51
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Niu H, Kozjak-Pavlovic V, Rudel T, Rikihisa Y. Anaplasma phagocytophilum Ats-1 is imported into host cell mitochondria and interferes with apoptosis induction. PLoS Pathog 2010; 6:e1000774. [PMID: 20174550 PMCID: PMC2824752 DOI: 10.1371/journal.ppat.1000774] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Accepted: 01/15/2010] [Indexed: 12/14/2022] Open
Abstract
Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis, infects human neutrophils and inhibits mitochondria-mediated apoptosis. Bacterial factors involved in this process are unknown. In the present study, we screened a genomic DNA library of A. phagocytophilum for effectors of the type IV secretion system by a bacterial two-hybrid system, using A. phagocytophilum VirD4 as bait. A hypothetical protein was identified as a putative effector, hereby named Anaplasmatranslocated substrate 1 (Ats-1). Using triple immunofluorescence labeling and Western blot analysis of infected cells, including human neutrophils, we determined that Ats-1 is abundantly expressed by A. phagocytophilum, translocated across the inclusion membrane, localized in the host cell mitochondria, and cleaved. Ectopically expressed Ats-1 targeted mitochondria in an N-terminal 17 residue-dependent manner, localized in matrix or at the inner membrane, and was cleaved as native protein, which required residues 55–57. In vitro-translated Ats-1 was imported in a receptor-dependent manner into isolated mitochondria. Ats-1 inhibited etoposide-induced cytochrome c release from mitochondria, PARP cleavage, and apoptosis in mammalian cells, as well as Bax-induced yeast apoptosis. Ats-1(55–57) had significantly reduced anti-apoptotic activity. Bax redistribution was inhibited in both etoposide-induced and Bax-induced apoptosis by Ats-1. Taken together, Ats-1 is the first example of a bacterial protein that traverses five membranes and prevents apoptosis at the mitochondria. Anaplasma phagocytophilum is the pathogen that causes human granulocytic anaplasmosis, an emerging infectious disease. As an obligate intracellular organism, this bacterium cannot reproduce outside of eukaryotic cells due to the loss of many genes that are present in free-living bacteria. Paradoxically, it specifically infects short-lived white blood cells that play critical roles in anti-microbial defense, by subverting a number of host innate immune responses including programmed cell death (apoptosis). A. phagocytophilum factors that are involved in this process are largely unknown. In this study, we first searched A. phagocytophilum proteins that are secreted by its specialized secretion system into eukaryotic cells. We found a protein of unknown function, here named Ats-1, which is abundantly produced by A. phagocytophilum and traverses five membranes to enter the mitochondria of human cells. Our further study showed that Ats-1 reduces the sensitivity of mitochondria to respond to apoptosis-inducing factors, leading to the inhibition of host cell apoptosis. Thus, present findings identified a bacterial protein that allows infected white blood cells to live longer to support bacterial growth. The absence of similarity of the sequence or the mode of action to any other known cell death suppressor suggests that Ats-1 defines a previously undescribed class of anti-apoptotic protein. This protein and the mechanism thereof may provide insight regarding a new therapeutic target for treatment of human granulocytic anaplasmosis.
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Affiliation(s)
- Hua Niu
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, United States of America
| | - Vera Kozjak-Pavlovic
- Biocenter, Department of Microbiology, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Thomas Rudel
- Biocenter, Department of Microbiology, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Yasuko Rikihisa
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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52
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Expressing and functional analysis of mammalian apoptotic regulators in yeast. Cell Death Differ 2009; 17:737-45. [DOI: 10.1038/cdd.2009.177] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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53
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Bax Inhibitor-1, a conserved cell death suppressor, is a key molecular switch downstream from a variety of biotic and abiotic stress signals in plants. Int J Mol Sci 2009; 10:3149-3167. [PMID: 19742129 PMCID: PMC2738916 DOI: 10.3390/ijms10073149] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 07/06/2009] [Accepted: 07/06/2009] [Indexed: 02/03/2023] Open
Abstract
In Nature plants are constantly challenged by a variety of environmental stresses that could lead to disruptions in cellular homeostasis. Programmed cell death (PCD) is a fundamental cellular process that is often associated with defense responses to pathogens, during development and in response to abiotic stresses in fungi, animals and plants. Although there are many characteristics shared between different types of PCD events, it remains unknown whether a common mechanism drives various types of PCD in eukaryotes. One candidate regulator for such a mechanism is Bax Inhibitor-1 (BI-1), an evolutionary conserved, endoplasmic reticulum (ER)-resident protein that represents an ancient cell death regulator that potentially regulates PCD in all eukaryotes. Recent findings strongly suggested that BI-1 plays an important role in the conserved ER stress response pathway to modulate cell death induction in response to multiple types of cell death signals. As ER stress signaling pathways has been suggested to play important roles not only in the control of ER homeostasis but also in other biological processes such as the response to pathogens and abiotic stress in plants, BI-1 might function to control the convergence point that modulates the level of the “pro-survival and pro-death” signals under multiple stress conditions.
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54
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Mazzoni C, Torella M, Petrera A, Palermo V, Falcone C. PGK1, the gene encoding the glycolitic enzyme phosphoglycerate kinase, acts as a multicopy suppressor of apoptotic phenotypes in S. cerevisiae. Yeast 2009; 26:31-7. [PMID: 19180641 DOI: 10.1002/yea.1647] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In a previous paper we reported the construction of a S. cerevisiae strain lacking the essential gene LSM4, which could survive by the introduction of a truncated form of the orthologous gene from Kluyveromyces lactis. This strain showed apoptotic hallmarks and other phenotypes, including an increased sensitivity to caffeine and acetic acid. The suppression of the latter phenotype by overexpressing yeast genes allowed the isolation of PGK1, the gene encoding the glycolytic enzyme phosphoglycerate kinase. This gene restored normal ageing, oxygen peroxide resistance and nuclear integrity in the mutant. Other phenotypes, such as caffeine sensitivity and glycerol utilization, were also suppressed.
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Affiliation(s)
- Cristina Mazzoni
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Cell and Developmental Biology, University of Rome La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy.
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55
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A newly identified essential complex, Dre2-Tah18, controls mitochondria integrity and cell death after oxidative stress in yeast. PLoS One 2009; 4:e4376. [PMID: 19194512 PMCID: PMC2633045 DOI: 10.1371/journal.pone.0004376] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 12/25/2008] [Indexed: 12/21/2022] Open
Abstract
A mutated allele of the essential gene TAH18 was previously identified in our laboratory in a genetic screen for new proteins interacting with the DNA polymerase delta in yeast [1]. The present work shows that Tah18 plays a role in response to oxidative stress. After exposure to lethal doses of H2O2, GFP-Tah18 relocalizes to the mitochondria and controls mitochondria integrity and cell death. Dre2, an essential Fe/S cluster protein and homologue of human anti-apoptotic Ciapin1, was identified as a molecular partner of Tah18 in the absence of stress. Moreover, Ciapin1 is able to replace yeast Dre2 in vivo and physically interacts with Tah18. Our results are in favour of an oxidative stress-induced cell death in yeast that involves mitochondria and is controlled by the newly identified Dre2-Tah18 complex.
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56
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Hadj Amor IY, Smaoui K, Chaabène I, Mabrouk I, Djemal L, Elleuch H, Allouche M, Mokdad-Gargouri R, Gargouri A. Human p53 induces cell death and downregulates thioredoxin expression in Saccharomyces cerevisiae. FEMS Yeast Res 2009; 8:1254-62. [PMID: 19054132 DOI: 10.1111/j.1567-1364.2008.00445.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The p53 tumour suppressor protein has a crucial role in controlling cell cycle and apoptosis in human cells and its inactivation by selective point mutations is associated with human cancers. Here we show that overexpression of the human wild-type (wt) p53 in Saccharomyces cerevisiae completely inhibits yeast growth under minimal media conditions. In contrast, the R248W 'hot spot' p53 mutant (one of the most frequent p53 mutations encountered in human cancers) does not impair yeast growth. Moreover, we report, for the first time, that the human wt p53 induces yeast cell death with characteristic markers of apoptosis: exposure of phosphatidylserine and DNA strand cleavage as shown by Annexin V staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay, respectively. In addition, p53 also has an impact on the expression of yeast genes. Using differential display and Northern blot analysis, we demonstrated that human wt p53 expression in yeast leads to gene repression of thioredoxin (TRX1/2), a highly conserved multifunctional antioxidative and antiapoptotic protein family. Accordingly, we demonstrated that reactive oxygen species (ROS) are highly produced in p53 yeast induced cell death as shown by dihydrorhodamine 123 staining. These results suggest that the generation of ROS is a key event in p53 yeast induced cell death.
