 10890889 PMCID: PMC26929 DOI: 10.1073/pnas.140142697] [Citation(s) in RCA: 176] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2000] [Indexed: 11/18/2022] Open
Abstract
We have developed a tetracycline-repressible female-specific lethal genetic system in the vinegar fly Drosophila melanogaster. One component of the system is the tetracycline-controlled transactivator gene under the control of the fat body and female-specific transcription enhancer from the yolk protein 1 gene. The other component consists of the proapoptotic gene hid under the control of a tetracycline-responsive element. Males and females of a strain carrying both components are viable on medium supplemented with tetracycline, but only males survive on normal medium. A strain with such properties would be ideal for a sterile-insect release program, which is most effective when only males are released in the field.
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Affiliation(s)
- J C Heinrich
- Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand
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75
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Du C, Fang M, Li Y, Li L, Wang X. Smac, a mitochondrial protein that promotes cytochrome c-dependent caspase activation by eliminating IAP inhibition. Cell 2000; 102:33-42. [PMID: 10929711 DOI: 10.1016/s0092-8674(00)00008-8] [Citation(s) in RCA: 2395] [Impact Index Per Article: 99.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We report here the identification of a novel protein, Smac, which promotes caspase activation in the cytochrome c/Apaf-1/caspase-9 pathway. Smac promotes caspase-9 activation by binding to inhibitor of apoptosis proteins, IAPs, and removing their inhibitory activity. Smac is normally a mitochondrial protein but is released into the cytosol when cells undergo apoptosis. Mitochondrial import and cleavage of its signal peptide are required for Smac to gain its apoptotic activity. Overexpression of Smac increases cells' sensitivity to apoptotic stimuli. Smac is the second mitochondrial protein, along with cytochrome c, that promotes apoptosis by activating caspases.
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Affiliation(s)
- C Du
- Howard Hughes Medical Institute and Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 75235, USA
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76
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Abstract
The development of the Drosophila embryo into an adult fly is a process that integrates cell proliferation and differentiation with programmed cell death, or apoptosis. Apoptosis is an evolutionarily conserved process that is controlled in the developing fly by the products of the genes reaper, grim, and hid. We discuss the role of programmed cell death in the establishment and maintenance of correct patterning in the embryo, and examine the coordination of apoptosis with the hormonally controlled degeneration of larval tissues during metamorphosis. Finally, we address the architecture of the adult eye as an example of how programmed cell death plays a key role in the development of many adult structures.
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Affiliation(s)
- P Bangs
- Cutaneous Biology Research Center, Massachusetts General Hospital, Harvard Medical School, Charlestown 02129, USA
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77
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Li F, Flanary PL, Altieri DC, Dohlman HG. Cell division regulation by BIR1, a member of the inhibitor of apoptosis family in yeast. J Biol Chem 2000; 275:6707-11. [PMID: 10702224 DOI: 10.1074/jbc.275.10.6707] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The inhibitor of apoptosis (IAP) gene family comprises molecules that block the activity of pro-apoptotic caspase proteases. Paradoxically, yeasts contain IAP proteins but no caspases and no apoptotic program. To determine the function of these proteins in vivo, we disrupted the BIR1 gene, encoding the only known IAP in yeast Saccharomyces cerevisiae. Sporulation of heterozygous diploids yielded no viable mutant haploids, indicating that BIR1 is an essential gene. By flow cytometry, some heterozygous mutants were polyploid accumulating >4 N DNA content. These cells exhibited a 20-40% reduction in growth rate, which was rescued by plasmid-borne over-expression of BIR1 but not by its human counterpart, survivin. Deletion analysis revealed that the N-terminal domain of Bir1, containing the conserved baculovirus IAP repeat, was able to partially complement the cell growth defect caused by BIR1 deletion. Moreover, the full-length and truncated forms of Bir1 accelerated cell division in wild-type cells. Finally, BIR1 heterozygous mutants exhibited grossly altered cell morphology with misshapen or abnormally long buds connected to an unusually large mother cell. These findings identify a novel function of IAP proteins in the pleiotropic control of cell division, in addition to their role in the suppression of apoptosis.
