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Guaragnella N, Ždralević M, Antonacci L, Passarella S, Marra E, Giannattasio S. The role of mitochondria in yeast programmed cell death. Front Oncol 2012; 2:70. [PMID: 22783546 PMCID: PMC3388595 DOI: 10.3389/fonc.2012.00070] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 06/14/2012] [Indexed: 01/02/2023] Open
Abstract
Mammalian apoptosis and yeast programmed cell death (PCD) share a variety of features including reactive oxygen species production, protease activity and a major role played by mitochondria. In view of this, and of the distinctive characteristics differentiating yeast and multicellular organism PCD, the mitochondrial contribution to cell death in the genetically tractable yeast Saccharomyces cerevisiae has been intensively investigated. In this mini-review we report whether and how yeast mitochondrial function and proteins belonging to oxidative phosphorylation, protein trafficking into and out of mitochondria, and mitochondrial dynamics, play a role in PCD. Since in PCD many processes take place over time, emphasis will be placed on an experimental model based on acetic acid-induced PCD (AA-PCD) which has the unique feature of having been investigated as a function of time. As will be described there are at least two AA-PCD pathways each with a multifaceted role played by mitochondrial components, in particular by cytochrome c.
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Affiliation(s)
- Nicoletta Guaragnella
- Institute of Biomembranes and Bioenergetics, National Research Council of Italy,Bari, Italy
| | - Maša Ždralević
- Institute of Biomembranes and Bioenergetics, National Research Council of Italy,Bari, Italy
| | - Lucia Antonacci
- Institute of Biomembranes and Bioenergetics, National Research Council of Italy,Bari, Italy
| | - Salvatore Passarella
- Department of Medicine and Health Sciences, University of Molise,Campobasso, Italy
| | - Ersilia Marra
- Institute of Biomembranes and Bioenergetics, National Research Council of Italy,Bari, Italy
| | - Sergio Giannattasio
- Institute of Biomembranes and Bioenergetics, National Research Council of Italy,Bari, Italy
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52
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Orlandi I, Casatta N, Vai M. Lack of Ach1 CoA-Transferase Triggers Apoptosis and Decreases Chronological Lifespan in Yeast. Front Oncol 2012; 2:67. [PMID: 22754872 PMCID: PMC3386497 DOI: 10.3389/fonc.2012.00067] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 06/11/2012] [Indexed: 11/13/2022] Open
Abstract
ACH1 encodes a mitochondrial enzyme of Saccharomyces cerevisiae endowed with CoA-transferase activity. It catalyzes the CoASH transfer from succinyl-CoA to acetate generating acetyl-CoA. It is known that ACH1 inactivation results in growth defects on media containing acetate as a sole carbon and energy source which are particularly severe at low pH. Here, we show that chronological aging ach1Δ cells which accumulate a high amount of extracellular acetic acid display a reduced chronological lifespan. The faster drop of cell survival is completely abrogated by alleviating the acid stress either by a calorie restricted regimen that prevents acetic acid production or by transferring chronologically aging mutant cells to water. Moreover, the short-lived phenotype of ach1Δ cells is accompanied by reactive oxygen species accumulation, severe mitochondrial damage, and an early insurgence of apoptosis. A similar pattern of endogenous severe oxidative stress is observed when ach1Δ cells are cultured using acetic acid as a carbon source under acidic conditions. On the whole, our data provide further evidence of the role of acetic acid as cell-extrinsic mediator of cell death during chronological aging and highlight a primary role of Ach1 enzymatic activity in acetic acid detoxification which is important for mitochondrial functionality.
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Affiliation(s)
- Ivan Orlandi
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca Milano, Italy
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53
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Farrugia G, Balzan R. Oxidative stress and programmed cell death in yeast. Front Oncol 2012; 2:64. [PMID: 22737670 PMCID: PMC3380282 DOI: 10.3389/fonc.2012.00064] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 06/02/2012] [Indexed: 12/11/2022] Open
Abstract
Yeasts, such as Saccharomyces cerevisiae, have long served as useful models for the study of oxidative stress, an event associated with cell death and severe human pathologies. This review will discuss oxidative stress in yeast, in terms of sources of reactive oxygen species (ROS), their molecular targets, and the metabolic responses elicited by cellular ROS accumulation. Responses of yeast to accumulated ROS include upregulation of antioxidants mediated by complex transcriptional changes, activation of pro-survival pathways such as mitophagy, and programmed cell death (PCD) which, apart from apoptosis, includes pathways such as autophagy and necrosis, a form of cell death long considered accidental and uncoordinated. The role of ROS in yeast aging will also be discussed.
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Affiliation(s)
- Gianluca Farrugia
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of MaltaMsida, Malta
| | - Rena Balzan
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of MaltaMsida, Malta
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54
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Clapp C, Portt L, Khoury C, Sheibani S, Eid R, Greenwood M, Vali H, Mandato CA, Greenwood MT. Untangling the Roles of Anti-Apoptosis in Regulating Programmed Cell Death using Humanized Yeast Cells. Front Oncol 2012; 2:59. [PMID: 22708116 PMCID: PMC3374133 DOI: 10.3389/fonc.2012.00059] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 05/24/2012] [Indexed: 11/13/2022] Open
Abstract
Genetically programmed cell death (PCD) mechanisms, including apoptosis, are important for the survival of metazoans since it allows, among things, the removal of damaged cells that interfere with normal function. Cell death due to PCD is observed in normal processes such as aging and in a number of pathophysiologies including hypoxia (common causes of heart attacks and strokes) and subsequent tissue reperfusion. Conversely, the loss of normal apoptotic responses is associated with the development of tumors. So far, limited success in preventing unwanted PCD has been reported with current therapeutic approaches despite the fact that inhibitors of key apoptotic inducers such as caspases have been developed. Alternative approaches have focused on mimicking anti-apoptotic processes observed in cells displaying increased resistance to apoptotic stimuli. Hormesis and pre-conditioning are commonly observed cellular strategies where sub-lethal levels of pro-apoptotic stimuli lead to increased resistance to higher or lethal levels of stress. Increased expression of anti-apoptotic sequences is a common mechanism mediating these protective effects. The relevance of the latter observation is exemplified by the observation that transgenic mice overexpressing anti-apoptotic genes show significant reductions in tissue damage following ischemia. Thus strategies aimed at increasing the levels of anti-apoptotic proteins, using gene therapy or cell penetrating recombinant proteins are being evaluated as novel therapeutics to decrease cell death following acute periods of cell death inducing stress. In spite of its functional and therapeutic importance, more is known regarding the processes involved in apoptosis than anti-apoptosis. The genetically tractable yeast Saccharomyces cerevisiae has emerged as an exceptional model to study multiple aspects of PCD including the mitochondrial mediated apoptosis observed in metazoans. To increase our knowledge of the process of anti-apoptosis, we screened a human heart cDNA expression library in yeast cells undergoing PCD due to the conditional expression of a mammalian pro-apoptotic Bax cDNA. Analysis of the multiple Bax suppressors identified revealed several previously known as well as a large number of clones representing potential novel anti-apoptotic sequences. The focus of this review is to report on recent achievements in the use of humanized yeast in genetic screens to identify novel stress-induced PCD suppressors, supporting the use of yeast as a unicellular model organism to elucidate anti-apoptotic and cell survival mechanisms.