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Affiliation(s)
- Ines Yacoubi Hadj Amor
- Laboratoire de Génétique Moléculaire des Eucaryotes, Centre de Biotechnologie de Sfax, Sfax, Tunisia
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57
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Cheng WY, Wu SL, Hsiang CY, Li CC, Lai TY, Lo HY, Shen WS, Lee CH, Chen JC, Wu HC, Ho TY. Relationship Between San-Huang-Xie-Xin-Tang and its herbal components on the gene expression profiles in HepG2 cells. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2008; 36:783-97. [PMID: 18711774 DOI: 10.1142/s0192415x08006235] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Traditional Chinese medicine (TCM) has been used for thousands of years. Most Chinese herbal formulae consist of several herbal components and have been used to treat various diseases. However, the mechanisms of most formulae and the relationship between formulae and their components remain to be elucidated. Here we analyzed the putative mechanism of San-Huang-Xie-Xin-Tang (SHXXT) and defined the relationship between SHXXT and its herbal components by microarray technique. HepG2 cells were treated with SHXXT or its components and the gene expression profiles were analyzed by DNA microarray. Gene set enrichment analysis indicated that SHXXT and its components displayed a unique anti-proliferation pattern via p53 signaling, p53 activated, and DNA damage signaling pathways in HepG2 cells. Network analysis showed that most genes were regulated by one molecule, p53. In addition, hierarchical clustering analysis showed that Rhizoma Coptis shared a similar gene expression profile with SHXXT. These findings may explain why Rhizoma Coptis is the principle herb that exerts the major effect in the herbal formula, SHXXT. Moreover, this is the first report to reveal the relationship between formulae and their herbal components in TCM by microarray and bioinformatics tools.
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Affiliation(s)
- Wen-Yu Cheng
- Molecular Biology Laboratory, Graduate Institute of Chinese Medical Science, Taichung 40402, Taiwan
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58
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Guérin R, Arseneault G, Dumont S, Rokeach LA. Calnexin is involved in apoptosis induced by endoplasmic reticulum stress in the fission yeast. Mol Biol Cell 2008; 19:4404-20. [PMID: 18701708 DOI: 10.1091/mbc.e08-02-0188] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Stress conditions affecting the functions of the endoplasmic reticulum (ER) cause the accumulation of unfolded proteins. ER stress is counteracted by the unfolded-protein response (UPR). However, under prolonged stress the UPR initiates a proapoptotic response. Mounting evidence indicate that the ER chaperone calnexin is involved in apoptosis caused by ER stress. Here, we report that overexpression of calnexin in Schizosaccharomyces pombe induces cell death with apoptosis markers. Cell death was partially dependent on the Ire1p ER-stress transducer. Apoptotic death caused by calnexin overexpression required its transmembrane domain (TM), and involved sequences on either side of the ER membrane. Apoptotic death caused by tunicamycin was dramatically reduced in a strain expressing endogenous levels of calnexin lacking its TM and cytosolic tail. This demonstrates the involvement of calnexin in apoptosis triggered by ER stress. A genetic screen identified the S. pombe homologue of the human antiapoptotic protein HMGB1 as a suppressor of apoptotic death due to calnexin overexpression. Remarkably, overexpression of human calnexin in S. pombe also provoked apoptotic death. Our results argue for the conservation of the role of calnexin in apoptosis triggered by ER stress, and validate S. pombe as a model to elucidate the mechanisms of calnexin-mediated cell death.
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Affiliation(s)
- Renée Guérin
- Department of Biochemistry, Université de Montréal, Montréal, QC H3C 3J7, Canada
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59
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Huard S, Chen M, Burdette KE, Fenyvuesvolgyi C, Yu M, Elder RT, Zhao RY. HIV-1 Vpr-induced cell death in Schizosaccharomyces pombe is reminiscent of apoptosis. Cell Res 2008; 18:961-73. [DOI: 10.1038/cr.2008.272] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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60
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Cadmium induces a heterogeneous and caspase-dependent apoptotic response in Saccharomyces cerevisiae. Apoptosis 2008; 13:811-21. [PMID: 18463984 DOI: 10.1007/s10495-008-0215-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The toxic metal cadmium is linked to a series of degenerative disorders in humans, in which Cd-induced programmed cell death (apoptosis) may play a role. The yeast, Saccharomyces cerevisiae, provides a valuable model for elucidating apoptosis mechanisms, and this study extends that capability to Cd-induced apoptosis. We demonstrate that S. cerevisiae undergoes a glucose-dependent, programmed cell death in response to low cadmium concentrations, which is initiated within the first hour of Cd exposure. The response was associated with induction of the yeast caspase, Yca1p, and was abolished in a yca1Delta mutant. Cadmium-dependent apoptosis was also suppressed in a gsh1Delta mutant, indicating a requirement for glutathione. Other apoptotic markers, including sub-G(1) DNA fragmentation and hyper-polarization of mitochondrial membranes, were also evident among Cd-exposed cells. These responses were not distributed uniformly throughout the cell population, but were restricted to a subset of cells. This apoptotic subpopulation also exhibited markedly elevated levels of intracellular reactive oxygen species (ROS). The heightened ROS levels alone were not sufficient to induce apoptosis. These findings highlight several new perspectives to the mechanism of Cd-dependent apoptosis and its phenotypic heterogeneity, while opening up future analyses to the power of the yeast model system.
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61
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Pereira C, Silva R, Saraiva L, Johansson B, Sousa M, Côrte-Real M. Mitochondria-dependent apoptosis in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1286-302. [DOI: 10.1016/j.bbamcr.2008.03.010] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 03/05/2008] [Accepted: 03/13/2008] [Indexed: 12/18/2022]
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62
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Ramsdale M. Programmed cell death in pathogenic fungi. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1369-80. [DOI: 10.1016/j.bbamcr.2008.01.021] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 01/22/2008] [Accepted: 01/24/2008] [Indexed: 01/27/2023]
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63
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The pleiotropic effects of heterologous Bax expression in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1449-65. [DOI: 10.1016/j.bbamcr.2007.12.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 12/14/2007] [Accepted: 12/30/2007] [Indexed: 12/27/2022]
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64
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Braun RJ, Zischka H. Mechanisms of Cdc48/VCP-mediated cell death — from yeast apoptosis to human disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1418-35. [DOI: 10.1016/j.bbamcr.2008.01.015] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 01/16/2008] [Indexed: 10/22/2022]
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65
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Ring G, Khoury CM, Solar AJ, Yang Z, Mandato CA, Greenwood MT. Transmembrane protein 85 from both human (TMEM85) and yeast (YGL231c) inhibit hydrogen peroxide mediated cell death in yeast. FEBS Lett 2008; 582:2637-42. [DOI: 10.1016/j.febslet.2008.06.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 06/06/2008] [Accepted: 06/20/2008] [Indexed: 10/21/2022]
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66
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Hauptmann P, Lehle L. Kex1 protease is involved in yeast cell death induced by defective N-glycosylation, acetic acid, and chronological aging. J Biol Chem 2008; 283:19151-63. [PMID: 18474590 DOI: 10.1074/jbc.m801303200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
N-glycosylation in the endoplasmic reticulum is an essential protein modification and highly conserved in evolution from yeast to humans. The key step of this pathway is the transfer of the lipid-linked core oligosaccharide to the nascent polypeptide chain, catalyzed by the oligosaccharyltransferase complex. Temperature-sensitive oligosaccharyltransferase mutants of Saccharomyces cerevisiae at the restrictive temperature, such as wbp1-1, as well as wild-type cells in the presence of the N-glycosylation inhibitor tunicamycin display typical apoptotic phenotypes like nuclear condensation, DNA fragmentation, phosphatidylserine translocation, caspase-like activity, and reactive oxygen species accumulation. Since deletion of the yeast metacaspase YCA1 did not abrogate this death pathway, we postulated a different proteolytic process to be responsible. Here, we show that Kex1 protease is involved in the programmed cell death caused by defective N-glycosylation. Its disruption decreases caspase-like activity, production of reactive oxygen species, and fragmentation of mitochondria and, conversely, improves growth and survival of cells. Moreover, we demonstrate that Kex1 contributes also to the active cell death program induced by acetic acid stress or during chronological aging, suggesting that Kex1 plays a more general role in cellular suicide of yeast.
