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Abstract
GRASP65 (Golgi reassembly and stacking protein of 65 KDa) is a cis-Golgi protein with roles in Golgi structure, membrane trafficking and cell signalling. It is cleaved by caspase-3 early in apoptosis, promoting Golgi fragmentation. We now show that cleavage is needed for Fas-mediated apoptosis: expression of caspase-resistant GRASP65 protects cells, whereas expression of membrane proximal caspase-cleaved GRASP65 fragments dramatically sensitises cells. GRASP65 coordinates passage through the Golgi apparatus of proteins containing C-terminal hydrophobic motifs, via its tandem PDZ type ‘GRASP' domains. Fas/CD95 contains a C-terminal leucine–valine pairing so its trafficking might be coordinated by GRASP65. Mutagenesis of the Fas/CD95 LV motif reduces the number of cells with Golgi-associated Fas/CD95, and generates a receptor that is more effective at inducing apoptosis; however, siRNA-mediated silencing or expression of mutant GRASP65 constructs do not alter the steady state distribution of Fas/CD95. We also find no evidence for a GRASP65–Fas/CD95 interaction at the molecular level. Instead, we find that the C-terminal fragments of GRASP65 produced following caspase cleavage are targeted to mitochondria, and ectopic expression of these sensitises HeLa cells to Fas ligand. Our data suggest that GRASP65 cleavage promotes Fas/CD95-mediated apoptosis via release of C-terminal fragments that act at the mitochondria, and we identify Bcl-XL as a candidate apoptotic binding partner for GRASP65.
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102
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Cacas JL. Devil inside: does plant programmed cell death involve the endomembrane system? PLANT, CELL & ENVIRONMENT 2010; 33:1453-1473. [PMID: 20082668 DOI: 10.1111/j.1365-3040.2010.02117.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Eukaryotic cells have to constantly cope with environmental cues and integrate developmental signals. Cell survival or death is the only possible outcome. In the field of animal biology, tremendous efforts have been put into the understanding of mechanisms underlying cell fate decision. Distinct organelles have been proven to sense a broad range of stimuli and, if necessary, engage cell death signalling pathway(s). Over the years, forward and reverse genetic screens have uncovered numerous regulators of programmed cell death (PCD) in plants. However, to date, molecular networks are far from being deciphered and, apart from the autophagic compartment, no organelles have been assigned a clear role in the regulation of cellular suicide. The endomembrane system (ES) seems, nevertheless, to harbour a significant number of cell death mediators. In this review, the involvement of this system in the control of plant PCD is discussed in-depth, as well as compared and contrasted with what is known in animal and yeast systems.
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Affiliation(s)
- Jean-Luc Cacas
- Institut de Recherche pour le Développement, Equipe 2, Mécanismes des Résistances, Montpellier Cedex 5, France.
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103
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Krumschnabel G, Ebner HL, Hess MW, Villunger A. Apoptosis and necroptosis are induced in rainbow trout cell lines exposed to cadmium. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 99:73-85. [PMID: 20435356 DOI: 10.1016/j.aquatox.2010.04.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 03/30/2010] [Accepted: 04/02/2010] [Indexed: 05/29/2023]
Abstract
Cadmium is an important environmental toxicant that can kill cells. A number of studies have implicated apoptosis as well as necrosis and, most recently, a form of programmed necrosis termed necroptosis in the process of cadmium-mediated toxicity, but the exact mechanism remains ill-defined and may depend on the affected cell type. This study investigated which mode of cell death may be responsible for cell death induction in cadmium-exposed trout cell lines from gill and liver and if this cell death was sensitive to inhibitors of necroptosis or apoptosis, respectively. It was observed that intermediate levels of cadmium that killed approximately 50% of the cells over 96-120h of exposure caused cell death that morphologically resembled apoptosis and was associated with an increase of apoptotic markers such as the number of cells with diminished DNA content (sub-G1 cells), condensed or fragmented nuclei, and elevation of caspase-3 activity. At the same time, however, cells also lost plasma membrane integrity, as indicated by uptake of propidium iodide, showed a decrease of ATP levels and mitochondrial membrane potential, and displayed cell swelling, signs associated with secondary necrosis, or equally possible, necroptotic cell death. Importantly, many of these alterations were at least partly inhibited by the necroptosis inhibitor necrostatin-1 and were to a lesser extent also sensitive to the pan-caspase inhibitor zVAD-fmk, indicating that multiple modes of cell death are concurrently induced in cadmium-exposed trout cells, including necroptosis and apoptosis. Cell death appeared to lack concurrent radical formation, consistent with genetically regulated necroptotic cell death, but was characterized by the rapid induction of DNA damage markers, and the early onset of disintegration of the Golgi complex. Comparative experiments evaluating copper-toxicity indicated that in comparison to cadmium much higher concentrations of this metal were required to induce cell death and that neither necrostatin-1 nor a pan-caspase inhibitor conferred protection, suggesting that additional modes of cell death can be triggered in response to poisoning with heavy metals.
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Affiliation(s)
- Gerhard Krumschnabel
- Division of Developmental Immunology, Biocenter, Medical University Innsbruck, Fritz-Preglstr. 3, Innsbruck, Austria.
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104
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Lavoie JN, Landry MC, Faure RL, Champagne C. Src-family kinase signaling, actin-mediated membrane trafficking and organellar dynamics in the control of cell fate: lessons to be learned from the adenovirus E4orf4 death factor. Cell Signal 2010; 22:1604-14. [PMID: 20417707 DOI: 10.1016/j.cellsig.2010.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 04/15/2010] [Indexed: 12/15/2022]
Abstract
Evidence has accumulated that there are different modes of regulated cell death, which share overlapping signaling pathways. Cytoskeletal-dependent inter-organellar communication as a result of protein and lipid trafficking in and out of organelles has emerged as a common, key issue in the regulation of cell death modalities. The movement of proteins and lipids between cell compartments is believed to relay death signals in part through modifications of organelles dynamics. Little is known, however, regarding how trafficking is integrated within stress signaling pathways directing organelle-specific remodeling events. In this review, we discuss emerging evidence supporting a role for regulated changes in actin dynamics and intracellular membrane flow. Based on recent findings using the adenovirus E4orf4 death factor as a probing tool to tackle the mechanistic underpinnings that control alternative modes of cell death, we propose the existence of multifunctional platforms at the endosome-Golgi interface regulated by SFK-signaling. These endosomal platforms could be mobilized during cell activation processes to reorganize cellular membranes and promote inter-organelle signaling.
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Affiliation(s)
- Josée N Lavoie
- Centre de Recherche en Cancérologie de l'Université Laval, L'Hôtel-Dieu de Québec, CRCHUQ, Québec, Canada.