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Affiliation(s)
- Caitlin Clapp
- Department of Chemistry and Chemical Engineering, Royal Military College Kingston, ON, Canada
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55
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Tulha J, Faria-Oliveira F, Lucas C, Ferreira C. Programmed cell death in Saccharomyces cerevisiae is hampered by the deletion of GUP1 gene. BMC Microbiol 2012; 12:80. [PMID: 22617017 PMCID: PMC3444424 DOI: 10.1186/1471-2180-12-80] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 04/27/2012] [Indexed: 12/28/2022] Open
Abstract
Background During the past years, yeast has been successfully established as a model to study mechanisms of programmed cell death regulation. Saccharomyces cerevisiae commits to cell death showing typical hallmarks of metazoan apoptosis, in response to different stimuli. Gup1p, an O-acyltransferase, is required for several cellular processes that are related to apoptosis development, such as rafts integrity and stability, lipid metabolism including GPI anchor correct remodeling, proper mitochondrial and vacuole function, bud site selection and actin dynamics. Therefore, we hypothesize that apoptotic process would be affected by GUP1 deletion. Results In the present work we used two known apoptosis inducing conditions, chronological aging and acetic acid, to assess several apoptotic markers in gup1∆ mutant strain. We found that this mutant presents a significantly reduced chronological lifespan as compared to Wt and it is also highly sensitive to acetic acid treatment. In addition, it presents extremely high levels of ROS. There were notorious differences on apoptotic markers between Wt and gup1∆ mutant strains, namely on the maintenance of plasma membrane integrity, on the phosphatidylserine externalization, on the depolarization of mitochondrial membrane and on the chromatin condensation. Those suggested that the mutant, under either condition, probably dies of necrosis and not from apoptosis. Conclusions To Gup1p has been assigned an important function on lipid rafts assembly/integrity, lipid metabolism and GPI anchor remodeling. Our results provide, for the first time, the connection of the integrity of yeast lipid rafts and apoptosis induction and/or signaling, giving new insights into the molecular mechanisms underlying this process in yeast.
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Affiliation(s)
- Joana Tulha
- CBMA (Centre of Molecular and Environmental Biology), Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
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56
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Schuhmann H, Adamska I. Deg proteases and their role in protein quality control and processing in different subcellular compartments of the plant cell. PHYSIOLOGIA PLANTARUM 2012; 145:224-34. [PMID: 22008015 DOI: 10.1111/j.1399-3054.2011.01533.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Degradation of periplasmic proteins (Deg)/high temperature requirement A (HtrA) proteases are ATP-independent serine endopeptidases found in almost every organism. Database searches revealed that 16 Deg paralogues are encoded by the genome of Arabidopsis thaliana, six of which were experimentally shown to be located in chloroplasts, one in peroxisomes, one in mitochondria and one in the nucleus. Two more Deg proteases are predicted to reside in chloroplasts, five in mitochondria (one of them with a dual chloroplastidial/mitochondrial localization) and the subcellular location of one protein is uncertain. This review summarizes the current knowledge on the role of Deg proteases in maintaining protein homeostasis and protein processing in various subcompartments of the plant cell. The chloroplast Deg proteases are the best examined so far, especially with respect to their role in the degradation of photodamaged photosynthetic proteins and in biogenesis of photosystem II (PSII). A combined action of thylakoid lumen and stroma Deg proteases in the primary cleavage of photodamaged D1 protein from PSII reaction centre is discussed on the basis of a recently resolved crystal structure of plant Deg1. The peroxisomal Deg protease is a processing enzyme responsible for the cleavage of N-terminal peroxisomal targeting signals (PTSs). A. thaliana mutants lacking this enzyme show reduced peroxisomal β-oxidation, indicating for the first time the impact of protein processing on peroxisomal functions in plants. Much less data is available for mitochondrial and nuclear Deg proteases. Based on the available expression data we hypothesize a role in general protein quality control and during acquired heat resistance.
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Affiliation(s)
- Holger Schuhmann
- Department of Plant Biology, University of Konstanz, D-78457 Konstanz, Germany
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57
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Barbosa AD, Graça J, Mendes V, Chaves SR, Amorim MA, Mendes MV, Moradas-Ferreira P, Côrte-Real M, Costa V. Activation of the Hog1p kinase in Isc1p-deficient yeast cells is associated with mitochondrial dysfunction, oxidative stress sensitivity and premature aging. Mech Ageing Dev 2012; 133:317-30. [PMID: 22445853 DOI: 10.1016/j.mad.2012.03.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 03/02/2012] [Accepted: 03/09/2012] [Indexed: 10/28/2022]
Abstract
The Saccharomyces cerevisiae Isc1p, an orthologue of mammalian neutral sphingomyelinase 2, plays a key role in mitochondrial function, oxidative stress resistance and chronological lifespan. Isc1p functions upstream of the ceramide-activated protein phosphatase Sit4p through the modulation of ceramide levels. Here, we show that both ceramide and loss of Isc1p lead to the activation of Hog1p, the MAPK of the high osmolarity glycerol (HOG) pathway that is functionally related to mammalian p38 and JNK. The hydrogen peroxide sensitivity and premature aging of isc1Δ cells was partially suppressed by HOG1 deletion. Notably, Hog1p activation mediated the mitochondrial dysfunction and catalase A deficiency associated with oxidative stress sensitivity and premature aging of isc1Δ cells. Downstream of Hog1p, Isc1p deficiency activated the cell wall integrity (CWI) pathway. Deletion of the SLT2 gene, which encodes for the MAPK of the CWI pathway, was lethal in isc1Δ cells and this mutant strain was hypersensitive to cell wall stress. However, the phenotypes of isc1Δ cells were not associated with cell wall defects. Our findings support a role for Hog1p in the regulation of mitochondrial function and suggest that constitutive activation of Hog1p is deleterious for isc1Δ cells under oxidative stress conditions and during chronological aging.
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Affiliation(s)
- António Daniel Barbosa
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
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58
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Nma111p, the pro-apoptotic HtrA-like nuclear serine protease in Saccharomyces cerevisiae: a short survey. Biochem Soc Trans 2012; 39:1499-501. [PMID: 21936841 DOI: 10.1042/bst0391499] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The baker's yeast, Saccharomyces cerevisiae, is also capable of undergoing programmed cell death or apoptosis, for example in response to viral infection as well as during chronological and replicative aging. Intrinsically, programmed cell death in yeast can be induced by, for example, H2O2, acetic acid or the mating-type pheromone. A number of evolutionarily conserved apoptosis-regulatory proteins have been identified in yeast, one of which is the HtrA (high-temperature requirement A)-like serine protease Nma111p (Nma is nuclear mediator of apoptosis). Nma111p is a nuclear serine protease of the HtrA family, which targets Bir1p, the only known inhibitor-of-apoptosis protein in yeast. Nma111p mediates apoptosis in a serine-protease-dependent manner and exhibits its activity exclusively in the nucleus. How the activity of Nma111p is regulated has remained largely elusive, but some evidence points to a control by phosphorylation. Current knowledge of Nma111p's function in apoptosis will be discussed in the present review.
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59
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Abstract
Most of the studies on cell proliferation examine the control of gene expression by specific transcription factors that act on transcriptional initiation. In the last few years, it became evident that mRNA stability/turnover provides an important mechanism for post-transcriptional control of gene expression. In eukaryotes, mRNAs are mainly degraded after deadenylation by decapping and exosome pathways. Mechanisms of mRNA surveillance comprise deadenylation-independent pathways such as NMD (nonsense-mediated decay), when mRNAs harbour a PTC (premature termination codon), NSD (non-stop decay, when mRNAs lack a termination codon, and NGD (no-go decay), when mRNA translation elongation stalls. Many proteins involved in these processes are conserved from bacteria to yeast and humans. Recent papers showed the involvement of proteins deputed to decapping in controlling cell proliferation, virus replication and cell death. In this paper, we will review the newest findings in this field.
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60
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Abstract
A concerted balance between proliferation and apoptosis is essential to the survival of multicellular organisms. Thus, apoptosis per se, although it is a destructive process leading to the death of single cells, also serves as a pro-survival mechanism pro-survival mechanism that ensures healthy organismal development and acts as a life-prolonging or anti-aging anti-aging program. The discovery that yeast also possess a functional and, in many cases, highly conserved apoptotic machinery has made it possible to study the relationships between aging and apoptosis in depth using a well-established genetic system and the powerful tools available to yeast researchers for investigating complex physiological and cytological interactions. The aging process of yeast, be it replicative replicative or chronological chronological aging, is closely related to apoptosis, although it remains unclear whether apoptosis is a causal feature of the aging process or vice versa. Nevertheless, experimental results obtained during the past several years clearly demonstrate that yeast serve as a powerful and versatile experimental system for understanding the interconnections between these two fundamentally important cellular and physiological pathways.