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Affiliation(s)
- Peter Hauptmann
- Lehrstuhl für Zellbiologie und Pflanzenphysiologie, Universität Regensburg, Universitätstrasse 31, 93053 Regensburg, Germany
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67
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Mroczek S, Kufel J. Apoptotic signals induce specific degradation of ribosomal RNA in yeast. Nucleic Acids Res 2008; 36:2874-88. [PMID: 18385160 PMCID: PMC2396418 DOI: 10.1093/nar/gkm1100] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 11/26/2007] [Accepted: 11/26/2007] [Indexed: 11/13/2022] Open
Abstract
Organisms exposed to reactive oxygen species, generated endogenously during respiration or by environmental conditions, undergo oxidative stress. Stress response can either repair the damage or activate one of the programmed cell death (PCD) mechanisms, for example apoptosis, and finally end in cell death. One striking characteristic, which accompanies apoptosis in both vertebrates and yeast, is a fragmentation of cellular DNA and mammalian apoptosis is often associated with degradation of different RNAs. We show that in yeast exposed to stimuli known to induce apoptosis, such as hydrogen peroxide, acetic acid, hyperosmotic stress and ageing, two large subunit ribosomal RNAs, 25S and 5.8S, became extensively degraded with accumulation of specific intermediates that differ slightly depending on cell death conditions. This process is most likely endonucleolytic, is correlated with stress response, and depends on the mitochondrial respiratory status: rRNA is less susceptible to degradation in respiring cells with functional defence against oxidative stress. In addition, RNA fragmentation is independent of two yeast apoptotic factors, metacaspase Yca1 and apoptosis-inducing factor Aif1, but it relies on the apoptotic chromatin condensation induced by histone H2B modifications. These data describe a novel phenotype for certain stress- and ageing-related PCD pathways in yeast.
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Affiliation(s)
| | - Joanna Kufel
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
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68
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Hamann A, Brust D, Osiewacz HD. Apoptosis pathways in fungal growth, development and ageing. Trends Microbiol 2008; 16:276-83. [PMID: 18440231 DOI: 10.1016/j.tim.2008.03.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Revised: 02/22/2008] [Accepted: 03/26/2008] [Indexed: 10/22/2022]
Abstract
Apoptosis is one type of programmed cell death with great importance for development and homeostasis of multicellular organisms. Unexpectedly, during the past decade, evidence has been obtained for the existence of a basal apoptosis machinery in yeast, as unicellular fungus, and in some filamentous fungi, a group of microorganisms that are neither true unicellular nor true multicellular biological systems but something in between. Here, we review evidence for a role of apoptotic processes in fungal pathogenicity, competitiveness, propagation, ageing and lifespan control.
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Affiliation(s)
- Andrea Hamann
- Institute for Molecular Biosciences, Department of Biosciences and Cluster of Excellence Macromolecular Complexes, J.W. Goethe-University, Max-von-Laue-Strasse 9, Frankfurt, Germany
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69
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Fabrizio P, Longo VD. Chronological aging-induced apoptosis in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1280-5. [PMID: 18445486 DOI: 10.1016/j.bbamcr.2008.03.017] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 03/18/2008] [Accepted: 03/27/2008] [Indexed: 12/15/2022]
Abstract
Saccharomyces cerevisiae is the simplest among the major eukaryotic model organisms for aging and diseases. Longevity in the chronological life span paradigm is measured as the mean and maximum survival period of populations of non-dividing yeast. This paradigm has been used successfully to identify several life-regulatory genes and three evolutionary conserved pro-aging pathways. More recently, Schizosaccharomyces pombe has been shown to age chronologically in a manner that resembles that of S. cerevisiae and that depends on the activity of the homologues of two pro-aging proteins previously identified in the budding yeast. Both yeast show features of apoptotic death during chronological aging. Here, we review some fundamental aspects of the genetics of chronological aging and the overlap between yeast aging and apoptotic processes with particular emphasis on the identification of an aging/death program that favors the dedifferentiation and regrowth of a few better adapted mutants generated within populations of aging S. cerevisiae. We also describe the use of a genome-wide screening technique to gain further insights into the mechanisms of programmed death in populations of chronologically aging S. cerevisiae.
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Affiliation(s)
- Paola Fabrizio
- Andrus Gerontology Center, Division of Biogerontology, University of Southern California, Los Angeles, CA 90089-0191, USA.
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70
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Owsianowski E, Walter D, Fahrenkrog B. Negative regulation of apoptosis in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1303-10. [PMID: 18406356 DOI: 10.1016/j.bbamcr.2008.03.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 03/08/2008] [Accepted: 03/12/2008] [Indexed: 12/29/2022]
Abstract
In recent years, yeast has been proven to be a useful model organism for studying programmed cell death. It not only exhibits characteristic markers of apoptotic cell death when heterologous inducers of apoptosis are expressed or when treated with apoptosis inducing drugs such as hydrogen peroxide (H(2)O(2)) or acetic acid, but contains homologues of several components of the apoptotic machinery identified in mammals, flies and nematodes, such as caspases, apoptosis inducing factor (AIF), Omi/HtrA2 and inhibitor-of-apoptosis proteins (IAPs). In this review, we focus on the role of negative regulators of apoptosis in yeasts. Bir1p is the only IAP protein in Saccharomyces cerevisiae and has long been known to play a role in cell cycle progression by acting as kinetochore and chromosomal passenger protein. Recent data established Bir1p's protective function against programmed cell death induced by H(2)O(2) treatment and in chronological ageing. Other factors that have a direct or indirect influence on intracellular levels of reactive oxygen species (ROS) and thus lead to apoptosis if they are misregulated or non-functional will be discussed.
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Affiliation(s)
- Esther Owsianowski
- ME Müller Institute for Structural Biology, Biozentrum, University of Basel, Basel, Switzerland
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71
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Iraqui I, Faye G, Ragu S, Masurel-Heneman A, Kolodner RD, Huang ME. Human peroxiredoxin PrxI is an orthologue of yeast Tsa1, capable of suppressing genome instability in Saccharomyces cerevisiae. Cancer Res 2008; 68:1055-63. [PMID: 18281480 DOI: 10.1158/0008-5472.can-07-2683] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The peroxiredoxins (Prx) are conserved antioxidant proteins that use cysteine as the primary site of oxidation during the reduction of peroxides. Many organisms have more than one isoform of Prx. Deletion of TSA1, one of five Prxs in yeast Saccharomyces cerevisiae, results in accumulation of a broad spectrum of mutations including gross chromosomal rearrangements. Deletion of TSA1 is synthetically lethal with mutations in RAD6 and several key genes involved in DNA double-strand break repair. Here, we have examined the function of human PrxI and PrxII, which share a high degree of sequence identity with Tsa1, by expressing them in S. cerevisiae cells under the control of the native TSA1 promoter. We found that expression of PrxI, but not PrxII, was capable of complementing a tsa1Delta mutant for a variety of defects including genome instability, the synthetic lethality observed in rad6 Delta tsa1Delta and rad51 Delta tsa1Delta double mutants, and mutagen sensitivity. Moreover, expression of either Tsa1 or PrxI prevented Bax-induced cell death. These data indicate that PrxI is an orthologue of Tsa1. PrxI and Tsa1 seem to act on the same substrates in vivo and share similar mechanisms of function. The observation that PrxI is involved in suppressing genome instability and protecting against cell death potentially provides a better understanding of the consequences of PrxI dysfunction in human cells. The S. cerevisiae system described here could provide a sensitive tool to uncover the mechanisms that underlie the function of human Prxs.
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Affiliation(s)
- Ismail Iraqui
- UMR2027 Centre National de la Recherche Scientifique, Institut Curie, Centre Universitaire, Orsay, France
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72
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Liang Q, Li W, Zhou B. Caspase-independent apoptosis in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1311-9. [PMID: 18358844 DOI: 10.1016/j.bbamcr.2008.02.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 01/31/2008] [Accepted: 02/20/2008] [Indexed: 12/31/2022]
Abstract
Apoptosis is a highly regulated cellular suicide program crucial for metazoan development. Yeast counterparts of central metazoan apoptotic regulators, such as metacaspase Yca1p, have been identified. In spite of the importance of Yca1p in yeast apoptotic process, many other factors such as Aif1p, orthologs of EndoG, AMID and cyclophilin D play important roles in caspase-independent apoptotic pathways. This review summarized recent progress about studies of various intrinsic and extrinsic apoptotic stimuli that may induce yeast cell death via caspase-independent apoptosis.
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Affiliation(s)
- Qiuli Liang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China
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73
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Mazzoni C, Falcone C. Caspase-dependent apoptosis in yeast. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1320-7. [PMID: 18355456 DOI: 10.1016/j.bbamcr.2008.02.015] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 02/12/2008] [Accepted: 02/13/2008] [Indexed: 01/02/2023]
Abstract
Damaging environment, certain intracellular defects or heterologous expression of pro-apoptotic genes induce death in yeast cells exhibiting typical markers of apoptosis. In mammals, apoptosis can be directed by the activation of groups of proteases, called caspases, that cleave specific substrates and trigger cell death. In addition, in plants, fungi, Dictyostelium and metazoa, paracaspases and metacaspases have been identified that share some homologies with caspases but showing different substrate specificity. In the yeast Saccharomyces cerevisiae, a gene (MCA1/YCA1) has been identified coding for a metacaspase involved in the induction of cell death. Metacaspases are not biochemical, but sequence and functional homologes of caspases, as deletion of them rescues entirely different death scenarios. In this review we will summarize the current knowledge in S. cerevisiae on apoptotic processes, induced by internal and external triggers, which are dependent on the metacaspase gene YCA1.