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Affiliation(s)
- F Li
- Department of Pathology, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA
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78
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Colussi PA, Quinn LM, Huang DC, Coombe M, Read SH, Richardson H, Kumar S. Debcl, a proapoptotic Bcl-2 homologue, is a component of the Drosophila melanogaster cell death machinery. J Cell Biol 2000; 148:703-14. [PMID: 10684252 PMCID: PMC2169366 DOI: 10.1083/jcb.148.4.703] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bcl-2 family of proteins are key regulators of apoptosis. Both proapoptotic and antiapoptotic members of this family are found in mammalian cells, but no such proteins have been described in insects. Here, we report the identification and characterization of Debcl, the first Bcl-2 homologue in Drosophila melanogaster. Structurally, Debcl is similar to Bax-like proapoptotic Bcl-2 family members. Ectopic expression of Debcl in cultured cells and in transgenic flies causes apoptosis, which is inhibited by coexpression of the baculovirus caspase inhibitor P35, indicating that Debcl is a proapoptotic protein that functions in a caspase-dependent manner. debcl expression correlates with developmental cell death in specific Drosophila tissues. We also show that debcl genetically interacts with diap1 and dark, and that debcl-mediated apoptosis is not affected by gene dosage of rpr, hid, and grim. Biochemically, Debcl can interact with several mammalian and viral prosurvival Bcl-2 family members, but not with the proapoptotic members, suggesting that it may regulate apoptosis by antagonizing prosurvival Bcl-2 proteins. RNA interference studies indicate that Debcl is required for developmental apoptosis in Drosophila embryos. These results suggest that the main components of the mammalian apoptosis machinery are conserved in insects.
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MESH Headings
- Amino Acid Sequence
- Animals
- Animals, Genetically Modified
- Apoptosis/drug effects
- Apoptosis/genetics
- Apoptosis/physiology
- Caspase Inhibitors
- Caspases/metabolism
- Cell Survival/drug effects
- Cells, Cultured
- Cloning, Molecular
- Drosophila Proteins
- Drosophila melanogaster/cytology
- Drosophila melanogaster/embryology
- Drosophila melanogaster/genetics
- Drosophila melanogaster/metabolism
- Epistasis, Genetic
- Gene Expression
- Genes, Insect/genetics
- Inhibitor of Apoptosis Proteins
- Insect Proteins/genetics
- Molecular Sequence Data
- Mutation/genetics
- Protein Binding
- Protein Structure, Tertiary
- Proteins/genetics
- Proto-Oncogene Proteins c-bcl-2/chemistry
- Proto-Oncogene Proteins c-bcl-2/genetics
- Proto-Oncogene Proteins c-bcl-2/metabolism
- RNA, Double-Stranded/administration & dosage
- RNA, Double-Stranded/pharmacology
- RNA, Messenger/analysis
- RNA, Messenger/genetics
- Sequence Homology, Amino Acid
- Viral Proteins/genetics
- Viral Proteins/metabolism
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Affiliation(s)
- Paul A. Colussi
- The Hanson Centre for Cancer Research, Institute of Medical and Veterinary Science, Adelaide, SA 5000, Australia
| | - Leonie M. Quinn
- Department of Genetics, The University of Adelaide, Adelaide, SA 5001, Australia
| | - David C.S. Huang
- The Walter and Eliza Hall Institute of Medical Research, The Royal Melbourne Hospital, Melbourne, Vic 3050, Australia
| | - Michelle Coombe
- Department of Genetics, The University of Adelaide, Adelaide, SA 5001, Australia
| | - Stuart H. Read
- The Hanson Centre for Cancer Research, Institute of Medical and Veterinary Science, Adelaide, SA 5000, Australia
| | - Helena Richardson
- Department of Genetics, The University of Adelaide, Adelaide, SA 5001, Australia
| | - Sharad Kumar
- The Hanson Centre for Cancer Research, Institute of Medical and Veterinary Science, Adelaide, SA 5000, Australia