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105
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Wlodkowic D, Skommer J, McGuinness D, Hillier C, Darzynkiewicz Z. ER-Golgi network--a future target for anti-cancer therapy. Leuk Res 2009; 33:1440-7. [PMID: 19595459 DOI: 10.1016/j.leukres.2009.05.025] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 05/14/2009] [Accepted: 05/29/2009] [Indexed: 02/04/2023]
Abstract
Tumor cell demise is an important event in the elimination of abnormal malignant cells and provides an important mechanism of natural tumor suppression. Abnormalities incapacitating these finely tuned processes provide a strong advantage for cancer clones to succeed in evading both the physiological control systems and therapeutic intervention. Expanding our knowledge of the molecular "crosstalks" that regulate tumor cell demise is crucial in guiding the successful design of future anti-cancer therapeutics. Although currently available data indicate that elimination of malignant cells often depends on classical apoptotic pathways (mitochondrial and/or death-receptor pathways), the evidence is mounting that alternative apoptotic and non-apoptotic pathways may effectively contribute to tumor cell death. The assumption that every organelle is capable of sensing, amplificating and executing cell death is also a relatively novel and unexplored concept. As recently shown, the secretory pathway can be actively involved in sensing stress stimuli and possibly even initiating and propagating cell death signaling. Experimental evidence indicates that ER and Golgi apparatus can activate both pro-survival (recovery) mechanisms as well as cell suicide programs if the stress-signaling threshold is exceeded. It is thus conceivable that the fragile balance of protein trafficking between various subcellular compartments provides an exceptional therapeutic opportunity. Interestingly, a growing number of reports recognize novel therapeutic targets, including proteins in control of endoplasmic reticulum (ER) and Golgi homeostasis. Further studies are, however, needed to elucidate precise signaling pathways emanating from ER-Golgi compartment. Development of more potent and selective small-molecule drugs that activate ER-Golgi mediated cell demise is also needed. As the interest in the role of ER-Golgi network during cancer cell death has been gaining momentum, we attempt here to critically appraise current status of development of investigational anti-cancer agents that target ER and/or Golgi.
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Affiliation(s)
- Donald Wlodkowic
- Department of Biological & Biomedical Sciences, Glasgow Caledonian University, Glasgow, UK.
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106
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Morphological and ultrastructural effects of microcystin-LR from Microcystis aeruginosa extract on a kidney cell line. Toxicon 2009; 54:283-94. [DOI: 10.1016/j.toxicon.2009.04.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 04/13/2009] [Accepted: 04/14/2009] [Indexed: 11/21/2022]
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107
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Battista MC, Roberge C, Martinez A, Gallo-Payet N. 24-dehydrocholesterol reductase/seladin-1: a key protein differentially involved in adrenocorticotropin effects observed in human and rat adrenal cortex. Endocrinology 2009; 150:4180-90. [PMID: 19520779 DOI: 10.1210/en.2009-0410] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
DHCR24 (24-dehydrocholesterol reductase), or seladin-1, is one of the most expressed genes in the adrenal gland. Because the rat and human adult adrenal cortex differ in their respective functional properties, the aim of the present study was to verify whether seladin-1 may be differentially involved in basal and ACTH-stimulated steroidogenesis and oxidative stress management. Seladin-1 expression was predominantly observed in both human and rat zona fasciculata, with a predominant cytoplasmic localization in human cells and a nucleo-cytoplasmic distribution in rat cells. In human fasciculata cells, localization of the protein was primarily associated with the endoplasmic reticulum. Although its expression was increased by ACTH, its intracellular localization was not altered by ACTH treatment (10 nm) or by the seladin-1 inhibitor U18666A (75 nm). Preincubation with U18666A did not modify the ACTH-induced increase in cortisol secretion but abolished the ACTH-induced increase in dehydroepiandrosterone secretion. In rat fasciculata cells, ACTH induced a massive redistribution of seladin-1 from the cytoplasm (cis-Golgi apparatus) to the nucleus, which was inhibited by preincubation with U18666A. Preincubation with U18666A also decreased ACTH-induced seladin-1 and 11beta-hydroxylase protein expression as well as corticosterone production, increased ACTH-induced ROS production but decreased ACTH-induced expression of the detoxifying protein aldo-ketoreductase 1b7. Thus, protection against acutely elevated ACTH-induced oxidative stress in rat fasciculata cells is correlated with nuclear relocalization of seladin-1 and its effects on cellular detoxifying machinery. Altogether, these results indicate that seladin-1 expression and intracellular localization are correlated with both the intensity and nature of ACTH-induced steroidogenesis and resultant oxidative stress.
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Affiliation(s)
- Marie-Claude Battista
- Service d'Endocrinologie, Department of Medicine, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec, Canada
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108
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Landry MC, Sicotte A, Champagne C, Lavoie JN. Regulation of cell death by recycling endosomes and golgi membrane dynamics via a pathway involving Src-family kinases, Cdc42 and Rab11a. Mol Biol Cell 2009; 20:4091-106. [PMID: 19641023 DOI: 10.1091/mbc.e09-01-0057] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Actin dynamics and membrane trafficking influence cell commitment to programmed cell death through largely undefined mechanisms. To investigate how actin and recycling endosome (RE) trafficking can engage death signaling, we studied the death program induced by the adenovirus early region 4 open reading frame 4 (E4orf4) protein as a model. We found that in the early stages of E4orf4 expression, Src-family kinases (SFKs), Cdc42, and actin perturbed the organization of the endocytic recycling compartment and promoted the transport of REs to the Golgi apparatus, while inhibiting recycling of protein cargos to the plasma membrane. The resulting changes in Golgi membrane dynamics that relied on actin-regulated Rab11a membrane trafficking triggered scattering of Golgi membranes and contributed to the progression of cell death. A similar mobilization of RE traffic mediated by SFKs, Cdc42 and Rab11a also contributed to Golgi fragmentation and to cell death progression in response to staurosporine, in a caspase-independent manner. Collectively, these novel findings suggest that diversion of RE trafficking to the Golgi complex through a pathway involving SFKs, Cdc42, and Rab11a plays a general role in death signaling by mediating regulated changes in Golgi dynamics.
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Affiliation(s)
- Marie-Claude Landry
- Centre de Recherche en Cancérologie de l'Université Laval, L'Hôtel-Dieu de Québec, Centre de Recherche du Centre Hospitalier Universitaire de Quebec, Québec G1R 2J6, Canada
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109
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Abstract
Apoptosis proceeds through a set of evolutionarily conserved processes that co-ordinate the elimination of damaged or unneeded cells. This program of cell death is carried out by organelle-directed regulators, including the Bcl-2 proteins, and ultimately executed by proteases of the caspase family. Although the biochemical mechanisms of apoptosis are increasingly understood, the underlying cell biology orchestrating programmed cell death remains enigmatic. In this review, we summarize the current understanding of Bcl-2 protein regulation and caspase activation while examining cell biological mechanisms and consequences of apoptotic induction. Organellar contributions to apoptotic induction include death receptor endocytosis, mitochondrial and lysosomal permeabilization, endoplasmic reticulum calcium release and fragmentation of the Golgi apparatus. These early apoptotic events are accompanied by stabilization of the microtubule cytoskeleton and translocation of organelles to the microtubule organizing center. Together, these phenomena establish a model of apoptotic induction whereby a cytoskeletal-dependent coalescence and 'scrambling' of organelles in the paranuclear region co-ordinates apoptotic communication, caspase activation and cell death.