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Affiliation(s)
- Cristina Mazzoni
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Cell and Developmental Biology, University of Rome La Sapienza Piazzale Aldo Moro 5, Rome, Italy.
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74
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Aouida M, Mekid H, Belhadj O, Mir LM, Tounekti O. Mitochondria-independent morphological and biochemical apoptotic alterations promoted by the anti-tumor agent bleomycin in Saccharomyces cerevisiae. Biochem Cell Biol 2007; 85:49-55. [PMID: 17464344 DOI: 10.1139/o06-147] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bleomycin is a highly potent cytotoxic and genotoxic agent used in the chemotherapy of various types of tumors. It is a radiomimetic anticancer drug that produces single- and double-stranded DNA breaks in a catalytic way. Using Saccharomyces cerevisiae as a model system, we show that when a high amount of bleomycin molecules is internalized (100 micromol/L), morphological changes identical to those usually associated with apoptosis, i.e., a sub-G1 region peak, chromatin condensation, and very rapid DNA fragmentation into oligonucleosomal-sized fragments, are observed. The known bleomycin inhibitors cobalt and EDTA were able to prevent bleomycin nucleasic activity and thus apoptotic cell death. However, both oligomycin, a potent inhibitor of the mitochondrial F0F1-ATPase, and antimycin, a drug affecting mitochondria respiration, were unable to prevent the bleomycin-induced apoptotic-like cell death. These results suggest that high bleomycin concentrations induce an apoptosis-like mitochondria-independent cell death in yeast.
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Affiliation(s)
- Mustapha Aouida
- Laboratoire de Vectorologie et Transfert de Gènes, UMR 8121 CNRS, Institut Gustave-Roussy, 39 rue Camille Desmoulins, 94805 Villejuif Cédex, France.
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75
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Oshima R, Yoshinaga K, Ihara-Ohori Y, Fukuda R, Ohta A, Uchimiya H, Kawai-Yamada M. The Bax lnhibitor-1 needs a functional electron transport chain for cell death suppression. FEBS Lett 2007; 581:4627-32. [PMID: 17825821 DOI: 10.1016/j.febslet.2007.08.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Revised: 08/13/2007] [Accepted: 08/27/2007] [Indexed: 12/27/2022]
Abstract
Bax inhibitor-1 (BI-1) is an evolutionarily conserved cell death suppresser in animals, yeast, and plants. In this study, yeast strains carrying single-gene deletions were screened for factors related to cell death suppression by Arabidopsis BI-1 (AtBI-1). Our screen identified mutants that failed to survive Bax-induced lethality even with AtBI-1 coexpression (Bax suppressor). The Deltacox16 strain was isolated as a BI-1-inactive mutant; it was disrupted in a component of the mitochondrial cytochrome c oxidase. Other mutants defective in mitochondrial electron transport showed a similar phenotype. ATP levels were markedly decreased in all these mutants, suggesting that BI-1 requires normal electron transport activity to suppress cell death in yeast.
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Affiliation(s)
- Reiko Oshima
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
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76
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Lee YJ, Hoe KL, Maeng PJ. Yeast cells lacking the CIT1-encoded mitochondrial citrate synthase are hypersusceptible to heat- or aging-induced apoptosis. Mol Biol Cell 2007; 18:3556-67. [PMID: 17615299 PMCID: PMC1951759 DOI: 10.1091/mbc.e07-02-0118] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
In Saccharomyces cerevisiae, the initial reaction of the tricarboxylic acid cycle is catalyzed by the mitochondrial citrate synthase Cit1. The function of Cit1 has previously been studied mainly in terms of acetate utilization and metabolon construction. Here, we report the relationship between the function of Cit1 and apoptosis. Yeast cells with cit1 deletion showed a temperature-sensitive growth phenotype, and they displayed a rapid loss in viability associated with typical apoptotic hallmarks, i.e., reactive oxygen species (ROS) accumulation and nuclear fragmentation, DNA breakage, and phosphatidylserine translocation, when exposed to heat stress. On long-term cultivation, cit1 null strains showed increased potentials for both aging-induced apoptosis and adaptive regrowth. Activation of the metacaspase Yca1 was detected during heat- or aging-induced apoptosis in cit1 null strains, and accordingly, deletion of YCA1 suppressed the apoptotic phenotype caused by cit1 null mutation. Cells with cit1 deletion showed higher tendency toward glutathione (GSH) depletion and subsequent ROS accumulation than the wild type, which was rescued by exogenous GSH, glutamate, or glutathione disulfide (GSSG). These results led us to conclude that GSH deficiency in cit1 null cells is caused by an insufficient supply of glutamate necessary for biosynthesis of GSH rather than the depletion of reducing power required for reduction of GSSG to GSH.
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Affiliation(s)
- Yong Joo Lee
- *Department of Microbiology, School of Bioscience and Biotechnology, Chungnam National University, 305-764 Daejeon, Korea; and
| | - Kwang Lae Hoe
- Functional Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, 305-806 Daejeon, Korea
| | - Pil Jae Maeng
- *Department of Microbiology, School of Bioscience and Biotechnology, Chungnam National University, 305-764 Daejeon, Korea; and
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77
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Abstract
In the last decade, research into the molecular determinants of aging has progressed rapidly and much of this progress can be attributed to studies in invertebrate eukaryotic model organisms. Of these, single-celled yeast is the least complicated and most amenable to genetic and molecular manipulations. Supporting the use of this organism for aging research, increasing evidence has accumulated that a subset of pathways influencing longevity in yeast are conserved in other eukaryotes, including mammals. Here we briefly outline aging in yeast and describe recent findings that continue to keep this "simple" eukaryote at the forefront of aging research.
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Affiliation(s)
- Matt Kaeberlein
- * To whom correspondence should be addressed. E-mails: (MK); (BKK)
| | | | - Brian K Kennedy
- * To whom correspondence should be addressed. E-mails: (MK); (BKK)
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78
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Majors BS, Betenbaugh MJ, Chiang GG. Links between metabolism and apoptosis in mammalian cells: applications for anti-apoptosis engineering. Metab Eng 2007; 9:317-26. [PMID: 17611135 DOI: 10.1016/j.ymben.2007.05.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Revised: 05/16/2007] [Accepted: 05/16/2007] [Indexed: 10/23/2022]
Abstract
Production of complex recombinant proteins requires the culture of mammalian cells in bioreactors. Inherent in these cultures is the problem of cell death, which can result from nutrient depletion, byproduct accumulation, and other bioreactor stresses which signal the cell to die through apoptosis, or programmed cell death. Apoptosis is a highly regulated pathway of both pro- and anti-apoptotic proteins that promote cell survival or death, and cell engineering efforts to inhibit the apoptosis pathway have led to increased culture viability and recombinant protein production. Originally, the exclusive function of many of these pathway proteins was believed to be binding at the mitochondria and regulating apoptosis through modulation of the mitochondria permeability. While this protein functionality does still hold true, it is now evident that these proteins also include roles in the metabolic processes of the mitochondria. Furthermore, apoptosis pathway proteins in other organelles within the cell may also both modulate apoptosis and metabolism. This review first details the known links that exist between apoptosis proteins and metabolic functions in the cytosol, mitochondria, and endoplasmic reticulum. Second, the review turns to look at potentially new cell engineering strategies that are linked to metabolism for improving cell culture viability and protein production.
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Affiliation(s)
- Brian S Majors
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, 3400 North Charles Street, 221 Maryland Hall, Baltimore, MD 21218-2694, USA
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79
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Fröhlich KU, Fussi H, Ruckenstuhl C. Yeast apoptosis—From genes to pathways. Semin Cancer Biol 2007; 17:112-21. [PMID: 17207637 DOI: 10.1016/j.semcancer.2006.11.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Accepted: 11/25/2006] [Indexed: 11/23/2022]
Abstract
Yeast are eukaryotic unicellular organisms that are easy to cultivate and offer a wide spectrum of genetic and cytological tools for research. Yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe have successfully been used as models for human cell division cycle. Stress conditions, cellular ageing, failed mating, certain mutations or heterologous expression of proapoptotic genes induce yeast cell death with the characteristic markers of apoptosis. Several crucial regulators of apoptosis are conserved between metazoans and yeast. This simple model organism offers the possibility to identify conserved and new components of the apoptotic machinery and to elucidate the regulatory pathways beyond.