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79
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Goyal L, McCall K, Agapite J, Hartwieg E, Steller H. Induction of apoptosis by Drosophila reaper, hid and grim through inhibition of IAP function. EMBO J 2000; 19:589-97. [PMID: 10675328 PMCID: PMC305597 DOI: 10.1093/emboj/19.4.589] [Citation(s) in RCA: 367] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/1999] [Revised: 12/13/1999] [Accepted: 12/13/1999] [Indexed: 11/13/2022] Open
Abstract
Induction of apoptosis in Drosophila requires the activity of three closely linked genes, reaper, hid and grim. Here we show that the proteins encoded by reaper, hid and grim activate cell death by inhibiting the anti-apoptotic activity of the Drosophila IAP1 (diap1) protein. In a genetic modifier screen, both loss-of-function and gain-of-function alleles in the endogenous diap1 gene were obtained, and the mutant proteins were functionally and biochemically characterized. Gain-of-function mutations in diap1 strongly suppressed reaper-, hid- and grim-induced apoptosis. Sequence analysis of these alleles revealed that they were caused by single amino acid changes in the baculovirus IAP repeat domains of diap1, a domain implicated in binding REAPER, HID and GRIM. Significantly, the corresponding mutant DIAP1 proteins displayed greatly reduced binding of REAPER, HID and GRIM, indicating that REAPER, HID and GRIM kill by forming a complex with DIAP1. These data provide strong in vivo evidence for a previously published model of cell death regulation in Drosophila.
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Affiliation(s)
- L Goyal
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Departments of Biology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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80
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Jacotot E, Ravagnan L, Loeffler M, Ferri KF, Vieira HL, Zamzami N, Costantini P, Druillennec S, Hoebeke J, Briand JP, Irinopoulou T, Daugas E, Susin SA, Cointe D, Xie ZH, Reed JC, Roques BP, Kroemer G. The HIV-1 viral protein R induces apoptosis via a direct effect on the mitochondrial permeability transition pore. J Exp Med 2000; 191:33-46. [PMID: 10620603 PMCID: PMC2195797 DOI: 10.1084/jem.191.1.33] [Citation(s) in RCA: 340] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/1999] [Accepted: 10/15/1999] [Indexed: 01/28/2023] Open
Abstract
Viral protein R (Vpr) encoded by HIV-1 is a facultative inducer of apoptosis. When added to intact cells or purified mitochondria, micromolar and submicromolar doses of synthetic Vpr cause a rapid dissipation of the mitochondrial transmembrane potential (DeltaPsi(m)), as well as the mitochondrial release of apoptogenic proteins such as cytochrome c or apoptosis inducing factor. The same structural motifs relevant for cell killing are responsible for the mitochondriotoxic effects of Vpr. Both mitochondrial and cytotoxic Vpr effects are prevented by Bcl-2, an inhibitor of the permeability transition pore complex (PTPC). Coincubation of purified organelles revealed that nuclear apoptosis is only induced by Vpr when mitochondria are present yet can be abolished by PTPC inhibitors. Vpr favors the permeabilization of artificial membranes containing the purified PTPC or defined PTPC components such as the adenine nucleotide translocator (ANT) combined with Bax. Again, this effect is prevented by addition of recombinant Bcl-2. The Vpr COOH terminus binds purified ANT, as well as a molecular complex containing ANT and the voltage-dependent anion channel (VDAC), another PTPC component. Yeast strains lacking ANT or VDAC are less susceptible to Vpr-induced killing than control cells yet recover Vpr sensitivity when retransfected with yeast ANT or human VDAC. Hence, Vpr induces apoptosis via a direct effect on the mitochondrial PTPC.