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Affiliation(s)
- Joseph E Aslan
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
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110
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Characterization of a novel Golgi apparatus-localized latency determinant encoded by human cytomegalovirus. J Virol 2009; 83:5615-29. [PMID: 19297488 DOI: 10.1128/jvi.01989-08] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human cytomegalovirus (HCMV) exists indefinitely in infected individuals by a yet poorly characterized latent infection in hematopoietic cells. We previously demonstrated a requirement for the putative UL138 open reading frame (ORF) in promoting a latent infection in CD34(+) hematopoietic progenitor cells (HPCs) infected in vitro. In our present study, we have identified two coterminal transcripts of 2.7 and 3.6 kb and a 21-kilodalton (kDa) protein (pUL138) that are derived from the UL138 locus with early-late gene kinetics during productive infection. The UL138 transcripts and protein are detected in both fibroblasts and HPCs. A recombinant virus, FIX-UL138(STOP), that synthesizes the UL138 transcripts but not the protein exhibited a partial loss-of-latency phenotype in HPCs, similar to the phenotype observed for the UL138-null recombinant virus. This finding suggests that the UL138 protein is required for latency, but it does not exclude the possibility that the UL138 transcripts or other ORFs also contribute to latency. The mechanisms by which pUL138 contributes to latency remain unknown. While the 86- and 72-kDa immediate-early proteins were not detected in HPCs infected with HCMV in vitro, pUL138 did not function directly to suppress expression from the major immediate-early promoter in reporter assays. Interestingly, pUL138 localizes to the Golgi apparatus in infected cells but is not incorporated into virus particles. The localization of pUL138 to the Golgi apparatus suggests that pUL138 contributes to HCMV latency by a novel mechanism. pUL138 is the first HCMV protein demonstrated to promote an infection with the hallmarks of latency in CD34(+) HPCs.
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111
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Pavlíková M, Tatarková Z, Sivonová M, Kaplan P, Krizanová O, Lehotský J. Alterations induced by ischemic preconditioning on secretory pathways Ca2+-ATPase (SPCA) gene expression and oxidative damage after global cerebral ischemia/reperfusion in rats. Cell Mol Neurobiol 2009; 29:909-16. [PMID: 19288187 DOI: 10.1007/s10571-009-9374-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 02/19/2009] [Indexed: 11/30/2022]
Abstract
Ischemic preconditioning (IPC) represents the phenomenon of CNC adaptation, which results in increased tolerance of CNS to lethal ischemia. Brain ischemia/reperfusion (IRI) initiates a catastrophic cascade in which many subcellular organelles play an important role. The Golgi apparatus, which is a part of secretory pathways (SP), represents the Ca(2+) store and regulates secretion of proteins for growth/reorganization of neuronal circuit by secretory Ca(2+)ATPases (SPCA1). The purpose of this study is to evaluate the effect of IRI and preconditioning on SPCA1 gene expression and oxidative damage after 4-vessel occlusion for 15 min and after being exposed to different reperfusion periods. Rats were preconditioned by 5 min of sub-lethal ischemia and 2 days later, 15 min of lethal ischemia was induced. Our experiments conclusively showed IRI-induced depression of SPCA activity and lipo- and protein oxidation in rat hippocampal membranes. IRI also activates the induction of SPCA1 gene expression in later reperfusion periods. IPC partially suppresses lipo- and protein oxidation in hippocampal membranes and leads to partiall rovery of the ischemic-induced depression of SPCA activity. In addition, IPC initiates earlier cellular response to the injury by the significant elevation of mRNA expression to 142% comparing to 1 h of corresponding reperfusion and to 11% comparing to 24 h of corresponding reperfusion, respectively. Similar patterns were observed on the translational level by Western blot analysis. Our results indicate the specific SPCA1 expression pattern in ischemic hippocampus. It also shows that the SPCA expression and the post-translational changes induced by ischemia are modulated by the IPC. This might serve to understand the molecular mechanisms involved in the structural integrity and function of the SP after ischemic challenge. It also suggests that there is a correlation of SPCA function with the role of SP in the response to pre-ischemic challenge.
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Affiliation(s)
- M Pavlíková
- Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University, 036 01 Martin, Slovak Republic
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112
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Expression of the novel Golgi protein GoPro49 is developmentally regulated during mesenchymal differentiation. Dev Dyn 2008; 237:2243-55. [DOI: 10.1002/dvdy.21646] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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113
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Lukas TJ, Miao H, Chen L, Riordan SM, Li W, Crabb AM, Wise A, Du P, Lin SM, Hernandez MR. Susceptibility to glaucoma: differential comparison of the astrocyte transcriptome from glaucomatous African American and Caucasian American donors. Genome Biol 2008; 9:R111. [PMID: 18613964 PMCID: PMC2530868 DOI: 10.1186/gb-2008-9-7-r111] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 06/18/2008] [Accepted: 07/09/2008] [Indexed: 12/23/2022] Open
Abstract
Comparison of gene expression in normal and glaucomatous eyes from Caucasian American and African American donors reveals differences that might reflect different susceptibility to glaucoma. Background Epidemiological and genetic studies indicate that ethnic/genetic background plays an important role in susceptibility to primary open angle glaucoma (POAG). POAG is more prevalent among the African-descent population compared to the Caucasian population. Damage in POAG occurs at the level of the optic nerve head (ONH) and is mediated by astrocytes. Here we investigated differences in gene expression in primary cultures of ONH astrocytes obtained from age-matched normal and glaucomatous donors of Caucasian American (CA) and African American (AA) populations using oligonucleotide microarrays. Results Gene expression data were obtained from cultured astrocytes representing 12 normal CA and 12 normal AA eyes, 6 AA eyes with POAG and 8 CA eyes with POAG. Data were normalized and significant differential gene expression levels detected by using empirical Bayesian shrinkage moderated t-statistics. Gene Ontology analysis and networks of interacting proteins were constructed using the BioGRID database. Network maps included regulation of myosin, actin, and protein trafficking. Real-time RT-PCR, western blots, ELISA, and functional assays validated genes in the networks. Conclusion Cultured AA and CA glaucomatous astrocytes retain differential expression of genes that promote cell motility and migration, regulate cell adhesion, and are associated with structural tissue changes that collectively contribute to neural degeneration. Key upregulated genes include those encoding myosin light chain kinase (MYLK), transforming growth factor-β receptor 2 (TGFBR2), rho-family GTPase-2 (RAC2), and versican (VCAN). These genes along with other differentially expressed components of integrated networks may reflect functional susceptibility to chronic elevated intraocular pressure that is enhanced in the optic nerve head of African Americans.
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Affiliation(s)
- Thomas J Lukas
- Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University, E Chicago Ave, Chicago, IL 60611, USA.
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114
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Renal cell apoptosis induced by nephrotoxic drugs: cellular and molecular mechanisms and potential approaches to modulation. Apoptosis 2008; 13:11-32. [PMID: 17968659 DOI: 10.1007/s10495-007-0151-z] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Apoptosis plays a central role not only in the physiological processes of kidney growth and remodeling, but also in various human renal diseases and drug-induced nephrotoxicity. We present in a synthetic fashion the main molecular and cellular pathways leading to drug-induced apoptosis in kidney and the mechanisms regulating it. We illustrate them using three main nephrotoxic drugs (cisplatin, gentamicin, and cyclosporine A). We discuss the main regulators and effectors that have emerged as key targets for the design of therapeutic strategies. Novel approaches using gene therapy, antisense strategies, recombinant proteins, or compounds obtained from both classical organic and combinatorial chemistry are examined. Finally, key issues that need to be addressed for the success of apoptosis-based therapies are underlined.