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Affiliation(s)
- Peter Laun
- Division of Genetics, Department of Cell Biology, University of Salzburg, Salzburg, Austria,
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61
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Kong F, Liu X, Huang N, Zhou F, Ge L. Aif1p inhibits development of fluconazole resistance in yeast. ANN MICROBIOL 2011. [DOI: 10.1007/s13213-011-0399-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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62
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Apoptosis-like programmed cell death in the grey mould fungus Botrytis cinerea: genes and their role in pathogenicity. Biochem Soc Trans 2011; 39:1493-8. [DOI: 10.1042/bst0391493] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A considerable number of fungal homologues of human apoptotic genes have been identified in recent years. Nevertheless, we are far from being able to connect the different pieces and construct a primary structure of the fungal apoptotic regulatory network. To get a better picture of the available fungal components, we generated an automatic search protocol that is based on protein sequences together with a domain-centred approach. We used this protocol to search all the available fungal databases for domains and homologues of human apoptotic proteins. Among all known apoptotic domains, only the BIR [baculovirus IAP (inhibitor of apoptosis protein) repeat] domain was found in fungi. A single protein with one or two BIR domains is present in most (but not all) fungal species. We isolated the BIR-containing protein from the grey mould fungus Botrytis cinerea and determined its role in apoptosis and pathogenicity. We also isolated and analysed BcNMA, a homologue of the yeast NMA11 gene. Partial knockout or overexpression strains of BcBIR1 confirmed that BcBir1 is anti-apoptotic and this activity was assigned to the N′-terminal part of the protein. Plant infection assays showed that the fungus undergoes massive PCD (programmed cell death) during early stages of infection. Further studies showed that fungal virulence was fully correlated with the ability of the fungus to cope with plant-induced PCD. Together, our result show that BcBir1 is a major regulator of PCD in B. cinerea and that proper regulation of the host-induced PCD is essential for pathogenesis in this and other similar fungal pathogens.
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63
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Teng X, Cheng WC, Qi B, Yu TX, Ramachandran K, Boersma MD, Hattier T, Lehmann PV, Pineda FJ, Hardwick JM. Gene-dependent cell death in yeast. Cell Death Dis 2011; 2:e188. [PMID: 21814286 PMCID: PMC3181418 DOI: 10.1038/cddis.2011.72] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Caspase-dependent apoptotic cell death has been extensively studied in cultured cells and during embryonic development, but the existence of analogous molecular pathways in single-cell species is uncertain. This has reduced enthusiasm for applying the advanced genetic tools available for yeast to study cell death regulation. However, partial characterization in mammals of additional genetically encoded cell death mechanisms, which lead to a range of dying cell morphologies and necrosis, suggests potential applications for yeast genetics. In this light, we revisited the topic of gene-dependent cell death in yeast to determine the prevalence of yeast genes with the capacity to contribute to cell-autonomous death. We developed a rigorous strategy by allowing sufficient time for gene-dependent events to occur, but insufficient time to evolve new populations, and applied this strategy to the Saccharomyces cerevisiae gene knockout collection. Unlike sudden heat shock, a ramped heat stimulus delivered over several minutes with a thermocycler, coupled with assessment of viability by automated counting of microscopic colonies revealed highly reproducible gene-specific survival phenotypes, which typically persist under alternative conditions. Unexpectedly, we identified over 800 yeast knockout strains that exhibit significantly increased survival following insult, implying that these genes can contribute to cell death. Although these death mechanisms are yet uncharacterized, this study facilitates further exploration.
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Affiliation(s)
- X Teng
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD, USA
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64
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Braun RJ, Sommer C, Carmona-Gutierrez D, Khoury CM, Ring J, Büttner S, Madeo F. Neurotoxic 43-kDa TAR DNA-binding protein (TDP-43) triggers mitochondrion-dependent programmed cell death in yeast. J Biol Chem 2011; 286:19958-72. [PMID: 21471218 PMCID: PMC3103370 DOI: 10.1074/jbc.m110.194852] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 04/04/2011] [Indexed: 12/12/2022] Open
Abstract
Pathological neuronal inclusions of the 43-kDa TAR DNA-binding protein (TDP-43) are implicated in dementia and motor neuron disorders; however, the molecular mechanisms of the underlying cell loss remain poorly understood. Here we used a yeast model to elucidate cell death mechanisms upon expression of human TDP-43. TDP-43-expressing cells displayed markedly increased markers of oxidative stress, apoptosis, and necrosis. Cytotoxicity was dose- and age-dependent and was potentiated upon expression of disease-associated variants. TDP-43 was localized in perimitochondrial aggregate-like foci, which correlated with cytotoxicity. Although the deleterious effects of TDP-43 were significantly decreased in cells lacking functional mitochondria, cell death depended neither on the mitochondrial cell death proteins apoptosis-inducing factor, endonuclease G, and cytochrome c nor on the activity of cell death proteases like the yeast caspase 1. In contrast, impairment of the respiratory chain attenuated the lethality upon TDP-43 expression with a stringent correlation between cytotoxicity and the degree of respiratory capacity or mitochondrial DNA stability. Consistently, an increase in the respiratory capacity of yeast resulted in enhanced TDP-43-triggered cytotoxicity, oxidative stress, and cell death markers. These data demonstrate that mitochondria and oxidative stress are important to TDP-43-triggered cell death in yeast and may suggest a similar role in human TDP-43 pathologies.
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Affiliation(s)
- Ralf J. Braun
- From the Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria and
- Institute of Cell Biology, University of Bayreuth, 95440 Bayreuth, Germany
| | - Cornelia Sommer
- From the Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria and
| | - Didac Carmona-Gutierrez
- From the Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria and
| | - Chamel M. Khoury
- From the Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria and
| | - Julia Ring
- From the Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria and
| | - Sabrina Büttner
- From the Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria and
| | - Frank Madeo
- From the Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria and
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65
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Finkelshtein A, Shlezinger N, Bunis O, Sharon A. Botrytis cinerea BcNma is involved in apoptotic cell death but not in stress adaptation. Fungal Genet Biol 2011; 48:621-30. [DOI: 10.1016/j.fgb.2011.01.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 01/16/2011] [Accepted: 01/18/2011] [Indexed: 11/28/2022]
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66
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Carmona-Gutiérrez D, Bauer MA, Ring J, Knauer H, Eisenberg T, Büttner S, Ruckenstuhl C, Reisenbichler A, Magnes C, Rechberger GN, Birner-Gruenberger R, Jungwirth H, Fröhlich KU, Sinner F, Kroemer G, Madeo F. The propeptide of yeast cathepsin D inhibits programmed necrosis. Cell Death Dis 2011; 2:e161. [PMID: 21593793 PMCID: PMC3122122 DOI: 10.1038/cddis.2011.43] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The lysosomal endoprotease cathepsin D (CatD) is an essential player in general protein turnover and specific peptide processing. CatD-deficiency is associated with neurodegenerative diseases, whereas elevated CatD levels correlate with tumor malignancy and cancer cell survival. Here, we show that the CatD ortholog of the budding yeast Saccharomyces cerevisiae (Pep4p) harbors a dual cytoprotective function, composed of an anti-apoptotic part, conferred by its proteolytic capacity, and an anti-necrotic part, which resides in the protein's proteolytically inactive propeptide. Thus, deletion of PEP4 resulted in both apoptotic and necrotic cell death during chronological aging. Conversely, prolonged overexpression of Pep4p extended chronological lifespan specifically through the protein's anti-necrotic function. This function, which triggered histone hypoacetylation, was dependent on polyamine biosynthesis and was exerted via enhanced intracellular levels of putrescine, spermidine and its precursor S-adenosyl-methionine. Altogether, these data discriminate two pro-survival functions of yeast CatD and provide first insight into the physiological regulation of programmed necrosis in yeast.