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80
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Sanjuán Szklarz LK, Kozjak-Pavlovic V, Vögtle FN, Chacinska A, Milenkovic D, Vogel S, Dürr M, Westermann B, Guiard B, Martinou JC, Borner C, Pfanner N, Meisinger C. Preprotein Transport Machineries of Yeast Mitochondrial Outer Membrane Are not Required for Bax-induced Release of Intermembrane Space Proteins. J Mol Biol 2007; 368:44-54. [PMID: 17335847 DOI: 10.1016/j.jmb.2007.01.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 12/22/2006] [Accepted: 01/04/2007] [Indexed: 10/23/2022]
Abstract
The mitochondrial outer membrane contains protein import machineries, the translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). It has been speculated that TOM or SAM are required for Bax-induced release of intermembrane space (IMS) proteins; however, experimental evidence has been scarce. We used isolated yeast mitochondria as a model system and report that Bax promoted an efficient release of soluble IMS proteins while preproteins were still imported, excluding an unspecific damage of mitochondria. Removal of import receptors by protease treatment did not inhibit the release of IMS proteins by Bax. Yeast mutants of each Tom receptor and the Tom40 channel were not impaired in Bax-induced protein release. We analyzed a large collection of mutants of mitochondrial outer membrane proteins, including SAM, fusion and fission components, but none of these components was required for Bax-induced protein release. The released proteins included complexes up to a size of 230 kDa. We conclude that Bax promotes efficient release of IMS proteins through the outer membrane of yeast mitochondria while the inner membrane remains intact. Inactivation of the known protein import and sorting machineries of the outer membrane does not impair the function of Bax at the mitochondria.
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Affiliation(s)
- Luiza K Sanjuán Szklarz
- Institut für Biochemie und Molekularbiologie, Zentrum für Biochemie und Molekulare Zellforschung, Universität Freiburg, Hermann-Herder-Strasse 7, D-79104 Freiburg, Germany
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81
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Abstract
Mitochondria are not only important for the energetic status of the cell, but are also the fatal organelles deciding about cellular life and death. Complex mitochondrial features decisive for cell death execution in mammals are present and functional in yeast: AIF and cytochrome c release to the cytosol, mitochondrial fragmentation as well as mitochondrial hyperpolarisation followed by an oxidative burst, and breakdown of mitochondrial membrane potential. The easy accessibility of mitochondrial manipulations such as repression of respiration by growing yeast on glucose or deletion of mitochondrial DNA (rho(0)) on the one hand and the unique ability of yeast cells to grow on non-fermentable carbon sources by switching on mitochondrial respiration on the other hand have made yeast an excellent tool to delineate the necessity for mitochondria in cell death execution. Yeast research indicates that the connection between mitochondria and apoptosis is intricate, as abrogation of mitochondrial function can be either deleterious or beneficial for the cell depending on the specific context of the death scenario. Surprisingly, mitochondrion dependent yeast apoptosis currently helps to understand the aetiology (or the complex biology) of lethal cytoskeletal alterations, ageing and neurodegeneration. For example, mutation of mitochondrial superoxide dismutase or CDC48/VCP mutations, both implicated in several neurodegenerative disorders, are associated with mitochondrial impairment and apoptosis in yeast.
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Affiliation(s)
- Tobias Eisenberg
- Institute of Molecular Biosciences, Universitätsplatz 2, University of Graz, 8010 Graz, Austria
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82
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Barhoom S, Sharon A. Bcl-2 proteins link programmed cell death with growth and morphogenetic adaptations in the fungal plant pathogen Colletotrichum gloeosporioides. Fungal Genet Biol 2007; 44:32-43. [PMID: 16950636 DOI: 10.1016/j.fgb.2006.06.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2006] [Revised: 06/05/2006] [Accepted: 06/13/2006] [Indexed: 10/24/2022]
Abstract
Proteins belonging to the Bcl-2 family regulate apoptosis in mammals by controlling mitochondria efflux of cytochrome c and other apoptosis-related proteins. Homologues of human Bcl-2 proteins are found in different metazoan organisms where they play a similar role, while they seem to be absent in plants and fungi. Nonetheless, Bcl-2 protein members can induce or prevent yeast cell death, suggesting that enough functional conservation exists between apoptotic machineries of mammals and fungi. Here we show that induction or prevention of apoptosis by Bcl-2 proteins in the fungal plant pathogen Colletotrichum gloeosporioides is tightly linked with growth and morphogenetic adaptation that occur throughout the entire fungal life cycle. Isolates expressing the pro-apoptotic Bax protein underwent cell death with apoptotic characteristics, and showed alterations in conidial germination that are associated with pathogenic and non-pathogenic life styles. Isolates expressing the anti-apoptotic Bcl-2 protein had prolonged longevity, were protected from Bax-induced cell death, and exhibited enhanced stress resistance. These isolates also had enhanced mycelium and conidia production, and were hyper virulent to host plants. Our findings show that apoptotic-associated machinery regulates morphogenetic switches, which are critical for proper responses and adaptation fungi to different environments.
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Affiliation(s)
- Sima Barhoom
- Department of Plant Sciences, Tel Aviv University, Tel Aviv, Israel
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83
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Bounhar Y, Mann KK, Roucou X, LeBlanc AC. Prion protein prevents Bax-mediated cell death in the absence of other Bcl-2 family members inSaccharomyces cerevisiae. FEMS Yeast Res 2006; 6:1204-12. [PMID: 17156017 DOI: 10.1111/j.1567-1364.2006.00122.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Although there is no consensus regarding the normal function of the prion protein, increasing evidence points towards a role in cellular protection against cell death. We have previously shown that prion protein is a potent inhibitor of Bax-induced apoptosis in human primary neurons and in the breast carcinoma MCF-7 cells. Here, we used the yeast Saccharomyces cerevisiae to investigate if the neuroprotective function of prion protein requires other members of the Bcl-2 family given that S. cerevisiae lacks Bcl-2 genes but undergoes a mitochondrial-dependent apoptotic cell death upon exogenous expression of Bax protein. We show that Bax induces cell death and growth inhibition in S. cerevisiae. Prion protein prevents Bax-mediated cell death. Prion protein overcomes Bax-mediated growth arrest in S phase but cannot overcome population growth inhibition because the cells then accumulate in G(2)/M phase. We conclude that prion protein does not require other Bcl-2 family proteins to protect against Bax-mediated cell death.
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Affiliation(s)
- Younes Bounhar
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
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84
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Li XP, Baricevic M, Saidasan H, Tumer NE. Ribosome depurination is not sufficient for ricin-mediated cell death in Saccharomyces cerevisiae. Infect Immun 2006; 75:417-28. [PMID: 17101666 PMCID: PMC1828414 DOI: 10.1128/iai.01295-06] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The plant toxin ricin is one of the most potent and lethal substances known. Ricin inhibits protein synthesis by removing a specific adenine from the highly conserved alpha-sarcin/ricin loop in the large rRNA. Very little is known about how ricin interacts with ribosomes and the molecular mechanism by which it kills cells. To gain insight to the mechanism of ricin-induced cell death, we set up yeast (Saccharomyces cerevisiae) as a simple and genetically tractable system to isolate mutants defective in cytotoxicity. Ribosomes were depurinated in yeast cells expressing the precursor form of the A chain of ricin (pre-RTA), and these cells displayed apoptotic markers such as nuclear fragmentation, chromatin condensation, and accumulation of reactive oxygen species. We conducted a large-scale mutagenesis of pre-RTA and isolated a panel of nontoxic RTA mutants based on their inability to kill yeast cells. Several nontoxic RTA mutants depurinated ribosomes and inhibited translation to the same extent as wild-type RTA in vivo. The mutant proteins isolated from yeast depurinated ribosomes in vitro, indicating that they were catalytically active. However, cells expressing these mutants did not display hallmarks of apoptosis. These results provide the first evidence that the ability to depurinate ribosomes and inhibit translation does not always correlate with ricin-mediated cell death, indicating that ribosome depurination and translation inhibition do not account entirely for the cytotoxicity of ricin.
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Affiliation(s)
- Xiao-Ping Li
- Biotechnology Center, Foran Hall, Cook College, 59 Dudley Road, New Brunswick, NJ 08901-8520, USA
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85
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Eichmann R, Dechert C, Kogel KH, Hückelhoven R. Transient over-expression of barley BAX Inhibitor-1 weakens oxidative defence and MLA12-mediated resistance to Blumeria graminis f.sp. hordei. MOLECULAR PLANT PATHOLOGY 2006; 7:543-552. [PMID: 20507468 DOI: 10.1111/j.1364-3703.2006.00359.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
SUMMARY BAX Inhibitor-1 (BI-1) is a conserved cell death suppressor protein. In barley, BI-1 (HvBI-1) expression is induced upon powdery mildew infection and when over-expressed in epidermal cells of barley, HvBI-1 induces susceptibility to the biotrophic fungal pathogen Blumeria graminis. We co-expressed mammalian pro-apoptotic BAX together with HvBI-1, and the mammalian BAX antagonist BCL-X(L) in barley epidermal cells. BAX expression led to cessation of cytoplasmic streaming and collapse of the cytoplasm while co-expression of HvBI-1 and BCL-X(L) partially or completely, respectively, rescued cells from BAX lethality. When B. graminis was attacking epidermal cells, a green fluorescent protein fusion of HvBI-1 accumulated at the site of attempted penetration and was also present around haustoria. Over-expression of HvBI-1 in epidermal cells weakened a cell-wall-associated local hydrogen peroxide burst in a resistant mlo-mutant genotype and supported haustoria accommodation in race-specifically resistant MLA12-barley. HvBI-1 is a cell death regulator protein of barley with the potential to suppress host defence reactions.