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115
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Kang HG, Kuhl JC, Kachroo P, Klessig DF. CRT1, an Arabidopsis ATPase that interacts with diverse resistance proteins and modulates disease resistance to turnip crinkle virus. Cell Host Microbe 2008; 3:48-57. [PMID: 18191794 DOI: 10.1016/j.chom.2007.11.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 09/12/2007] [Accepted: 11/26/2007] [Indexed: 01/30/2023]
Abstract
Plant immunity frequently involves the recognition of pathogen-encoded avirulence (avr) factors by their corresponding plant resistance (R) proteins. This triggers the hypersensitive response (HR) where necrotic lesions formed at the site(s) of infection help restrict pathogen spread. HRT is an Arabidopsis R protein required for resistance to turnip crinkle virus (TCV). In a genetic screen for mutants compromised in the recognition of TCV's avr factor, we identified crt1 (compromised recognition of TCV), a mutant that prematurely terminates an ATPase protein. Following TCV infection, crt1 developed a spreading HR and failed to control viral replication and spread. crt1 also suppressed HR-like cell death induced by ssi4, a constitutively active R protein, and by Pseudomonas syringae carrying avrRpt2. Furthermore, CRT1 interacts with HRT, SSI4, and two other R proteins, RPS2 and Rx. These data identify CRT1 as an important mediator of defense signaling triggered by distinct classes of R proteins.
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Affiliation(s)
- Hong-Gu Kang
- Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA
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116
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Abstract
In many cell types, intracellular organelles are involved along the progression of cell death. While many studies have focused on individual organelles such as mitochondria, evidence has accumulated that different organelles are simultaneously engaged in dynamic changes induced by death signaling before nuclear alterations are evident. This chapter examines approaches to evaluate dynamic aspects of organelle changes and intermixing during apoptosis. The methods presented here, which have been adapted from approaches used in the field of membrane traffic, enable the evaluation of mitochondrial intermixing with other organelles and the centrifugal movements of internal membranes that are associated, in particular, with death receptor-mediated apoptosis.
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117
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Establishment of a cell model of ALS disease: Golgi apparatus disruption occurs independently from apoptosis. Biotechnol Lett 2007; 30:603-10. [PMID: 18004513 DOI: 10.1007/s10529-007-9595-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 10/24/2007] [Accepted: 10/30/2007] [Indexed: 10/22/2022]
Abstract
The Golgi apparatus (GA) appears disrupted in motor neurons of amyotrophic lateral sclerosis (ALS). Here, mouse motor neuron-like NSC-34 cell lines stably expressing human superoxide dismutase 1 (hSOD1)(wt) and mutant hSOD1(G93A), as an ALS cell model, were constructed. The number of cells with disrupted GA increased from 14% to 34%. Furthermore, NSC-34/hSOD1(G93A) cells showed lower levels of proliferation and differentiation. GA disruption was not caused by apoptosis as determined by several techniques including caspase-3 activation. Similarly, spinal cords from ALS patients did not show caspase-3 activation. Therefore, NSC-34/hSOD1(G93A) cells are a suitable cell model to study GA dysfunction in ALS.
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118
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Nachmias B, Lazar I, Elmalech M, Abed-El-Rahaman I, Asshab Y, Mandelboim O, Perlman R, Ben-Yehuda D. Subcellular localization determines the delicate balance between the anti- and pro-apoptotic activity of Livin. Apoptosis 2007; 12:1129-42. [PMID: 17294084 DOI: 10.1007/s10495-006-0049-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Livin is a member of the Inhibitor of Apoptosis Protein family which inhibits apoptosis induced by a variety of stimuli. We previously identified Livin and demonstrated that following apoptotic stimuli, Livin is cleaved by effector caspases to produce a truncated form with paradoxical pro-apoptotic activity. In the present study, we reveal that while full-length Livin shows diffuse cytoplasmic localization, truncated Livin (tLivin) is found in a peri-nuclear distribution with marked localization to the Golgi apparatus. Using mutation analysis, we identified two domains that are crucial for the pro-apoptotic activity of tLivin: the N-terminal region of tLivin which is exposed by cleavage, and the RING domain. We demonstrate that, of the N-terminal sequence, only the first N-terminal glycine residue dictates the peri-nuclear distribution of tLivin. However, while the perinuclear localization of tLivin is essential, it is not sufficient for tLivin to exert its pro-apoptotic function. Once tLivin is properly localized, an intact RING domain enables its pro-apoptotic function.
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Affiliation(s)
- Boaz Nachmias
- Department of Hematology, Hadassah - Hebrew University Medical Center, P.O.B. 12000, Jerusalem, 91120, Israel
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119
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Mukherjee S, Chiu R, Leung SM, Shields D. Fragmentation of the Golgi apparatus: an early apoptotic event independent of the cytoskeleton. Traffic 2007; 8:369-78. [PMID: 17394485 DOI: 10.1111/j.1600-0854.2007.00542.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Golgi apparatus undergoes irreversible fragmentation during apoptosis, in part as a result of caspase-mediated cleavage of several Golgi-associated proteins. However, Golgi structure and orientation is also regulated by the cytoskeleton and cytoskeletal changes have been implicated in inducing apoptosis. Consequently, we have analyzed the role of actin filaments and microtubules in apoptotic Golgi fragmentation. We demonstrate that in Fas receptor-activated cells, fragmentation of the Golgi apparatus was an early event that coincided with release of cytochrome c from mitochondria. Significantly, Golgi fragmentation preceded major changes in the organization of both the actin cytoskeleton and microtubules. In staurosporine-treated cells, actin filament organization was rapidly disrupted; however, the Golgi apparatus maintained its juxtanuclear localization and underwent complete fragmentation only at later times. Attempts to stabilize actin filaments with jasplakinolide prior to treatment with staurosporine did not prevent Golgi fragmentation. Finally, in response to Fas receptor activation or staurosporine treatment the levels of beta-actin or alpha-tubulin remained unaltered, whereas several Golgi proteins, p115 and golgin-160, underwent caspase-mediated cleavage. Our data demonstrate that breakdown of the Golgi apparatus is an early event during apoptosis that occurs independently of major changes to the actin and tubulin cytoskeleton.
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Affiliation(s)
- Shaeri Mukherjee
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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120
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Nakagomi S, Barsoum MJ, Bossy-Wetzel E, Sütterlin C, Malhotra V, Lipton SA. A Golgi fragmentation pathway in neurodegeneration. Neurobiol Dis 2007; 29:221-31. [PMID: 17964175 DOI: 10.1016/j.nbd.2007.08.015] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 08/10/2007] [Accepted: 08/22/2007] [Indexed: 11/16/2022] Open
Abstract
The Golgi apparatus processes intracellular proteins, but undergoes disassembly and fragmentation during apoptosis in several neurodegenerative disorders such as amyotrophic lateral sclerosis and Alzheimer's disease. It is well known that other cytoplasmic organelles play important roles in cell death pathways. Thus, we hypothesized that Golgi fragmentation might participate in transduction of cell death signals. Here, we found that Golgi fragmentation and dispersal precede neuronal cell death triggered by excitotoxins, oxidative/nitrosative insults, or ER stress. Pharmacological intervention or overexpression of the C-terminal fragment of Grasp65, a Golgi-associated protein, inhibits fragmentation and decreases or delays neuronal cell death. Inhibition of mitochondrial or ER cell death pathways also decreases Golgi fragmentation, indicating crosstalk between organelles and suggesting that the Golgi may be a common downstream-effector of cell death. Taken together, these findings implicate the Golgi as a sensor of stress signals in cell death pathways.