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67
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A new principle of oligomerization of plant DEG7 protease based on interactions of degenerated protease domains. Biochem J 2011; 435:167-74. [PMID: 21247409 PMCID: PMC3194040 DOI: 10.1042/bj20101613] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Deg/HtrA proteases are a large group of ATP-independent serine endoproteases found in almost every organism. Their usual domain arrangement comprises a trypsin-type protease domain and one or more PDZ domains. All Deg/HtrA proteases form homo-oligomers with trimers as the basic unit, where the active protease domain mediates the interaction between individual monomers. Among the members of the Deg/HtrA protease family, the plant protease DEG7 is unique since it contains two protease domains (one active and one degenerated) and four PDZ domains. In the present study, we investigated the oligomerization behaviour of this unusual protease using yeast two-hybrid analysis in vivo and with recombinant protein in vitro. We show that DEG7 forms trimeric complexes, but in contrast with other known Deg/HtrA proteases, it shows a new principle of oligomerization, where trimerization is based on the interactions between degenerated protease domains. We propose that, during evolution, a duplicated active protease domain degenerated and specialized in protein-protein interaction and complex formation.
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68
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Ruckenstuhl C, Carmona-Gutierrez D, Madeo F. The sweet taste of death: glucose triggers apoptosis during yeast chronological aging. Aging (Albany NY) 2011; 2:643-9. [PMID: 21076182 PMCID: PMC2993794 DOI: 10.18632/aging.100223] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
As time goes by, a postmitotic cell ages following a degeneration process ultimately ending in cell death. This phenomenon is evolutionary conserved and present in unicellular eukaryotes as well, making the yeast chronological aging system an appreciated model. Here, single cells die in a programmed fashion (both by apoptosis and necrosis) for the benefit of the whole population. Besides its meaning for aging and cell death research, age-induced programmed cell death represents the first experimental proof for the so-called group selection theory: Apoptotic genes became selected during evolution because of the benefits they might render to the whole cell culture and not to the individual cell. Many anti‐aging stimuli have been discovered in the yeast chronological aging system and have afterwards been confirmed in higher cells or organisms. New work from the Burhans group (this issue) now demonstrates that glucose signaling has a progeriatric effect on chronologically aged yeast cells: Glucose administration results in a diminished efficacy of cells to enter quiescence, finally causing superoxide‐mediated replication stress and apoptosis.
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69
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Abdelwahid E, Rolland S, Teng X, Conradt B, Hardwick JM, White K. Mitochondrial involvement in cell death of non-mammalian eukaryotes. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1813:597-607. [PMID: 20950655 PMCID: PMC3033473 DOI: 10.1016/j.bbamcr.2010.10.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 09/29/2010] [Accepted: 10/04/2010] [Indexed: 12/28/2022]
Abstract
Although mitochondria are essential organelles for long-term survival of eukaryotic cells, recent discoveries in biochemistry and genetics have advanced our understanding of the requirements for mitochondria in cell death. Much of what we understand about cell death is based on the identification of conserved cell death genes in Drosophila melanogaster and Caenorhabditis elegans. However, the role of mitochondria in cell death in these models has been much less clear. Considering the active role that mitochondria play in apoptosis in mammalian cells, the mitochondrial contribution to cell death in non-mammalian systems has been an area of active investigation. In this article, we review the current research on this topic in three non-mammalian models, C. elegans, Drosophila, and Saccharomyces cerevisiae. In addition, we discuss how non-mammalian models have provided important insight into the mechanisms of human disease as they relate to the mitochondrial pathway of cell death. The unique perspective derived from each of these model systems provides a more complete understanding of mitochondria in programmed cell death. This article is part of a Special Issue entitled Mitochondria: the deadly organelle.
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Affiliation(s)
- Eltyeb Abdelwahid
- Cutaneous Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Building 149, 13th Street, Charlestown, MA 02129, USA
| | - Stephane Rolland
- Department of Genetics, Norris Cotton Cancer Center, Dartmouth Medical School, Hanover, NH 03755, USA
| | - Xinchen Teng
- Departments of Molecular Microbiology and Immunology, and Pharmacology and Molecular Sciences, Johns Hopkins University, Schools of Public Health and Medicine, Baltimore, MD 21205, USA
| | - Barbara Conradt
- Department of Genetics, Norris Cotton Cancer Center, Dartmouth Medical School, Hanover, NH 03755, USA
| | - J. Marie Hardwick
- Departments of Molecular Microbiology and Immunology, and Pharmacology and Molecular Sciences, Johns Hopkins University, Schools of Public Health and Medicine, Baltimore, MD 21205, USA
| | - Kristin White
- Cutaneous Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Building 149, 13th Street, Charlestown, MA 02129, USA
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70
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Severin FF, Skulachev VP. Programmed cell death as a target to interrupt the aging program. ADVANCES IN GERONTOLOGY 2011. [DOI: 10.1134/s2079057011010139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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71
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Abstract
A canonical regulatory pathway involving the members of the Bcl-2 and caspase families has been established to regulate developmental apoptosis in nematodes and flies. However, mutant mice that have major deficiencies in this apoptosis pathway show only relatively minor developmental defects. Recent revelations indicate that multiple mechanisms are involved in regulating cell death during mammalian development, tissue homeostasis, and pathological cell loss. Here, we critically evaluate the evidence demonstrating the existence of alternative cell death mechanisms, including apoptosis of lower organisms in the absence of canonical apoptosis mediators, autophagic cell death, necroptosis, elimination by shedding, keratinocyte death by cornification, and cell-cell cannibalism by entosis. The physiological relevance of alternative cell death mechanisms as primary and backup mechanisms is discussed.
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Affiliation(s)
- Junying Yuan
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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72
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Kovaleva MV, Sukhanova EI, Trendeleva TA, Popova KM, Zylkova MV, Uralskaya LA, Zvyagilskaya RA. Induction of permeability of the inner membrane of yeast mitochondria. BIOCHEMISTRY (MOSCOW) 2010; 75:297-303. [PMID: 20370607 DOI: 10.1134/s0006297910030053] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The current view on apoptosis is given, with a special emphasis placed on apoptosis in yeasts. Induction of a nonspecific permeability transition pore (mPTP) in mammalian and yeast mitochondria is described, particularly in mitochondria from Yarrowia lipolytica and Dipodascus (Endomyces) magnusii yeasts, which are aerobes possessing the fully competent respiratory chain with all three points of energy conservation and well-structured mitochondria. They were examined for their ability to induce an elevated permeability transition of the inner mitochondrial membrane, being subjected to virtually all conditions known to induce the mPTP in animal mitochondria. Yeast mitochondria do not form Ca2+-dependent pores, neither the classical Ca2+/P(i)-dependent, cyclosporin A-sensitive pore even under de-energization of mitochondria or depletion of the intramitochondrial nucleotide pools, nor a pore induced in mammalian mitochondria upon concerted action of moderate Ca2+ concentrations (in the presence of the Ca2+ ionophore ETH129) and saturated fatty acids. No pore formation was found in yeast mitochondria in the presence of elevated phosphate concentrations at acidic pH values. It is concluded that the permeability transition in yeast mitochondria is not coupled with Ca2+ uptake and is differently regulated compared to the mPTP of animal mitochondria.
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Affiliation(s)
- M V Kovaleva
- Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia
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73
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Palermo V, Falcone C, Calvani M, Mazzoni C. Acetyl-L-carnitine protects yeast cells from apoptosis and aging and inhibits mitochondrial fission. Aging Cell 2010; 9:570-9. [PMID: 20550520 DOI: 10.1111/j.1474-9726.2010.00587.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In this work we report that carnitines, in particular acetyl-l-carnitine (ALC), are able to prolong the chronological aging of yeast cells during the stationary phase. Lifespan extension is significantly reduced in yca1 mutants as well in rho(0) strains, suggesting that the protective effects pass through the Yca1 caspase and mitochondrial functions. ALC can also prevent apoptosis in pro-apoptotic mutants, pointing to the importance of mitochondrial functions in regulating yeast apoptosis and aging. We also demonstrate that ALC attenuates mitochondrial fission in aged yeast cells, indicating a correlation between its protective effect and this process. Our findings suggest that ALC, used as therapeutic for stroke, myocardial infarction and neurodegenerative diseases, besides the well-known anti-oxidant effects, might exert protective effects also acting on mitochondrial morphology.