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Affiliation(s)
- Ruth Eichmann
- Research Centre for BioSystems, Land Use and Nutrition, Institute of Phytopathology and Applied Zoology, Justus-Liebig-University Giessen, Heinrich-Buff Ring 26-32, D-35392 Giessen, Germany
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86
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Ribeiro GF, Côrte-Real M, Johansson B. Characterization of DNA damage in yeast apoptosis induced by hydrogen peroxide, acetic acid, and hyperosmotic shock. Mol Biol Cell 2006; 17:4584-91. [PMID: 16899507 PMCID: PMC1635349 DOI: 10.1091/mbc.e06-05-0475] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Saccharomyces cerevisiae has been reported to die, under certain conditions, from programmed cell death with apoptotic markers. One of the most important markers is chromosomal DNA fragmentation as indicated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining. We found TUNEL staining in S. cerevisiae to be a consequence of both single- and double-strand DNA breaks, whereas in situ ligation specifically stained double-strand DNA breaks. Cells treated with hydrogen peroxide or acetic acid staining positively for TUNEL assay stained negatively for in situ ligation, indicating that DNA damage in both cases mainly consists of single-strand DNA breaks. Pulsed field gel electrophoresis of chromosomal DNA from cells dying from hydrogen peroxide, acetic acid, or hyperosmotic shock revealed DNA breakdown into fragments of several hundred kilobases, consistent with the higher order chromatin degradation preceding DNA laddering in apoptotic mammalian cells. DNA fragmentation was associated with death by treatment with 10 mM hydrogen peroxide but not 150 mM and was absent if cells were fixed with formaldehyde to eliminate enzyme activity before hydrogen peroxide treatment. These observations are consistent with a process that, like mammalian apoptosis, is enzyme dependent, degrades chromosomal DNA, and is activated only at low intensity of death stimuli.
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Affiliation(s)
- Gabriela F. Ribeiro
- Departamento de Biologia, Centro de Biologia Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Manuela Côrte-Real
- Departamento de Biologia, Centro de Biologia Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Björn Johansson
- Departamento de Biologia, Centro de Biologia Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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87
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Hauptmann P, Riel C, Kunz-Schughart LA, Fröhlich KU, Madeo F, Lehle L. Defects in N-glycosylation induce apoptosis in yeast. Mol Microbiol 2006; 59:765-78. [PMID: 16420350 DOI: 10.1111/j.1365-2958.2005.04981.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
N-glycosylation in the endoplasmic reticulum is an essential protein modification and highly conserved in evolution from yeast to man. Defects of N-glycosylation in humans lead to congenital disorders. The pivotal step of this pathway is the transfer of the evolutionarily conserved lipid-linked core-oligosaccharide to the nascent polypeptide chain, catalysed by the oligosaccharyltransferase. One of its nine subunits, Ost2, has homology to DAD1, originally characterized in hamster cells as a defender against apoptotic death. Here we show that ost mutants, such as ost2 and wbp1-1, display morphological and biochemical features of apoptosis upon induction of the glycosylation defect. We observe nuclear condensation, DNA fragmentation as well as externalization of phosphatidylserine. We also demonstrate induction of caspase-like activity, both determined by flow cytometric analysis and in cell-free extracts. Similarly, the N-glycosylation inhibitor tunicamycin in combination with elevated temperature is able to challenge the apoptotic cascade. Heterologous expression of anti-apoptotic human Bcl-2 diminishes caspase activation, improves survival of cells and suppresses the temperature-sensitive growth defect of wbp1-1. Furthermore, accumulation of reactive oxygen species occurs in response to defective glycosylation. As deletion of the metacaspase YCA1 does not seem to abrogate glycosylation-induced apoptosis, we postulate a different proteolytic process to be involved in this death pathway.
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Affiliation(s)
- Peter Hauptmann
- Lehrstuhl für Zellbiologie und Pflanzenphysiologie, Universität Regensburg, Regensburg, Germany
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88
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Abstract
Ageing is widely believed to be a non-adaptive process that results from a decline in the force of natural selection. However, recent studies in Saccharomyces cerevisiae are consistent with the existence of a programme of altruistic ageing and death. We suggest that the similarities between the molecular pathways that regulate ageing in yeast, worms, flies and mice, together with evidence that is consistent with programmed death in salmon and other organisms, raise the possibility that programmed ageing or death can also occur in higher eukaryotes.
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Affiliation(s)
- Valter D Longo
- Andrus Gerontology Center and Department of Biological Sciences, University of Southern California, 3715 McClintock Avenue, Los Angeles, California 90089, USA.
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89
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Reekmans R, De Smet K, Chen C, Van Hummelen P, Contreras R. Old yellow enzyme interferes with Bax-induced NADPH loss and lipid peroxidation in yeast. FEMS Yeast Res 2005; 5:711-25. [PMID: 15851100 DOI: 10.1016/j.femsyr.2004.12.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2004] [Revised: 12/29/2004] [Accepted: 12/30/2004] [Indexed: 12/19/2022] Open
Abstract
The yeast transcriptional response to murine Bax expression was compared with the changes induced by H(2)O(2) treatment via microarray technology. Although most of the Bax-responsive genes were also triggered by H(2)O(2) treatment, OYE3, ICY2, MLS1 and BTN2 were validated to have a Bax-specific transcriptional response not shared with the oxidative stress trigger. In knockout experiments, only deletion of OYE3, coding for yeast Old yellow enzyme, attenuated the rate of Bax-induced growth arrest, cell death and NADPH decrease. Lipid peroxidation was completely absent in DeltaOYE3 expressing Bax. However, the absence of OYE3 sensitized yeast cells to H(2)O(2)-induced cell death, and increased the rate of NADPH decrease and lipid peroxidation. Our results clearly indicate that OYE3 interferes with Bax- and H(2)O(2)-induced lipid peroxidation and cell death in Saccharomyces cerevisiae.
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Affiliation(s)
- Rieka Reekmans
- Unit of Fundamental and Applied Molecular Biology, Department for Molecular Biomedical Research, VIB-Ghent University, Technologiepark 927, B-9052 Zwijnaarde, Belgium
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90
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Silva RD, Sotoca R, Johansson B, Ludovico P, Sansonetty F, Silva MT, Peinado JM, Côrte-Real M. Hyperosmotic stress induces metacaspase- and mitochondria-dependent apoptosis inSaccharomyces cerevisiae. Mol Microbiol 2005; 58:824-34. [PMID: 16238630 DOI: 10.1111/j.1365-2958.2005.04868.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During the last years, several reports described an apoptosis-like programmed cell death process in yeast in response to different environmental aggressions. Here, evidence is presented that hyperosmotic stress caused by high glucose or sorbitol concentrations in culture medium induces in Saccharomyces cerevisiae a cell death process accompanied by morphological and biochemical indicators of apoptotic programmed cell death, namely chromatin condensation along the nuclear envelope, mitochondrial swelling and reduction of cristae number, production of reactive oxygen species and DNA strand breaks, with maintenance of plasma membrane integrity. Disruption of AIF1 had no effect on cell survival, but lack of Yca1p drastically reduced metacaspase activation and decreased cell death indicating that this death process was associated to activation of this protease. Supporting the involvement of mitochondria and cytochrome c in caspase activation, the mutant strains cyc1Deltacyc7Delta and cyc3Delta, both lacking mature cytochrome c, displayed a decrease in caspase activation associated to increased cell survival when exposed to hyperosmotic stress. These findings indicate that hyperosmotic stress triggers S. cerevisiae into an apoptosis-like programmed cell death that is mediated by a caspase-dependent mitochondrial pathway partially dependent on cytochrome c.