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Affiliation(s)
- Saya Nakagomi
- Center for Neuroscience, Aging, and Stem Cell Research, Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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121
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Severe acute respiratory syndrome coronavirus gene 7 products contribute to virus-induced apoptosis. J Virol 2007. [PMID: 17686858 DOI: 10.1128/jvi.01266‐07] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The proteins encoded by gene 7 of the severe acute respiratory syndrome coronavirus (SARS-CoV) have been demonstrated to have proapoptotic activity when expressed from cDNA but appear to be dispensable for virus replication. Recombinant SARS-CoVs bearing deletions in gene 7 were used to assess the contribution of gene 7 to virus replication and apoptosis in several transformed cell lines, as well as to replication and pathogenesis in golden Syrian hamsters. Deletion of gene 7 had no effect on SARS-CoV replication in transformed cell lines, nor did it alter the induction of early apoptosis markers such as annexin V binding and activation of caspase 3. However, viruses with gene 7 disruptions were not as efficient as wild-type virus in inducing DNA fragmentation, as judged by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) staining, indicating that the gene 7 products do contribute to virus-induced apoptosis. Disruption of gene 7 did not affect virus replication or morbidity in golden Syrian hamsters, suggesting that the gene 7 products are not required for acute infection in vivo. The data indicate that open reading frames 7a and 7b contribute to but are not solely responsible for the apoptosis seen in SARS-CoV-infected cells.
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122
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Tarragó-Trani MT, Storrie B. Alternate routes for drug delivery to the cell interior: pathways to the Golgi apparatus and endoplasmic reticulum. Adv Drug Deliv Rev 2007; 59:782-97. [PMID: 17669543 PMCID: PMC2134838 DOI: 10.1016/j.addr.2007.06.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Accepted: 06/12/2007] [Indexed: 11/29/2022]
Abstract
The targeted delivery of drugs to the cell interior can be accomplished by taking advantage of the various receptor-mediated endocytic pathways operating in a particular cell. Among these pathways, the retrograde trafficking pathway from endosomes to the Golgi apparatus, and endoplasmic reticulum is of special importance since it provides a route to deliver drugs bypassing the acid pH, hydrolytic environment of the lysosome. The existence of pathways for drug or antigen delivery to the endoplasmic reticulum and Golgi apparatus has been to a large extent an outcome of research on the trafficking of A/B type-bacterial or plant toxins such as Shiga toxin within the cell. The targeting properties of these toxins reside in their B subunit. In this article we present an overview of the multiplicity of pathways to deliver drugs intracellularly. We highlight the retrograde trafficking pathway illustrated by Shiga toxin and Shiga-like toxin, and the potential role of the B subunit of these toxins as carriers of drugs, antigens and imaging agents.
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Affiliation(s)
- Maria Teresa Tarragó-Trani
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
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123
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Schaecher SR, Touchette E, Schriewer J, Buller RM, Pekosz A. Severe acute respiratory syndrome coronavirus gene 7 products contribute to virus-induced apoptosis. J Virol 2007; 81:11054-68. [PMID: 17686858 PMCID: PMC2045523 DOI: 10.1128/jvi.01266-07] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The proteins encoded by gene 7 of the severe acute respiratory syndrome coronavirus (SARS-CoV) have been demonstrated to have proapoptotic activity when expressed from cDNA but appear to be dispensable for virus replication. Recombinant SARS-CoVs bearing deletions in gene 7 were used to assess the contribution of gene 7 to virus replication and apoptosis in several transformed cell lines, as well as to replication and pathogenesis in golden Syrian hamsters. Deletion of gene 7 had no effect on SARS-CoV replication in transformed cell lines, nor did it alter the induction of early apoptosis markers such as annexin V binding and activation of caspase 3. However, viruses with gene 7 disruptions were not as efficient as wild-type virus in inducing DNA fragmentation, as judged by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) staining, indicating that the gene 7 products do contribute to virus-induced apoptosis. Disruption of gene 7 did not affect virus replication or morbidity in golden Syrian hamsters, suggesting that the gene 7 products are not required for acute infection in vivo. The data indicate that open reading frames 7a and 7b contribute to but are not solely responsible for the apoptosis seen in SARS-CoV-infected cells.
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Affiliation(s)
- Scott R Schaecher
- Department of Molecular Microbiology, Washington University in St. Louis School of Medicine, 660 S. Euclid Ave., Campus Box 8230, St. Louis, Missouri 63110, USA
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124
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Okunade GW, Miller ML, Azhar M, Andringa A, Sanford LP, Doetschman T, Prasad V, Shull GE. Loss of the Atp2c1 secretory pathway Ca(2+)-ATPase (SPCA1) in mice causes Golgi stress, apoptosis, and midgestational death in homozygous embryos and squamous cell tumors in adult heterozygotes. J Biol Chem 2007; 282:26517-27. [PMID: 17597066 DOI: 10.1074/jbc.m703029200] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Loss of one copy of the human ATP2C1 gene, encoding SPCA1 (secretory pathway Ca(2+)-ATPase isoform 1), causes Hailey-Hailey disease, a skin disorder. We performed targeted mutagenesis of the Atp2c1 gene in mice to analyze the functions of this Golgi membrane Ca(2+) pump. Breeding of heterozygous mutants yielded a normal Mendelian ratio among embryos on gestation day 9.5; however, null mutant (Spca1(-/-)) embryos exhibited growth retardation and did not survive beyond gestation day 10.5. Spca1(-/-) embryos had an open rostral neural tube, but hematopoiesis and cardiovascular development were ostensibly normal. Golgi membranes of Spca1(-/-) embryos were dilated, had fewer stacked leaflets, and were expanded in amount, consistent with increased Golgi biogenesis. The number of Golgi-associated vesicles was also increased, and rough endoplasmic reticulum had fewer ribosomes. Coated pits, junctional complexes, desmosomes, and basement membranes appeared normal in mutant embryos, indicating that processing and trafficking of proteins in the secretory pathway was not massively impaired. However, apoptosis was increased, possibly the result of secretory pathway stress, and a large increase in cytoplasmic lipid was observed in mutant embryos, consistent with impaired handling of lipid by the Golgi. Adult heterozygous mice appeared normal and exhibited no evidence of Hailey-Hailey disease; however, aged heterozygotes had an increased incidence of squamous cell tumors of keratinized epithelial cells of the skin and esophagus. These data show that loss of the Golgi Ca(2+) pump causes Golgi stress, expansion of the Golgi, increased apoptosis, and embryonic lethality and demonstrates that SPCA1 haploinsufficiency causes a genetic predisposition to cancer.