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Affiliation(s)
- Etienne Jacotot
- Centre National de la Recherche Scientifique, F-94801 Villejuif, France
| | - Luigi Ravagnan
- Centre National de la Recherche Scientifique, F-94801 Villejuif, France
| | - Markus Loeffler
- Centre National de la Recherche Scientifique, F-94801 Villejuif, France
| | - Karine F. Ferri
- Centre National de la Recherche Scientifique, F-94801 Villejuif, France
| | | | - Naoufal Zamzami
- Centre National de la Recherche Scientifique, F-94801 Villejuif, France
| | - Paola Costantini
- Centre National de la Recherche Scientifique, F-94801 Villejuif, France
| | - Sabine Druillennec
- Unité de Pharmacochimie Moléculaire et Structurale, Institut National de la Santé et de Recherche Médicale (INSERM) U266, CNRS UMR 860, Université René Descartes (Paris V), 75006 Paris, France
| | - Johan Hoebeke
- Institut de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, 67084 Strasbourg, France
| | - Jean Paul Briand
- Institut de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, 67084 Strasbourg, France
| | | | - Eric Daugas
- Centre National de la Recherche Scientifique, F-94801 Villejuif, France
| | - Santos A. Susin
- Centre National de la Recherche Scientifique, F-94801 Villejuif, France
| | - Denis Cointe
- Laboratoire de Virologie et Immunologie, Hopital Antoine Beclère, 92141 Clamart, France
| | - Zhi Hua Xie
- The Burnham Institute, La Jolla, California 92037
| | - John C. Reed
- The Burnham Institute, La Jolla, California 92037
| | - Bernard P. Roques
- Unité de Pharmacochimie Moléculaire et Structurale, Institut National de la Santé et de Recherche Médicale (INSERM) U266, CNRS UMR 860, Université René Descartes (Paris V), 75006 Paris, France
| | - Guido Kroemer
- Centre National de la Recherche Scientifique, F-94801 Villejuif, France
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81
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82
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83
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84
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Abstract
Apoptosis research demonstrates that, even though the multitude of regulatory circuits controlling programmed cell death might diverge, core elements of the 'apoptotic engine' are widely conserved. Therefore, studies in less complex model systems, such as the nematode and the fly, should continue to have a profound impact on our understanding of the process. This review explores genes and molecules that control apoptosis in Drosophila. The death inducers Reaper, Grim and Hid relay signals, possibly through IAPs (inhibitor of apoptosis proteins) and Dark (an Apaf-1/Ced-4 homologue), to trigger caspase function. This animal model promises continued insights into the determinants of cell death in 'naturally occurring' and pathological contexts.
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Affiliation(s)
- J M Abrams
- Dept of Cell Biology, The University of Texas, Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235-9039, USA.
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85
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Zhou L, Song Z, Tittel J, Steller H. HAC-1, a Drosophila homolog of APAF-1 and CED-4 functions in developmental and radiation-induced apoptosis. Mol Cell 1999; 4:745-55. [PMID: 10619022 DOI: 10.1016/s1097-2765(00)80385-8] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We have identified a Drosophila homolog of Apaf-1 and ced-4, termed hac-1. Like mammalian APAF-1, HAC-1 can activate caspases in a dATP-dependent manner in vitro. During embryonic development, hac-1 is prominently expressed in regions where cells undergo natural death. Significantly, hac-1 transcription is also rapidly induced upon ionizing irradiation, similar to the proapoptotic gene reaper. Loss of hac-1 function causes reduced cell death, and reducing the dosage of hac-1 suppresses ectopic cell killing upon expression of the dcp-1 procaspase in the retina but has little effect on reaper, hid, and grim-mediated killing. Our data indicate that caspase activation and apoptosis in Drosophila are independently controlled by at least two distinct regulatory pathways that converge at the level of caspase activation.
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Affiliation(s)
- L Zhou
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA
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