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Affiliation(s)
- Vanessa Palermo
- Department of Cell and Developmental Biology, University of Rome, Rome, Italy
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74
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Walter D, Matter A, Fahrenkrog B. Bre1p-mediated histone H2B ubiquitylation regulates apoptosis in Saccharomyces cerevisiae. J Cell Sci 2010; 123:1931-9. [DOI: 10.1242/jcs.065938] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BRE1 encodes an E3 ubiquitin protein ligase that is required for the ubiquitylation of histone H2B at lysine 123 (K123). Ubiquitylation of this histone residue is involved in a variety of cellular processes including gene activation and gene silencing. Abolishing histone H2B ubiquitylation also confers X-ray sensitivity and abrogates checkpoint activation after DNA damage. Here we show that Saccharomyces cerevisiae Bre1p exhibits anti-apoptotic activity in yeast and that this is linked to histone H2B ubiquitylation. We found that enhanced levels of Bre1p protect from hydrogen-peroxide-induced cell death, whereas deletion of BRE1 enhances cell death. Moreover, cells lacking Bre1p show reduced lifespan during chronological ageing, a physiological apoptotic condition in yeast. Importantly, the resistance against apoptosis is conferred by histone H2B ubiquitylation mediated by the E3 ligase activity of Bre1p. Furthermore, we found that the death of Δbre1 cells depends on the yeast caspase Yca1p, because Δbre1 cells exhibit increased caspase activity when compared with wild-type cells, and deletion of YCA1 leads to reduced apoptosis sensitivity of cells lacking Bre1p.
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Affiliation(s)
- David Walter
- M. E. Müller Institute for Structural Biology, Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | - Anja Matter
- M. E. Müller Institute for Structural Biology, Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| | - Birthe Fahrenkrog
- M. E. Müller Institute for Structural Biology, Biozentrum, University of Basel, CH-4056 Basel, Switzerland
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75
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Carmona-Gutierrez D, Ruckenstuhl C, Bauer MA, Eisenberg T, Büttner S, Madeo F. Cell death in yeast: growing applications of a dying buddy. Cell Death Differ 2010; 17:733-4. [PMID: 20383156 DOI: 10.1038/cdd.2010.10] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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76
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Signaling mechanisms of apoptosis-like programmed cell death in unicellular eukaryotes. Comp Biochem Physiol B Biochem Mol Biol 2010; 155:341-53. [DOI: 10.1016/j.cbpb.2010.01.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 01/19/2010] [Accepted: 01/23/2010] [Indexed: 11/18/2022]
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77
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Rockenfeller P, Madeo F. Ageing and eating. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:499-506. [DOI: 10.1016/j.bbamcr.2010.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 12/24/2009] [Accepted: 01/04/2010] [Indexed: 01/09/2023]
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78
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Chahomchuen T, Akiyama K, Sekito T, Sugimoto N, Okabe M, Nishimoto S, Sugahara T, Kakinuma Y. Tributyltin induces Yca1p-dependent cell death of yeast Saccharomyces cerevisiae. J Toxicol Sci 2010; 34:541-5. [PMID: 19797862 DOI: 10.2131/jts.34.541] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Tributyltin chloride (TBT), an environmental pollutant, is toxic to a variety of eukaryotic and prokaryotic organisms. Although it has been reported that TBT induces apoptotic cell death in mammalian, the action of TBT on eukaryotic microorganisms has not yet been fully investigated. In this study we examined the mechanism involved in cell death caused by TBT exposure in Saccharomyces cerevisiae. The median lethal concentration of TBT was 10 microM for the parent strain BY4741 and 3 microM for the pdr5Delta mutant defective in a major multidrug transporter, respectively. Fluorescence microscopic observations revealed nuclear condensation and chromatin fragmentation in cells treated with TBT indicating that cells underwent an apoptosis-like cell dearth. TBT-induced cell death was suppressed by deletion of the yca1 gene encoding a homologue of the mammalian caspase. In parallel, reactive oxygen species (ROS) were produced by TBT. These results suggest that TBT induces apoptosis-like cell death in yeast via an Yca1p-dependent pathway possibly downstream of the ROS production. This is the first report on TBT-induced apoptotic cell death in yeast.
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79
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80
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Eisenberg T, Carmona-Gutierrez D, Büttner S, Tavernarakis N, Madeo F. Necrosis in yeast. Apoptosis 2010; 15:257-68. [DOI: 10.1007/s10495-009-0453-4] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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81
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Belanger KD, Walter D, Henderson TA, Yelton AL, O'Brien TG, Belanger KG, Geier SJ, Fahrenkrog B. Nuclear localisation is crucial for the proapoptotic activity of the HtrA-like serine protease Nma111p. J Cell Sci 2009; 122:3931-41. [DOI: 10.1242/jcs.056887] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Programmed cell death is induced by the activation of a subset of intracellular proteins in response to specific extra- and intracellular signals. In the yeast Saccharomyces cerevisiae, Nma111p functions as a nuclear serine protease that is necessary for apoptosis under cellular stress conditions, such as elevated temperature or treatment of cells with hydrogen peroxide to induce cell death. We have examined the role of nuclear protein import in the function of Nma111p in apoptosis. Nma111p contains two small clusters of basic residues towards its N-terminus, both of which are necessary for efficient translocation into the nucleus. Nma111p does not shuttle between the nucleus and cytoplasm during either normal growth conditions or under environmental stresses that induce apoptosis. The N-terminal half of Nma111p is sufficient to provide the apoptosis-inducing activity of the protein, and the nuclear-localisation signal (NLS) sequences and catalytic serine 235 are both necessary for this function. We provide compelling evidence that intranuclear Nma111p activity is necessary for apoptosis in yeast.
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Affiliation(s)
- Kenneth D. Belanger
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - David Walter
- M. E. Muller Institute for Structural Biology, Biozentrum, University of Basel, Klingelbergstr. 70, 4056 Basel, Switzerland
| | - Tracey A. Henderson
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Allison L. Yelton
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Travis G. O'Brien
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Karyn G. Belanger
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Susan J. Geier
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Birthe Fahrenkrog
- M. E. Muller Institute for Structural Biology, Biozentrum, University of Basel, Klingelbergstr. 70, 4056 Basel, Switzerland
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82
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Huesgen PF, Schuhmann H, Adamska I. Deg/HtrA proteases as components of a network for photosystem II quality control in chloroplasts and cyanobacteria. Res Microbiol 2009; 160:726-32. [PMID: 19732828 DOI: 10.1016/j.resmic.2009.08.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 08/10/2009] [Accepted: 08/11/2009] [Indexed: 11/16/2022]
Abstract
Organisms that perform oxygenic photosynthesis are subjected to photoinhibition of their photosynthetic function when exposed to excessive illumination. The main target of photoinhibition is the D1 protein in the reaction center of the photosystem II complex. Rapid degradation of photodamaged D1 protein and its replacement by a de novo synthesized functional copy represent an important repair mechanism crucial for cell survival under light stress conditions. This review summarizes the literature on the ATP-independent Deg/HtrA family of serine endopeptidases in cyanobacteria and chloroplasts of higher plants, and discusses their role in D1 protein degradation. We propose that Deg/HtrA proteases are part of a larger network of enzymes that ensure protein quality control, including photosystem II, in plants and cyanobacteria.