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MESH Headings
- Aging/genetics
- Aging/metabolism
- Aging/pathology
- Animals
- Apoptosis/genetics
- Basement Membrane/metabolism
- Basement Membrane/ultrastructure
- Calcium-Transporting ATPases/deficiency
- Calcium-Transporting ATPases/metabolism
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/metabolism
- Carcinoma, Squamous Cell/pathology
- Cardiovascular System/embryology
- Coated Pits, Cell-Membrane/genetics
- Coated Pits, Cell-Membrane/metabolism
- Coated Pits, Cell-Membrane/ultrastructure
- Desmosomes/genetics
- Desmosomes/metabolism
- Desmosomes/ultrastructure
- Embryo Loss/genetics
- Embryo Loss/metabolism
- Embryo Loss/pathology
- Endoplasmic Reticulum, Rough/genetics
- Endoplasmic Reticulum, Rough/metabolism
- Endoplasmic Reticulum, Rough/ultrastructure
- Esophageal Neoplasms/genetics
- Esophageal Neoplasms/metabolism
- Esophageal Neoplasms/pathology
- Female
- Genetic Predisposition to Disease
- Golgi Apparatus/metabolism
- Golgi Apparatus/ultrastructure
- Hematopoiesis/genetics
- Heterozygote
- Homozygote
- Humans
- Inbreeding
- Loss of Heterozygosity/genetics
- Male
- Mice
- Mice, Knockout
- Neural Tube Defects/embryology
- Neural Tube Defects/metabolism
- Neural Tube Defects/pathology
- Pemphigus, Benign Familial/genetics
- Pemphigus, Benign Familial/metabolism
- Pemphigus, Benign Familial/pathology
- Pregnancy
- Protein Transport/genetics
- Ribosomes/metabolism
- Secretory Vesicles/genetics
- Secretory Vesicles/metabolism
- Secretory Vesicles/ultrastructure
- Skin Neoplasms/genetics
- Skin Neoplasms/metabolism
- Skin Neoplasms/pathology
- Water-Electrolyte Balance/genetics
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Affiliation(s)
- Gbolahan W Okunade
- Department of Molecular Genetics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0524, USA
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125
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Abstract
Proteins synthesized in the endoplasmic reticulum (ER) are properly folded with the assistance of ER chaperones. Malfolded proteins are disposed of by ER-associated protein degradation (ERAD). When the amount of unfolded protein exceeds the folding capacity of the ER, human cells activate a defense mechanism called the ER stress response, which induces expression of ER chaperones and ERAD components and transiently attenuates protein synthesis to decrease the burden on the ER. It has been revealed that three independent response pathways separately regulate induction of the expression of chaperones, ERAD components, and translational attenuation. A malfunction of the ER stress response caused by aging, genetic mutations, or environmental factors can result in various diseases such as diabetes, inflammation, and neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, and bipolar disorder, which are collectively known as 'conformational diseases'. In this review, I will summarize recent progress in this field. Molecules that regulate the ER stress response would be potential candidates for drug targets in various conformational diseases.
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Affiliation(s)
- Hiderou Yoshida
- Department of Biophysics, Graduate School of Science, Kyoto University, Japan.
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126
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Lin X, Liu CC, Gao Q, Zhang X, Wu G, Lee WH. RINT-1 serves as a tumor suppressor and maintains Golgi dynamics and centrosome integrity for cell survival. Mol Cell Biol 2007; 27:4905-16. [PMID: 17470549 PMCID: PMC1951495 DOI: 10.1128/mcb.02396-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Faithful mitotic partitioning of the Golgi apparatus and the centrosome is critical for proper cell division. Although these two cytoplasmic organelles are probably coordinated during cell division, supporting evidence of this coordination is still largely lacking. Here, we show that the RAD50-interacting protein, RINT-1, is localized at the Golgi apparatus and the centrosome in addition to the endoplasmic reticulum. To examine the biological roles of RINT-1, we found that the homozygous deletion of Rint-1 caused early embryonic lethality at embryonic day 5 (E5) to E6 and the failure of blastocyst outgrowth ex vivo. About 81% of the Rint-1 heterozygotes succumbed to multiple tumor formation with haploinsufficiency during their average life span of 24 months. To pinpoint the cellular function of RINT-1, we found that RINT-1 depletion by RNA interference led to the loss of the pericentriolar positioning and dispersal of the Golgi apparatus and concurrent centrosome amplification during the interphase. Upon mitotic entry, RINT-1-deficient cells exhibited multiple abnormalities, including aberrant Golgi dynamics during early mitosis and defective reassembly at telophase, increased formation of multiple spindle poles, and frequent chromosome missegregation. Mitotic cells often underwent cell death in part due to the overwhelming cellular defects. Taken together, these findings suggest that RINT-1 serves as a novel tumor suppressor essential for maintaining the dynamic integrity of the Golgi apparatus and the centrosome, a prerequisite to their proper coordination during cell division.
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Affiliation(s)
- Xiaoqin Lin
- Department of Biological Chemistry, 124 Sprague Hall, 839 Medical Science Ct., University of California, Irvine, Irvine, CA 92697, USA
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127
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Bánhegyi G, Benedetti A, Csala M, Mandl J. Stress on redox. FEBS Lett 2007; 581:3634-40. [PMID: 17467703 DOI: 10.1016/j.febslet.2007.04.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Revised: 04/11/2007] [Accepted: 04/12/2007] [Indexed: 01/12/2023]
Abstract
Redox imbalance in the endoplasmic reticulum lumen is the most frequent cause of endoplasmic reticulum stress and consequent apoptosis. The mechanism involves the impairment of oxidative protein folding, the accumulation of unfolded/misfolded proteins in the lumen and the initiation of the unfolded protein response. The participation of several redox systems (glutathione, ascorbate, FAD, tocopherol, vitamin K) has been demonstrated in the process. Recent findings have attracted attention to the possible mechanistic role of luminal pyridine nucleotides in the endoplasmic reticulum stress. The aim of this minireview is to summarize the luminal redox systems and the redox sensing mechanisms of the endoplasmic reticulum.
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Affiliation(s)
- Gábor Bánhegyi
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, 1444 Budapest, POB 260, Hungary.
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128
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Wlodkowic D, Skommer J, Pelkonen J. Brefeldin A triggers apoptosis associated with mitochondrial breach and enhances HA14-1- and anti-Fas-mediated cell killing in follicular lymphoma cells. Leuk Res 2007; 31:1687-700. [PMID: 17428536 DOI: 10.1016/j.leukres.2007.03.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2006] [Revised: 02/27/2007] [Accepted: 03/02/2007] [Indexed: 12/01/2022]
Abstract
Follicular lymphoma (FL) remains a fatal disease of increasing worldwide incidence. Since patients with FL eventually develop resistance to conventional anticancer agents, and due to BCL-2 overexpression present with profoundly compromised execution of mitochondrial pathway of apoptosis, targeting alternative pathways of cell demise may appear therapeutically beneficial. Herein we report for the first time the effects of an ER-Golgi transport inhibitor, Brefeldin A (BFA), alone and in combination with a small molecule Bcl-2 inhibitor HA14-1 or agonistic anti-Fas mAb, in the recently established human FL cell lines. All cell lines tested were sensitive to BFA-induced cytotoxicity and apoptosis. Moreover BFA-induced cell death was associated with profound ER stress, mitochondrial breach and subsequent caspase cascade activation, including caspase 2 activation. Interestingly, BFA-induced ER stress did not result in appearance of autophagic morphology in FL cells. Of importance, small molecule Bcl-2 antagonist, HA14-1 and agonistic anti-Fas mAb significantly enhanced BFA-mediated cytotoxicity and apoptosis, revealing novel and previously unexplored means to enhance ER stress-mediated cell killing in follicular lymphoma cells.
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Affiliation(s)
- Donald Wlodkowic
- Institute of Clinical Sciences, Department of Clinical Microbiology, University of Kuopio, Kuopio, Finland.