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Affiliation(s)
- Rui D Silva
- Departamento de Biologia-Centro de Biologia Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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91
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Nevzglyadova OV, Artyomov AV, Mikhailova EV, Soidla TR. Bud selection and apoptosis-like degradation of nuclei in yeast heterokaryons: a KAR1 effect. Mol Genet Genomics 2005; 274:419-27. [PMID: 16160851 DOI: 10.1007/s00438-005-0036-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2005] [Accepted: 07/01/2005] [Indexed: 01/21/2023]
Abstract
It has been shown that defects in cell fusion during mating can trigger programmed cell death in the yeast Saccharomyces cerevisiae. We wished to test whether defects in nuclear migration during cell fusion have the same effect. A partial pedigree analysis of nine kar1 x KAR1 crosses of two different types (four alpha KAR1 x a kar1 and five alpha kar1 x a KAR1 crosses) was carried out, and quantitative estimates of the frequencies of different mother/daughter (m/d) classes were obtained. The kar1 mutation affects nuclear congression and delays nuclear fusion. In each cross tested, the nucleus that entered the first bud tended to be the one contributed by the cell that carried the wild-type allele of KAR1. If budding was delayed by nutrient limitation, the kar1 nucleus could be rescued, indicating that the primary effect of the kar1 mutation is that it slows spindle action. Many m/d classes appear as a result of the degradation of one of the nuclei in the heterokaryon. Loss of nuclei in heterokaryons was accompanied by an accumulation of reactive oxygen species (ROS), and by abnormalities in nuclear structure revealed by TUNEL (terminal transferase-mediated dUTP nick end-labeling) analysis, DAPI staining and by histone-GFP fluorescence patterns which suggested an apoptosis-like process. Often only one nucleus was degraded, and ROS accumulation was restricted to one half of the zygote. We therefore suggest that the data obtained can be explained by apoptosis-like death of a half-cell (cell body).
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Affiliation(s)
- Olga V Nevzglyadova
- Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Avenue 4, St., Petersburg, 194064, Russia.
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92
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Low CP, Liew LP, Pervaiz S, Yang H. Apoptosis and lipoapoptosis in the fission yeast Schizosaccharomyces pombe. FEMS Yeast Res 2005; 5:1199-206. [PMID: 16137929 DOI: 10.1016/j.femsyr.2005.07.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 07/05/2005] [Accepted: 07/20/2005] [Indexed: 11/29/2022] Open
Abstract
Yeasts being simple eukaryotes are established genetic systems that are often employed to solve important biological questions. Recently, it has become evident that certain cell death programs exist in these unicellular organisms. For example, it has been shown recently that strains of the fission yeast Schizosaccharomyces pombe deficient in triacylglycerol synthesis undergo cell death with prominent apoptotic markers. This minireview is intended to discuss key developments that have rendered fission yeast useful both as a tool and as a model for apoptosis and lipoapoptosis research. It is attempted to delineate a putative signaling pathway leading to the execution of lipoapoptosis in the fission yeast. Although in its infancy, apoptosis research in the fission yeast promises exciting breakthroughs in the near future.
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Affiliation(s)
- Choon Pei Low
- Department of Biochemistry, National University of Singapore, Republic of Singapore
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93
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Leiter É, Szappanos H, Oberparleiter C, Kaiserer L, Csernoch L, Pusztahelyi T, Emri T, Pócsi I, Salvenmoser W, Marx F. Antifungal protein PAF severely affects the integrity of the plasma membrane of Aspergillus nidulans and induces an apoptosis-like phenotype. Antimicrob Agents Chemother 2005; 49:2445-53. [PMID: 15917545 PMCID: PMC1140496 DOI: 10.1128/aac.49.6.2445-2453.2005] [Citation(s) in RCA: 127] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The small, basic, and cysteine-rich antifungal protein PAF is abundantly secreted into the supernatant by the beta-lactam producer Penicillium chrysogenum. PAF inhibits the growth of various important plant and zoopathogenic filamentous fungi. Previous studies revealed the active internalization of the antifungal protein and the induction of multifactorial detrimental effects, which finally resulted in morphological changes and growth inhibition in target fungi. In the present study, we offer detailed insights into the mechanism of action of PAF and give evidence for the induction of a programmed cell death-like phenotype. We proved the hyperpolarization of the plasma membrane in PAF-treated Aspergillus nidulans hyphae by using the aminonaphtylethenylpyridinium dye di-8-ANEPPS. The exposure of phosphatidylserine on the surface of A. nidulans protoplasts by Annexin V staining and the detection of DNA strand breaks by TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) gave evidence for a PAF-induced apoptotic-like mechanism in A. nidulans. The localization of reactive oxygen species (ROS) by dichlorodihydrofluorescein diacetate and the abnormal cellular ultrastructure analyzed by transmission electron microscopy suggested that ROS-elicited membrane damage and the disintegration of mitochondria played a major role in the cytotoxicity of PAF. Finally, the reduced PAF sensitivity of A. nidulans strain FGSC1053, which carries a dominant-interfering mutation in fadA, supported our assumption that G-protein signaling was involved in PAF-mediated toxicity.
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Affiliation(s)
- Éva Leiter
- Department of Microbiology and Biotechnology, Faculty of Science, Department of Physiology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary, Biocenter, Division of Molecular Biology, Innsbruck Medical University, Innsbruck, Austria, Institute of Zoology and Limnology, Division of Ultrastructure and Evolutionary Biology, University of Innsbruck, Innsbruck, Austria
| | - Henrietta Szappanos
- Department of Microbiology and Biotechnology, Faculty of Science, Department of Physiology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary, Biocenter, Division of Molecular Biology, Innsbruck Medical University, Innsbruck, Austria, Institute of Zoology and Limnology, Division of Ultrastructure and Evolutionary Biology, University of Innsbruck, Innsbruck, Austria
| | - Christoph Oberparleiter
- Department of Microbiology and Biotechnology, Faculty of Science, Department of Physiology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary, Biocenter, Division of Molecular Biology, Innsbruck Medical University, Innsbruck, Austria, Institute of Zoology and Limnology, Division of Ultrastructure and Evolutionary Biology, University of Innsbruck, Innsbruck, Austria
| | - Lydia Kaiserer
- Department of Microbiology and Biotechnology, Faculty of Science, Department of Physiology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary, Biocenter, Division of Molecular Biology, Innsbruck Medical University, Innsbruck, Austria, Institute of Zoology and Limnology, Division of Ultrastructure and Evolutionary Biology, University of Innsbruck, Innsbruck, Austria
| | - László Csernoch
- Department of Microbiology and Biotechnology, Faculty of Science, Department of Physiology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary, Biocenter, Division of Molecular Biology, Innsbruck Medical University, Innsbruck, Austria, Institute of Zoology and Limnology, Division of Ultrastructure and Evolutionary Biology, University of Innsbruck, Innsbruck, Austria
| | - Tünde Pusztahelyi
- Department of Microbiology and Biotechnology, Faculty of Science, Department of Physiology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary, Biocenter, Division of Molecular Biology, Innsbruck Medical University, Innsbruck, Austria, Institute of Zoology and Limnology, Division of Ultrastructure and Evolutionary Biology, University of Innsbruck, Innsbruck, Austria
| | - Tamás Emri
- Department of Microbiology and Biotechnology, Faculty of Science, Department of Physiology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary, Biocenter, Division of Molecular Biology, Innsbruck Medical University, Innsbruck, Austria, Institute of Zoology and Limnology, Division of Ultrastructure and Evolutionary Biology, University of Innsbruck, Innsbruck, Austria
| | - István Pócsi
- Department of Microbiology and Biotechnology, Faculty of Science, Department of Physiology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary, Biocenter, Division of Molecular Biology, Innsbruck Medical University, Innsbruck, Austria, Institute of Zoology and Limnology, Division of Ultrastructure and Evolutionary Biology, University of Innsbruck, Innsbruck, Austria
| | - Willibald Salvenmoser
- Department of Microbiology and Biotechnology, Faculty of Science, Department of Physiology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary, Biocenter, Division of Molecular Biology, Innsbruck Medical University, Innsbruck, Austria, Institute of Zoology and Limnology, Division of Ultrastructure and Evolutionary Biology, University of Innsbruck, Innsbruck, Austria
| | - Florentine Marx
- Department of Microbiology and Biotechnology, Faculty of Science, Department of Physiology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary, Biocenter, Division of Molecular Biology, Innsbruck Medical University, Innsbruck, Austria, Institute of Zoology and Limnology, Division of Ultrastructure and Evolutionary Biology, University of Innsbruck, Innsbruck, Austria
- Corresponding author. Mailing address: Biocenter, Division of Molecular Biology, Innsbruck Medical University, Fritz-Pregl Strasse 3, A-6020 Innsbruck, Austria. Phone: 43-512-5073607. Fax: 43-512-5079880. E-mail:
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94
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Polčic P, Su X, Fowlkes J, Blachly-Dyson E, Dowhan W, Forte M. Cardiolipin and phosphatidylglycerol are not required for the in vivo action of Bcl-2 family proteins. Cell Death Differ 2005; 12:310-2. [PMID: 15650753 PMCID: PMC4085678 DOI: 10.1038/sj.cdd.4401566] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- P Polčic
- Vollum Institute, Oregon Health & Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - X Su
- Department of Biochemistry & Molecular Biology, University of Texas-Houston, Medical School, 6431 Fannin, Suite 6.200, Houston, TX 77030, USA
| | - J Fowlkes
- Vollum Institute, Oregon Health & Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - E Blachly-Dyson
- Vollum Institute, Oregon Health & Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - W Dowhan
- Department of Biochemistry & Molecular Biology, University of Texas-Houston, Medical School, 6431 Fannin, Suite 6.200, Houston, TX 77030, USA
| | - M Forte
- Vollum Institute, Oregon Health & Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
- Corresponding author: M Forte, Vollum Institute, L474, Oregon Health & Sciences University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA. Tel.: +503-494-5454; Fax: +503-494-4976;
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95
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Sapienza K, Balzan R. Metabolic aspects of aspirin-induced apoptosis in yeast. FEMS Yeast Res 2005; 5:1207-13. [PMID: 15982932 DOI: 10.1016/j.femsyr.2005.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 04/19/2005] [Accepted: 05/03/2005] [Indexed: 10/25/2022] Open
Abstract
We have previously shown that aspirin induces apoptosis in manganese superoxide dismutase (MnSOD)-deficient Saccharomyces cerevisiae cells cultivated in ethanol medium, and that it exhibits a significant antioxidant effect until the onset of overt apoptosis. We here report that glucose-6-phosphate dehydrogenase activity in these cells is not inhibited by aspirin. However, the reducing power, as measured by the NADPH/NADP(+) concentration ratio, is significantly lower than in wild-type cells. With aspirin, the levels of NADPH, NADP(+) and catalase in MnSOD-deficient cells decrease significantly after 72 h of cultivation, without significant decrease of the NADPH/NADP(+) ratio. This ratio is higher when the cells are grown in glycerol or acetate medium. This seems to prevent loss in viability and induction of apoptosis on treatment with aspirin. Additionally, the glutathione (GSH) level is maintained, but the level of oxidized glutathione (GSSG) increases, leading to a significant decrease in the GSH/GSSG ratio in aspirin-treated cells. This decrease in the GSH/GSSG ratio is much less in cells grown in glycerol medium, while there is an increase in the GSH/GSSG ratio of cells grown in acetate medium. Consequently, the decreased reducing power may be linked to apoptotic induction by aspirin. This occurs independently of the level of reactive oxygen species which, as shown in our previous studies, do not play a primary role in the apoptosis of cells exposed to aspirin. The protective effect of MnSOD appears to be related to the cellular reducing power.