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Affiliation(s)
- Pitter F Huesgen
- Department of Plant Physiology and Biochemistry, University of Konstanz, Universitätsstrasse 10, D-78457 Konstanz, Germany
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83
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Kovaleva MV, Sukhanova EI, Trendeleva TA, Zyl'kova MV, Ural'skaya LA, Popova KM, Saris NEL, Zvyagilskaya RA. Induction of a non-specific permeability transition in mitochondria from Yarrowia lipolytica and Dipodascus (Endomyces) magnusii yeasts. J Bioenerg Biomembr 2009; 41:239-49. [PMID: 19609656 DOI: 10.1007/s10863-009-9227-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 06/15/2009] [Indexed: 10/20/2022]
Abstract
In this study we used tightly-coupled mitochondria from Yarrowia lipolytica and Dipodascus (Endomyces) magnusii yeasts, possessing a respiratory chain with the usual three points of energy conservation. High-amplitude swelling and collapse of the membrane potential were used as parameters for demonstrating induction of the mitochondrial permeability transition due to opening of a pore (mPTP). Mitochondria from Y. lipolytica, lacking a natural mitochondrial Ca(2+) uptake pathway, and from D. magnusii, harboring a high-capacitive, regulated mitochondrial Ca(2+) transport system (Bazhenova et al. J Biol Chem 273:4372-4377, 1998a; Bazhenova et al. Biochim Biophys Acta 1371:96-100, 1998b; Deryabina and Zvyagilskaya Biochemistry (Moscow) 65:1352-1356, 2000; Deryabina et al. J Biol Chem 276:47801-47806, 2001) were very resistant to Ca(2+) overload. However, exposure of yeast mitochondria to 50-100 microM Ca(2+) in the presence of the Ca(2+) ionophore ETH129 induced collapse of the membrane potential, possibly due to activation of the fatty acid-dependent Ca(2+)/nH(+)-antiporter, with no classical mPTP induction. The absence of response in yeast mitochondria was not simply due to structural limitations, since large-amplitude swelling occurred in the presence of alamethicin, a hydrophobic, helical peptide, forming voltage-sensitive ion channels in lipid membranes. Ca(2+)- ETH129-induced activation of the Ca(2+)/H(+)-antiport system was inhibited and prevented by bovine serum albumin, and partially by inorganic phosphate and ATP. We subjected yeast mitochondria to other conditions known to induce the permeability transition in animal mitochondria, i.e., Ca(2+) overload (in the presence of ETH129) combined with palmitic acid (Mironova et al. J Bioenerg Biomembr 33:319-331, 2001; Sultan and Sokolove Arch Biochem Biophys 386:37-51, 2001), SH-reagents, carboxyatractyloside (an inhibitor of the ADP/ATP translocator), depletion of intramitochondrial adenine nucleotide pools, deenergization of mitochondria, and shifting to acidic pH values in the presence of high phosphate concentrations. None of the above-mentioned substances or conditions induced a mPTP-like pore. It is thus evident that the permeability transition in yeast mitochondria is not coupled with Ca(2+) uptake and is differently regulated compared to the mPTP of animal mitochondria.
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Affiliation(s)
- Mariya V Kovaleva
- A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, Russia
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84
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Guérin R, Beauregard PB, Leroux A, Rokeach LA. Calnexin regulates apoptosis induced by inositol starvation in fission yeast. PLoS One 2009; 4:e6244. [PMID: 19606215 PMCID: PMC2705804 DOI: 10.1371/journal.pone.0006244] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 06/08/2009] [Indexed: 12/21/2022] Open
Abstract
Inositol is a precursor of numerous phospholipids and signalling molecules essential for the cell. Schizosaccharomyces pombe is naturally auxotroph for inositol as its genome does not have a homologue of the INO1 gene encoding inositol-1-phosphate synthase, the enzyme responsible for inositol biosynthesis. In this work, we demonstrate that inositol starvation in S. pombe causes cell death with apoptotic features. This apoptotic death is dependent on the metacaspase Pca1p and is affected by the UPR transducer Ire1p. Previously, we demonstrated that calnexin is involved in apoptosis induced by ER stress. Here, we show that cells expressing a lumenal version of calnexin exhibit a 2-fold increase in the levels of apoptosis provoked by inositol starvation. This increase is reversed by co-expression of a calnexin mutant spanning the transmembrane domain and C-terminal cytosolic tail. Coherently, calnexin is physiologically cleaved at the end of its lumenal domain, under normal growth conditions when cells approach stationary phase. This cleavage suggests that the two naturally produced calnexin fragments are needed to continue growth into stationary phase and to prevent cell death. Collectively, our observations indicate that calnexin takes part in at least two apoptotic pathways in S. pombe, and suggest that the cleavage of calnexin has regulatory roles in apoptotic processes involving calnexin.
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Affiliation(s)
- Renée Guérin
- Department of Biochemistry, Université de Montréal, Montréal, Québec, Canada
| | | | - Alexandre Leroux
- Department of Biochemistry, Université de Montréal, Montréal, Québec, Canada
| | - Luis A. Rokeach
- Department of Biochemistry, Université de Montréal, Montréal, Québec, Canada
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85
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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: 4.2] [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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86
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Madeo F, Carmona-Gutierrez D, Ring J, Büttner S, Eisenberg T, Kroemer G. Caspase-dependent and caspase-independent cell death pathways in yeast. Biochem Biophys Res Commun 2009; 382:227-31. [DOI: 10.1016/j.bbrc.2009.02.117] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 02/21/2009] [Indexed: 01/31/2023]
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87
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Sharon A, Finkelstein A, Shlezinger N, Hatam I. Fungal apoptosis: function, genes and gene function. FEMS Microbiol Rev 2009; 33:833-54. [PMID: 19416362 DOI: 10.1111/j.1574-6976.2009.00180.x] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Cells of all living organisms are programmed to self-destruct under certain conditions. The most well known form of programmed cell death is apoptosis, which is essential for proper development in higher eukaryotes. In fungi, apoptotic-like cell death occurs naturally during aging and reproduction, and can be induced by environmental stresses and exposure to toxic metabolites. The core apoptotic machinery in fungi is similar to that in mammals, but the apoptotic network is less complex and of more ancient origin. Only some of the mammalian apoptosis-regulating proteins have fungal homologs, and the number of protein families is drastically reduced. Expression in fungi of animal proteins that do not have fungal homologs often affects apoptosis, suggesting functional conservation of these components despite the absence of protein-sequence similarity. Functional analysis of Saccharomyces cerevisiae apoptotic genes, and more recently of those in some filamentous species, has revealed partial conservation, along with substantial differences in function and mode of action between fungal and human proteins. It has been suggested that apoptotic proteins might be suitable targets for novel antifungal treatments. However, implementation of this approach requires a better understanding of fungal apoptotic networks and identification of the key proteins regulating apoptotic-like cell death in fungi.
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Affiliation(s)
- Amir Sharon
- Department of Plant Sciences, Tel Aviv University, Tel Aviv, Israel.
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88
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Lisa-Santamaría P, Neiman AM, Cuesta-Marbán Á, Mollinedo F, Revuelta JL, Jiménez A. Human initiator caspases trigger apoptotic and autophagic phenotypes in Saccharomyces cerevisiae. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1793:561-71. [PMID: 19166881 PMCID: PMC2647587 DOI: 10.1016/j.bbamcr.2008.12.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 12/17/2008] [Accepted: 12/18/2008] [Indexed: 01/07/2023]
Abstract
Caspases are a family of proteases that participate in the progression and execution of the apoptotic program. However, regulation of the caspase activation and their substrates has not yet been fully elucidated. Here we explore the effect of the ectopic expression of the human initiator caspases-8 and -10 in Saccharomyces cerevisiae. Our results showed that the expression of human CASP10 and CASP8 triggers certain apoptotic markers such as a massive production of reactive oxygen species (ROS), chromatin condensation and phosphatidylserine externalization, finally leading to cell death. In response to hydroxyurea (HU), yeast cells expressing caspase-10 did not reduce the replication of DNA and escaped to the intra-S checkpoint of the cell cycle. In addition, caspase-10 expression induced yeast vacuolization and a vacuole-associated phenotype resembling autophagy. Other intracellular alterations such as disorganization of the actin cytoskeleton, cell wall damage, and aberrations within the endoplasmic reticulum lumen were also associated with caspase-10 expression. Furthermore, caspase-induced cell death was completely dependent on the proteolytic activation of the enzyme but, in contrast, was not dependent on either of the endogenous yeast apoptotic proteins Aif1 and Mca1 or the mitochondria.