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129
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Ouasti S, Matarrese P, Paddon R, Khosravi-Far R, Sorice M, Tinari A, Malorni W, Esposti MD. Death receptor ligation triggers membrane scrambling between Golgi and mitochondria. Cell Death Differ 2007; 14:453-61. [PMID: 17008914 PMCID: PMC2941902 DOI: 10.1038/sj.cdd.4402043] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Subcellular organelles such as mitochondria, endoplasmic reticulum (ER) and the Golgi complex are involved in the progression of the cell death programme. We report here that soon after ligation of Fas (CD95/Apo1) in type II cells, elements of the Golgi complex intermix with mitochondria. This mixing follows centrifugal dispersal of secretory membranes and reflects a global alteration of membrane traffic. Activation of apical caspases is instrumental for promoting the dispersal of secretory organelles, since caspase inhibition blocks the outward movement of Golgi-related endomembranes and reduces their mixing with mitochondria. Caspase inhibition also blocks the FasL-induced secretion of intracellular proteases from lysosomal compartments, outlining a novel aspect of death receptor signalling via apical caspases. Thus, our work unveils that Fas ligand-mediated apoptosis induces scrambling of mitochondrial and secretory organelles via a global alteration of membrane traffic that is modulated by apical caspases.
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Affiliation(s)
- S Ouasti
- Faculty of Life Sciences, The University of Manchester, Stopford Building, Oxford Road, Manchester, UK
| | - P Matarrese
- Department of Drug Research and Evaluation, Section of Cell Aging and Degeneration, Rome, Italy
| | - R Paddon
- Faculty of Life Sciences, The University of Manchester, Stopford Building, Oxford Road, Manchester, UK
| | - R Khosravi-Far
- Department of Pathology, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - M Sorice
- Department of Experimental Medicine and Pathology, Universita’ ‘La Sapienza’, Rome, Italy
| | - A Tinari
- Technology and Health, Istituto Superiore Sanita’, Rome, Italy
| | - W Malorni
- Department of Drug Research and Evaluation, Section of Cell Aging and Degeneration, Rome, Italy
| | - M Degli Esposti
- Faculty of Life Sciences, The University of Manchester, Stopford Building, Oxford Road, Manchester, UK
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130
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Gubser C, Bergamaschi D, Hollinshead M, Lu X, van Kuppeveld FJM, Smith GL. A new inhibitor of apoptosis from vaccinia virus and eukaryotes. PLoS Pathog 2007; 3:e17. [PMID: 17319741 PMCID: PMC1803007 DOI: 10.1371/journal.ppat.0030017] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Accepted: 12/21/2006] [Indexed: 01/28/2023] Open
Abstract
A new apoptosis inhibitor is described from vaccinia virus, camelpox virus, and eukaryotic cells. The inhibitor is a hydrophobic, multiple transmembrane protein that is resident in the Golgi and is named GAAP (Golgi anti-apoptotic protein). Stable expression of both viral GAAP (v-GAAP) and human GAAP (h-GAAP), which is expressed in all human tissues tested, inhibited apoptosis induced by intrinsic and extrinsic apoptotic stimuli. Conversely, knockout of h-GAAP by siRNA induced cell death by apoptosis. v-GAAP and h-GAAP display overlapping functions as shown by the ability of v-GAAP to complement for the loss of h-GAAP. Lastly, deletion of the v-GAAP gene from vaccinia virus did not affect virus replication in cell culture, but affected virus virulence in a murine infection model. This study identifies a new regulator of cell death that is highly conserved in evolution from plants to insects, amphibians, mammals, and poxviruses.
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Affiliation(s)
- Caroline Gubser
- Department of Virology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Daniele Bergamaschi
- Ludwig Institute for Cancer Research, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Michael Hollinshead
- Department of Virology, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Xin Lu
- Ludwig Institute for Cancer Research, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Frank J. M van Kuppeveld
- Department of Medical Microbiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Geoffrey L Smith
- Department of Virology, Faculty of Medicine, Imperial College London, London, United Kingdom
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131
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López-Hernández FJ, Ortiz MA, Piedrafita FJ. The extrinsic and intrinsic apoptotic pathways are differentially affected by temperature upstream of mitochondrial damage. Apoptosis 2007; 11:1339-47. [PMID: 16703261 DOI: 10.1007/s10495-006-7689-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
It is well known that mild hypothermia prevents neuronal cell death following cerebral ischemia, although it can also cause apoptosis in other cell types. Thus, incubation at room temperature (RT) has been shown to induce apoptosis in hematopoietic cells, including Jurkat T leukemia cells. To further understand the apoptotic events that can be activated at RT, we compared the induction of apoptosis by several apoptotic insults in Jurkat cells stimulated at 37 degrees C or RT. Retinoid-related molecules, which induce apoptosis via the intrinsic pathway, failed to induce apoptosis when cells were treated at RT, as determined by various apoptotic parameters including cytochrome c release and activation of caspase 3. In contrast, most apoptotic events were enhanced by lower temperatures when cells were stimulated with anti-Fas antibody via the extrinsic pathway. Ultraviolet radiation produced partial effects at RT, correlating with its capacity to activate both pathways. Our results indicate that the core caspase machinery is operational under mild hypothermia conditions. Experiments using purified recombinant caspases and cell-free assays confirmed that caspases are fully functional at RT. Other hallmark events of apoptosis, such as phosphatidylserine externalization and formation of apoptotic bodies were variably affected by RT in a stimulus-dependent manner, suggesting the existence of critical steps that are sensitive to temperature. Thus, analysis of apoptosis at RT might be useful to (i) discriminate between the extrinsic and intrinsic pathways in Jurkat cells treated with prospective stimuli, and (ii) to unravel temperature-sensitive steps of apoptotic signaling cascades.
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132
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Kamiya H, Zhang W, Sima AAF. Degeneration of the Golgi and neuronal loss in dorsal root ganglia in diabetic BioBreeding/Worcester rats. Diabetologia 2006; 49:2763-74. [PMID: 17047923 DOI: 10.1007/s00125-006-0379-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Accepted: 05/30/2006] [Indexed: 10/24/2022]
Abstract
AIMS/HYPOTHESIS The aim of this study was to evaluate the nature and extent of neuronal loss in dorsal root ganglia (DRG) in diabetic polyneuropathy. MATERIALS AND METHODS We examined 10-month diabetic BioBreeding/Worcester (BB/Wor) rats with respect to DRG ultrastructure and morphometry, sural nerve morphometry, pro- and anti-apoptotic proteins, the expression of neurotrophic factors and their receptors, and sensory nerve functions. RESULTS In diabetic rats, DRG neurons decreased to 73% of normal, owing to loss of substance P and calcitonin gene-related peptide-positive neurons. Levels of pro-apoptotic active caspase-3, Bax and low-affinity nerve growth factor (NGF) were increased in DRG. The concentration of anti-apoptotic heat shock protein (HSP) 70 in DRG was decreased, whereas concentrations of Bcl-xl and HSP27 were unaltered. Levels of poly(ADP-ribose) polymerase (PARP) and cleaved PARP were unaltered. Levels of NGF in sciatic nerve and concentrations of the high-affinity NGF receptor, insulin receptor and IGF-I receptor in DRG were significantly decreased. Sensory nerve conduction velocity decreased to 78% of normal. Hyperalgesia increased up to 6 months. Myelinated and unmyelinated fibre numbers of the sural nerve were significantly decreased in diabetic rats. DRG examinations revealed no evidence of apoptosis, mitochondrial changes or abnormalities of the endoplasmic reticulum. Instead, neurons demonstrated progressive vacuolar degenerative changes of the Golgi apparatus, with fragmentation and formation of large cytoplasmic vacuoles. These data show that sustained apoptotic stress is present in DRG of chronically diabetic BB/Wor rats, but fails to proceed to apoptotic cell death. CONCLUSIONS/INTERPRETATION Progressive DRG neuronal loss, particularly of small neurons, occurs in the type 1 diabetic BB/Wor rat. This is associated with neurotrophic withdrawal and progressive degeneration of the Golgi apparatus.