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Affiliation(s)
- Karen Sapienza
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida MSD 06, Malta
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96
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Gourlay CW, Ayscough KR. Identification of an upstream regulatory pathway controlling actin-mediated apoptosis in yeast. J Cell Sci 2005; 118:2119-32. [PMID: 15855235 DOI: 10.1242/jcs.02337] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The build up of reactive oxygen species (ROS) is known to contribute to a reduction in the lifespan of a cell and to their degeneration in diseases such as Alzheimer's and tissue ischaemia. It is therefore important to elucidate pathways that regulate cellular oxidative stress. We have previously shown that actin dynamics can affect the oxidative-stress burden on a yeast cell and thereby its potential lifespan. To elucidate further the connection between actin dynamics and oxidative stress, we sought to identify regulators of this process. The actin regulatory proteins Sla1p and End3p are important in maintaining a rapid turnover of F-actin in cortical patches. We show that cells expressing a mutated form of Sla1p or lacking End3p display markers of apoptosis such as depolarized mitochondrial membranes and elevated levels of reactive oxygen species. Overexpression of the ubiquitin ligase RSP5 can alleviate the oxidative-stress phenotype observed in cells lacking End3p by targeting Sla1p to the cortex and restoring actin remodelling capability. We also demonstrate that overexpression of PDE2, a negative regulator of the Ras/cAMP pathway rescues actin dynamics, reduces oxidative stress sensitivity and restores viability in deltaend3 cells. Our data suggest, for the first time, that a physiological link exists between actin regulation and cAMP signalling that regulates apoptosis in yeast.
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Affiliation(s)
- Campbell W Gourlay
- Department of Molecular Biology and Biotechnology, Firth Court, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
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97
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Abstract
Yeasts as eukaryotic microorganisms with simple, well known and tractable genetics, have long been powerful model systems for studying complex biological phenomena such as the cell cycle or vesicle fusion. Until recently, yeast has been assumed as a cellular 'clean room' to study the interactions and the mechanisms of action of mammalian apoptotic regulators. However, the finding of an endogenous programmed cell death (PCD) process in yeast with an apoptotic phenotype has turned yeast into an 'unclean' but even more powerful model for apoptosis research. Yeast cells appear to possess an endogenous apoptotic machinery including its own regulators and pathway(s). Such machinery may not exactly recapitulate that of mammalian systems but it represents a simple and valuable model which will assist in the future understanding of the complex connections between apoptotic and non-apoptotic mammalian PCD pathways. Following this line of thought and in order to validate and make the most of this promising cell death model, researchers must undoubtedly address the following issues: what are the crucial yeast PCD regulators? How do they play together? What are the cell death pathways shared by yeast and mammalian PCD? Solving these questions is currently the most pressing challenge for yeast cell death researchers.
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Affiliation(s)
- P Ludovico
- Life and Health Research Institute, Health Sciences School, Minho University, Campus de Gualtar, Braga, Portugal.
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98
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Ren Q, Yang H, Rosinski M, Conrad MN, Dresser ME, Guacci V, Zhang Z. Mutation of the cohesin related gene PDS5 causes cell death with predominant apoptotic features in Saccharomyces cerevisiae during early meiosis. Mutat Res 2005; 570:163-73. [PMID: 15708575 DOI: 10.1016/j.mrfmmm.2004.11.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Revised: 10/13/2004] [Accepted: 11/01/2004] [Indexed: 05/01/2023]
Abstract
Pds5p is a cohesin related protein. It is required for maintenance of sister chromatid cohesion in mitosis and meiosis. Here we report that pds5-1 causes cell death in yeast Saccharomyces cerevisiae during early meiosis. The pds5-1 caused cell death possesses characteristics of apoptosis and necrosis, including externalization of phosphatidylserine at cytoplasmic membrane, accumulation of DNA breaks, chromatin condensation and fragmentation, nuclei fragmentation, membrane degeneration and cell size enlargement. Our results also suggest that (1) The defect of DNA repair; (2) The production of reactive oxygen species, in pds5-1 mutant are involved in pds5-1 induced cell death.
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Affiliation(s)
- Qun Ren
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
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99
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Camougrand N, Kissová I, Velours G, Manon S. Uth1p: a yeast mitochondrial protein at the crossroads of stress, degradation and cell death. FEMS Yeast Res 2005; 5:133-40. [PMID: 15489196 DOI: 10.1016/j.femsyr.2004.05.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Revised: 03/30/2004] [Accepted: 05/06/2004] [Indexed: 12/31/2022] Open
Abstract
UTH1 is a yeast aging gene that has been identified on the basis of stress resistance and longer life span of mutants. It was also shown to participate in mitochondrial biogenesis. The absence of Uth1p was found to trigger resistance to autophagy induced by rapamycin. Uth1p is therefore the first mitochondrial protein proven to be required for the autophagic degradation of mitochondria. Since this protein is also involved in yeast cell death induced by heterologous expression of the pro-apoptotic protein Bax, the results are discussed in the light of evidence suggesting a co-regulation of apoptosis and autophagy in mammalian cells.
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Affiliation(s)
- Nadine Camougrand
- Institut de Biochimie et Genetique, Cellulaires du CNRS, UMR5095 CNRS/Université de Bordeaux 2, 1 rue Camille Saint Saens, 33077 Bordeaux Cedex, France.
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100
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Abstract
Apoptosis is a highly regulated cellular suicide program crucial for metazoan development. However, dysfunction of apoptosis also leads to several diseases. Yeast undergoes apoptosis after application of acetic acid, sugar- or salt-stress, plant antifungal peptides, or hydrogen peroxide. Oxygen radicals seem to be key elements of apoptotic execution, conserved during evolution. Furthermore, several yeast orthologues of central metazoan apoptotic regulators have been identified, such as a caspase and a caspase-regulating serine protease. In addition, physiological occurrence of cell death has been detected during aging and mating in yeast. The finding of apoptosis in yeast, other fungi and parasites is not only of great medical relevance but will also help to understand some of the still unknown molecular mechanisms at the core of apoptotic execution.
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Affiliation(s)
- Frank Madeo
- IMB, Karl-Franzens University, Universitätsplatz 2, A-8010 Graz, Austria; Department of Physiological Chemistry, University of Tübingen, Hoppe-Seyler-Str. 4, D-72076 Tübingen, Germany.
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