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Affiliation(s)
- Patricia Lisa-Santamaría
- Instituto de Microbiología Bioquímica y Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, Campus Miguel de Unamuno, E-37007 Salamanca, Spain
| | - Aaron M. Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | - Álvaro Cuesta-Marbán
- Centro de Investigación del Cáncer, Instituto de Biología Molecular y Celular del Cáncer, CSIC/Universidad de Salamanca, Campus Miguel de Unamuno, E-37007 Salamanca, Spain
| | - Faustino Mollinedo
- Centro de Investigación del Cáncer, Instituto de Biología Molecular y Celular del Cáncer, CSIC/Universidad de Salamanca, Campus Miguel de Unamuno, E-37007 Salamanca, Spain
| | - José L. Revuelta
- Instituto de Microbiología Bioquímica y Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, Campus Miguel de Unamuno, E-37007 Salamanca, Spain
| | - Alberto Jiménez
- Instituto de Microbiología Bioquímica y Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, Campus Miguel de Unamuno, E-37007 Salamanca, Spain
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89
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Schauer A, Knauer H, Ruckenstuhl C, Fussi H, Durchschlag M, Potocnik U, Fröhlich KU. Vacuolar functions determine the mode of cell death. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1793:540-5. [PMID: 19100296 DOI: 10.1016/j.bbamcr.2008.11.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 11/13/2008] [Accepted: 11/17/2008] [Indexed: 12/21/2022]
Abstract
The yeast vacuole plays a crucial role in cell homeostasis including pH regulation and degradation of proteins and organelles. Class C VPS genes code for proteins essential for vacuolar and endosomal vesicle fusion, their deletion results in the absence of a detectable vacuole. We found that single gene deletions of class C VPS genes result in a drastically enhanced sensitivity to treatment with acetic acid whereas sensitivity towards H2O2 remains largely unaffected. Interestingly acetic acid treatment known as an established inducer of yeast apoptosis leads to necrosis in class C VPS deletion strains. Their intracellular pH drops from 6.7 to 5.5 after acetic acid treatment, while in wild type the pH drops to just 6.3. When the intracellular pH in wild type is lowered below pH 5.5 using a higher concentration of acetic acid, the survival rate is similarly low as in the class C VPS mutants, however, the death phenotype is predominantly apoptotic. Hence, the vacuole not only prevents acetic acid induced cell death by buffering the cytosolic pH, but it also has a proapoptotic function.
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Affiliation(s)
- Alexandra Schauer
- Institute of Molecular Biosciences, University of Graz, Humboldtstrabetae 50, 8010 Graz, Austria
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90
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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: 1.5] [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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91
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Nedelcu AM. Comparative Genomics of Phylogenetically Diverse Unicellular Eukaryotes Provide New Insights into the Genetic Basis for the Evolution of the Programmed Cell Death Machinery. J Mol Evol 2009; 68:256-68. [DOI: 10.1007/s00239-009-9201-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 12/21/2008] [Accepted: 01/12/2009] [Indexed: 11/30/2022]
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92
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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: 3.8] [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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93
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Abstract
Accumulating evidence suggests that yeasts are capable of undergoing programmed cell death (PCD) to benefit long-term survival of the species, and that yeast and mammals may share at least partially conserved PCD pathways. In our experience, mammalian apoptosis assays have not been readily applicable to yeast. Therefore, to take advantage of yeast as a genetic tool to study PCD, we developed a yeast cell death assay that can reliably reveal viability differences between wild-type strains and strains lacking the mitochondrial fission genes DNM1/Drp1 and FIS1, orthologs of mammalian cell death regulators. Cell viability following treatment with acetic acid is quantified by colony formation and vital dye (FUN1) staining to reproducibly detect dose-dependent, genetically programmed yeast cell death.
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Affiliation(s)
- Xinchen Teng
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD, USA
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94
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Gan Y, Zhang L, Zhang Z, Dong S, Li J, Wang Y, Zheng X. The LCB2 subunit of the sphingolip biosynthesis enzyme serine palmitoyltransferase can function as an attenuator of the hypersensitive response and Bax-induced cell death. THE NEW PHYTOLOGIST 2009; 181:127-146. [PMID: 19076721 DOI: 10.1111/j.1469-8137.2008.02642.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Previous results showed that expression of the gene encoding the LONG-CHAIN BASE2 (LCB(2)) subunit of serine palmitoyltransferase (SPT), designated BcLCB(2), from nonheading Chinese cabbage (Brassica campestris ssp. chinensis) was up-regulated during hypersensitive cell death (HCD) induced by the Phytophthora boehmeriae elicitor PB90. Overexpression of BcLCB(2) in Nicotiana tabacum leaves suppressed the HCD normally initiated by elicitors and PB90-triggered H(2)O(2) accumulation. BcLCB(2) also functioned as a suppressor of mouse Bcl-2 associated X (Bax) protein-mediated HCD and cell death caused by Ralstonia solanacearum. BcLCB(2) overexpression suppressed Bax- and oxidant stress-triggered yeast cell death. Reactive oxygen species (ROS) accumulation induced by Bax was compromised in BcLCB(2)-overexpressing yeast cells. The findings that NbLCB(2) silencing in Nicotiana benthamiana enhanced elicitor-triggered HCD, combined with the fact that myriocin, a potent inhibitor of SPT, had no effect on Bax-induced programmed cell death, suggested that suppression of cell death was not involved in the dominant-negative effect that resulted from BcLCB(2) overexpression. A BcLCB(2) mutant assay showed that the suppression was not involved in SPT activity. The results suggest that plant HCD and stress-induced yeast cell death might share a common signal transduction pathway involving LCB(2), and that LCB(2) protects against cell death by inhibiting ROS accumulation, this inhibition being independent of SPT activity.
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Affiliation(s)
- Yunzhe Gan
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Lisha Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhengguang Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Suomeng Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Jun Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuanchao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaobo Zheng
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
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95
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Favre C, Aguilar PS, Carrillo MC. Oxidative stress and chronological aging in glycogen-phosphorylase-deleted yeast. Free Radic Biol Med 2008; 45:1446-56. [PMID: 18804161 DOI: 10.1016/j.freeradbiomed.2008.08.021] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 08/14/2008] [Accepted: 08/18/2008] [Indexed: 01/18/2023]
Abstract
Chronological aging in yeast resembles aging in mammalian, postmitotic tissues. Such chronological aging begins with entrance into the stationary phase after the nutrients are exhausted. Many changes in metabolism take place at this moment, and survival in this phase strongly depends on oxidative-stress resistance. In this study, hypo- and hyperglycogenic phenotypes of Saccharomyces cerevisiae strains with deletions of carbohydrate-metabolism enzymes were selected, and a comparison of their chronological longevities was made. Stress sensitivity, ROS, and apoptosis markers during aging were analyzed in the emerged candidates. Among the strains that accumulated greater amounts of glycogen, the deletion of glycogen phosphorylase, gph1delta, was unique in showing a shortened life span, stress intolerance, and higher levels of ROS during its survival. The transcription of superoxide dismutase genes during survival was three- to fourfold lower in gph1delta. Extra copies of SOD1/2 counteracted the stress sensitivity and the accelerated aging of gph1delta. In conclusion, the lack of gph1 produced a rapidly aging strain, which could be attributed, at least in part, to the weakened stress resistance associated with the decreased expression of both SODs. Gph1p seems to be a candidate in a scenario that could link early metabolic changes with other targets of the stress response during stationary-phase survival.
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Affiliation(s)
- Cristián Favre
- Institute of Experimental Physiology, CONICET, School of Biochemical Sciences, University of Rosario, Rosario, Argentina.
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96
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Padmanabhan N, Fichtner L, Dickmanns A, Ficner R, Schulz JB, Braus GH. The yeast HtrA orthologue Ynm3 is a protease with chaperone activity that aids survival under heat stress. Mol Biol Cell 2008; 20:68-77. [PMID: 18946088 DOI: 10.1091/mbc.e08-02-0178] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Ynm3 is the only budding yeast protein possessing a combination of serine protease and postsynaptic density 95/disc-large/zona occludens domains, a defining feature of the high temperature requirement A (HtrA) protein family. The bacterial HtrA/DegP is involved in protective stress response to aid survival at higher temperatures. The role of mammalian mitochondrial HtrA2/Omi in protein quality control is unclear, although loss of its protease activity results in susceptibility toward Parkinson's disease, in which mitochondrial dysfunction and impairment of protein folding and degradation are key pathogenetic features. We studied the role of the budding yeast HtrA, Ynm3, with respect to unfolding stresses. Similar to Escherichia coli DegP, we find that Ynm3 is a dual chaperone-protease. Its proteolytic activity is crucial for cell survival at higher temperature. Ynm3 also exhibits strong general chaperone activity, a novel finding for a eukaryotic HtrA member. We propose that the chaperone activity of Ynm3 may be important to improve the efficiency of proteolysis of aberrant proteins by averting the formation of nonproductive toxic aggregates and presenting them in a soluble state to its protease domain. Suppression studies with Deltaynm3 led to the discovery of chaperone activity in a nucleolar peptidyl-prolyl cis-trans isomerase, Fpr3, which could partly relieve the heat sensitivity of Deltaynm3.