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Affiliation(s)
- H Kamiya
- Department of Pathology, Wayne State University, School of Medicine, Scott Hall 9275, 540 E. Canfield Avenue, Detroit, MI 48201, USA
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133
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Chowdhury I, Tharakan B, Bhat GK. Current concepts in apoptosis: the physiological suicide program revisited. Cell Mol Biol Lett 2006; 11:506-25. [PMID: 16977376 PMCID: PMC6275981 DOI: 10.2478/s11658-006-0041-3] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Accepted: 06/22/2006] [Indexed: 12/15/2022] Open
Abstract
Apoptosis, or programmed cell death (PCD), involves a complex network of biochemical pathways that normally ensure a homeostatic balance between cellular proliferation and turnover in nearly all tissues. Apoptosis is essential for the body, as its deregulation can lead to several diseases. It plays a major role in a variety of physiological events, including embryonic development, tissue renewal, hormone-induced tissue atrophy, removal of inflammatory cells, and the evolution of granulation tissue into scar tissue. It also has an essential role in wound repair. The various cellular and biochemical mechanisms involved in apoptosis are not fully understood. However, there are two major pathways, the extrinsic pathway (receptor-mediated apoptotic pathway) and the intrinsic pathway (mitochondria-mediated apoptotic pathway), which are both well established. The key component in both is the activation of the caspase cascade. Caspases belong to the family of proteases that ultimately, by cleaving a set of proteins, cause disassembly of the cell. Although the caspase-mediated proteolytic cascade represents a central point in the apoptotic response, its initiation is tightly regulated by a variety of other factors. Among them, Bcl-2 family proteins, TNF and p53 play pivotal roles in the regulation of caspase activation and in the regulation of apoptosis. This review summarizes the established concepts in apoptosis as a physiological cell suicide program, highlighting the recent and significant advances in its study.
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Affiliation(s)
- Indrajit Chowdhury
- Department of Obstetrics and Gynecology, Morehouse School of Medicine, Atlanta, GA USA
| | - Binu Tharakan
- Department of Neurology, Scott and White Clinic, The Texas A & M University Health Science Center, College of Medicine, Temple, Texas USA
| | - Ganapathy K. Bhat
- Department of Obstetrics and Gynecology, Morehouse School of Medicine, Atlanta, GA USA
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134
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Sbodio JI, Hicks SW, Simon D, Machamer CE. GCP60 preferentially interacts with a caspase-generated golgin-160 fragment. J Biol Chem 2006; 281:27924-31. [PMID: 16870622 DOI: 10.1074/jbc.m603276200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Golgin-160, a ubiquitous protein in vertebrates, localizes to the cytoplasmic face of the Golgi complex. Golgin-160 has a large coiled-coil C-terminal domain and a non-coiled-coil N-terminal ("head") domain. The head domain contains important motifs, including a nuclear localization signal, a Golgi targeting domain, and three aspartates that are recognized by caspases during apoptosis. Some of the caspase cleavage products accumulate in the nucleus when overexpressed. Expression of a non-cleavable form of golgin-160 impairs apoptosis induced by some pro-apoptotic stimuli; thus cleavage of golgin-160 appears to play a role in apoptotic signaling. We used a yeast two-hybrid assay to screen for interactors of the golgin-160 head and identified GCP60 (Golgi complex-associated protein of 60 kDa). Further analysis demonstrated that GCP60 interacts preferentially with one of the golgin-160 caspase cleavage fragments (residues 140-311). This strong interaction prevented the golgin-160 fragment from accumulating in the nucleus when this fragment and GCP60 were overexpressed. In addition, cells overexpressing GCP60 were more sensitive to apoptosis induced by staurosporine, suggesting that nuclear-localized golgin-160-(140-311) might promote cell survival. Our results suggest a potential mechanism for regulating the nuclear translocation and potential functions of golgin-160 fragments.
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Affiliation(s)
- Juan I Sbodio
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Gonatas NK, Stieber A, Gonatas JO. Fragmentation of the Golgi apparatus in neurodegenerative diseases and cell death. J Neurol Sci 2006; 246:21-30. [PMID: 16545397 DOI: 10.1016/j.jns.2006.01.019] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Revised: 12/08/2005] [Accepted: 01/23/2006] [Indexed: 10/24/2022]
Abstract
Fragmentation of the neuronal Golgi apparatus (GA) was reported in amyotrophic lateral sclerosis (ALS), corticobasal degeneration, Alzheimer's and Creutzfeldt-Jacob disease, and in spinocerebelar ataxia type 2 (SCA2). In transgenic mice expressing the G93A mutant of Cu/Zn superoxide dismutase (SOD1) of familial ALS (fALS), fragmentation of the GA of spinal cord motor neurons and aggregation of mutant protein were detected months before the onset of paralysis. Moreover, cells that expressed the G93A and G85R mutants of SOD1 showed fragmentation of the GA and decreased viability without apoptosis. We summarize here mechanisms involved in Golgi fragmentation implicating: (a) the dysregulation by mutant SOD1of the microtubule-destabilizing protein Stathmin, (b) the disruption by mutant SOD1of the neuronal cytoplasmic dynein, (c) the coprecipitation of mutant SOD1 with Hsp25 and Hsp27, (d) the reduction of detyrosinated microtubules by aggregated tau which resulted in non-apoptotic cell death and (e) the disruption by mutant growth hormone of the trafficking from the rough endoplasmic reticulum to the GA. The data indicate that neuronal Golgi fragmentation is an early and probably irreversible lesion in neurodegeneration, caused by a variety of mechanisms. Golgi fragmentation is not secondary to apoptosis but it may "trigger" apoptosis.
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Affiliation(s)
- Nicholas K Gonatas
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Medical Center, 609 Stellar Chance Laboratories, 422 Curie Boulevard, Philadelphia, PA 19104-6100, USA.
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Abstract
Coiled-coil and multisubunit tethers have emerged as key regulators of membrane traffic and organellar architecture. The restricted subcellular localization of tethers and their ability to interact with Rabs and soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) suggests that tethers participate in determining the specificity of membrane fusion. An accepted model of tether function considers them molecular “bridges” that link opposing membranes before SNARE pairing. This model has been extended by findings in various experimental systems, suggesting that tethers may have other functions. Recent reports implicate tethers in the assembly of SNARE complexes, cargo selection and transit, cytoskeletal events, and localized attachment of regulatory proteins. A concept of tethers as scaffolding machines that recruit protein components involved in varied cellular responses is emerging. In this model, tethers function as integration switches that simultaneously transmit information to coordinate distinct processes required for membrane traffic.
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Affiliation(s)
- Elizabeth Sztul
- Dept. of Cell Biology, Univ. of Alabama at Birmingham, 1918 Univ. Blvd., Birmingham, AL 35294, USA.
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