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Affiliation(s)
- Nirmala Padmanabhan
- Abteilung Molekulare Mikrobiologie und Genetik, Institut für Mikrobiologie und Genetik, Georg August Universität Göttingen, Germany
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97
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Sapienza K, Bannister W, Balzan R. Mitochondrial involvement in aspirin-induced apoptosis in yeast. MICROBIOLOGY-SGM 2008; 154:2740-2747. [PMID: 18757807 DOI: 10.1099/mic.0.2008/017228-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We have previously reported that aspirin induces apoptosis in manganese superoxide dismutase (MnSOD)-deficient Saccharomyces cerevisiae cells when cultivated on the non-fermentable carbon source ethanol. Here, we investigated the role of mitochondria in aspirin-induced apoptosis. We report that aspirin had an inhibitory effect on cellular respiration, and caused the release of most of the mitochondrial cytochrome c and a dramatic drop in the mitochondrial membrane potential (DeltaPsi(m)). Also, aspirin reduced the intracellular cytosolic pH in the MnSOD-deficient cells growing in ethanol medium, but this did not seem to be the initial trigger that committed these cells to aspirin-induced apoptosis. Furthermore, loss of DeltaPsi(m) was not required for aspirin-induced release of cytochrome c, since the initial release of cytochrome c occurred prior to the disruption of the DeltaPsi(m). It is thus possible that cytochrome c release does not involve the early onset of the mitochondrial permeability transition, but only an alteration of the permeability of the outer mitochondrial membrane.
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Affiliation(s)
- Karen Sapienza
- Department of Physiology and Biochemistry, University of Malta, Msida MSD 2080, Malta
| | - William Bannister
- Department of Physiology and Biochemistry, University of Malta, Msida MSD 2080, Malta
| | - Rena Balzan
- Department of Physiology and Biochemistry, University of Malta, Msida MSD 2080, Malta
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98
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Rockenfeller P, Madeo F. Apoptotic death of ageing yeast. Exp Gerontol 2008; 43:876-81. [PMID: 18782613 PMCID: PMC5837017 DOI: 10.1016/j.exger.2008.08.044] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 08/01/2008] [Accepted: 08/04/2008] [Indexed: 12/30/2022]
Abstract
Yeast has been a valuable model to study replicative and chronological ageing processes. Replicative ageing is defined by the number of daughter cells a mother can give birth to and hence reflects the ageing situation in proliferating cells, whereas chronological ageing is widely accepted as a model for postmitotic tissue ageing. Since both ageing forms end in yeast programmed death (necrotic and apoptotic), and abrogation of cell death by deletion of the apoptotic machinery or diminishment of oxidative radicals leads to longevity, apoptosis and ageing seem closely connected. This review focuses on ageing as a physiological way to induce yeast apoptosis, which unexpectedly defines apoptosis as a pro- and not an anti-ageing mechanism.
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99
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Guan Y, Myers CL, Lu R, Lemischka IR, Bult CJ, Troyanskaya OG. A genomewide functional network for the laboratory mouse. PLoS Comput Biol 2008; 4:e1000165. [PMID: 18818725 PMCID: PMC2527685 DOI: 10.1371/journal.pcbi.1000165] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 07/21/2008] [Indexed: 11/19/2022] Open
Abstract
Establishing a functional network is invaluable to our understanding of gene function, pathways, and systems-level properties of an organism and can be a powerful resource in directing targeted experiments. In this study, we present a functional network for the laboratory mouse based on a Bayesian integration of diverse genetic and functional genomic data. The resulting network includes probabilistic functional linkages among 20,581 protein-coding genes. We show that this network can accurately predict novel functional assignments and network components and present experimental evidence for predictions related to Nanog homeobox (Nanog), a critical gene in mouse embryonic stem cell pluripotency. An analysis of the global topology of the mouse functional network reveals multiple biologically relevant systems-level features of the mouse proteome. Specifically, we identify the clustering coefficient as a critical characteristic of central modulators that affect diverse pathways as well as genes associated with different phenotype traits and diseases. In addition, a cross-species comparison of functional interactomes on a genomic scale revealed distinct functional characteristics of conserved neighborhoods as compared to subnetworks specific to higher organisms. Thus, our global functional network for the laboratory mouse provides the community with a key resource for discovering protein functions and novel pathway components as well as a tool for exploring systems-level topological and evolutionary features of cellular interactomes. To facilitate exploration of this network by the biomedical research community, we illustrate its application in function and disease gene discovery through an interactive, Web-based, publicly available interface at http://mouseNET.princeton.edu. Functionally related proteins interact in diverse ways to carry out biological processes, and each protein often participates in multiple pathways. Proteins are therefore organized into a complex network through which different functions of the cell are carried out. An accurate description of such a network is invaluable to our understanding of both the system-level features of a cell and those of an individual biological process. In this study, we used a probabilistic model to combine information from diverse genome-scale studies as well as individual investigations to generate a global functional network for mouse. Our analysis of the global topology of this network reveals biologically relevant systems-level characteristics of the mouse proteome, including conservation of functional neighborhoods and network features characteristic of known disease genes and key transcriptional regulators. We have made this network publicly available for search and dynamic exploration by researchers in the community. Our Web interface enables users to easily generate hypotheses regarding potential functional roles of uncharacterized proteins, investigate possible links between their proteins of interest and disease, and identify new players in specific biological processes.
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Affiliation(s)
- Yuanfang Guan
- Lewis-Sigler Institute for Integrative Genomics, Carl Icahn Laboratory, Princeton University, Princeton, New Jersey, United States of America
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Chad L. Myers
- Department of Computer Science, Princeton University, Princeton, New Jersey, United States of America
| | - Rong Lu
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Ihor R. Lemischka
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Carol J. Bult
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Olga G. Troyanskaya
- Lewis-Sigler Institute for Integrative Genomics, Carl Icahn Laboratory, Princeton University, Princeton, New Jersey, United States of America
- Department of Computer Science, Princeton University, Princeton, New Jersey, United States of America
- * E-mail:
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100
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Nonapoptotic death of Saccharomyces cerevisiae cells that is stimulated by Hsp90 and inhibited by calcineurin and Cmk2 in response to endoplasmic reticulum stresses. EUKARYOTIC CELL 2008; 7:2037-51. [PMID: 18806210 DOI: 10.1128/ec.00291-08] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Endoplasmic reticulum (ER) stress can trigger apoptosis and necrosis in many types of mammalian cells. Previous studies in yeast found little or no cell death in response to the ER stressor tunicamycin, but a recent study suggested widespread apoptosis-like death. Here we show that wild-type laboratory Saccharomyces cerevisiae cells responding to tunicamycin die by nonapoptotic mechanisms in low-osmolyte culture media and survive for long periods of time in standard synthetic media. Survival requires calcineurin, a Ca(2+)/calmodulin-dependent protein phosphatase, but none of its known targets. The Ca(2+)/calmodulin-dependent protein kinase Cmk2 was identified as an indirect target of calcineurin that suppresses death of calcineurin-deficient cells. Death of Cmk2- and/or calcineurin-deficient S. cerevisiae cells was preceded by accumulation of reactive oxygen species but was not associated with hallmarks of apoptosis and was not dependent on Mca1, Aif1, Nuc1, or other factors implicated in apoptosis-like death. Cmk2 and calcineurin also independently suppressed the death of S. cerevisiae cells responding to dithiothreitol or miconazole, a common azole-class antifungal drug. Though inhibitors of Hsp90 have been shown to diminish calcineurin signaling in S. cerevisiae and to synergistically inhibit growth in combination with azoles, they did not stimulate death of S. cerevisiae cells in combination with miconazole or tunicamycin, and instead they prevented the death of calcineurin- and Cmk2-deficient cells. These findings reveal a novel prodeath role for Hsp90 and antideath roles for calcineurin and Cmk2 that extend the life span of S. cerevisiae cells responding to both natural and clinical antifungal compounds.
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