901
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Su B, Wang X, Zheng L, Perry G, Smith MA, Zhu X. Abnormal mitochondrial dynamics and neurodegenerative diseases. Biochim Biophys Acta Mol Basis Dis 2009; 1802:135-42. [PMID: 19799998 DOI: 10.1016/j.bbadis.2009.09.013] [Citation(s) in RCA: 212] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 09/10/2009] [Accepted: 09/22/2009] [Indexed: 12/23/2022]
Abstract
Mitochondrial dysfunction is a prominent feature of various neurodegenerative diseases. A deeper understanding of the remarkably dynamic nature of mitochondria, characterized by a delicate balance of fission and fusion, has helped to fertilize a recent wave of new studies demonstrating abnormal mitochondrial dynamics in neurodegenerative diseases. This review highlights mitochondrial dysfunction and abnormal mitochondrial dynamics in Alzheimer disease, Parkinson disease, amyotrophic lateral sclerosis, and Huntington disease and discusses how these abnormal mitochondrial dynamics may contribute to mitochondrial and neuronal dysfunction. We propose that abnormal mitochondrial dynamics represents a key common pathway that mediates or amplifies mitochondrial dysfunction and neuronal dysfunction during the course of neurodegeneration.
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Affiliation(s)
- Bo Su
- Department of Pathology, Case Western Reserve University, 2103 Cornell Road, Cleveland, OH 44106, USA
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902
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GDAP1 mutations differ in their effects on mitochondrial dynamics and apoptosis depending on the mode of inheritance. Neurobiol Dis 2009; 36:509-20. [PMID: 19782751 DOI: 10.1016/j.nbd.2009.09.011] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 09/10/2009] [Accepted: 09/20/2009] [Indexed: 12/12/2022] Open
Abstract
Mutations in the GDAP1 gene lead to recessively or dominantly inherited peripheral neuropathies (Charcot-Marie-Tooth disease; CMT). Here, we demonstrate that GDAP1 is a mitochondrial fission factor whose activity is dependent on the fission factors Drp1 and Fis1. Unlike other mitochondrial fission factors, GDAP1 overexpression or knockdown does not influence the susceptibility of cells to apoptotic stimuli. Recessively inherited CMT-associated forms of GDAP1 (rmGDAP1s) have reduced fission activity, whereas dominantly inherited forms (dmGDAP1s) interfere with mitochondrial fusion. Only the expression of dmGDAP1s increases the production of ROS, leads to uneven mitochondrial transmembrane potentials, and enhances the susceptibility to apoptotic stimuli. Taken together, our results indicate that wild-type GDAP1 promotes fission without increasing the risk of apoptosis. In CMT, recessive GDAP1 mutations are associated with reduced fission activity, while dominant mutations impair mitochondrial fusion and cause mitochondrial damage. Thus, different cellular mechanisms that disturb mitochondrial dynamics underlie the similar clinical manifestations caused by GDAP1 mutations, depending on the mode of inheritance.
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903
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Wakabayashi J, Zhang Z, Wakabayashi N, Tamura Y, Fukaya M, Kensler TW, Iijima M, Sesaki H. The dynamin-related GTPase Drp1 is required for embryonic and brain development in mice. ACTA ACUST UNITED AC 2009; 186:805-16. [PMID: 19752021 PMCID: PMC2753156 DOI: 10.1083/jcb.200903065] [Citation(s) in RCA: 528] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Brain-specific Drp1 knockout mice demonstrate that Drp1-mediated organelle division is important for development, mitochondrial morphogenesis, and apoptosis. The dynamin-related guanosine triphosphatase Drp1 mediates the division of mitochondria and peroxisomes. To understand the in vivo function of Drp1, complete and tissue-specific mouse knockouts of Drp1 were generated. Drp1-null mice die by embryonic day 11.5. This embryonic lethality is not likely caused by gross energy deprivation, as Drp1-null cells showed normal intracellular adenosine triphosphate levels. In support of the role of Drp1 in organelle division, mitochondria formed extensive networks, and peroxisomes were elongated in Drp1-null embryonic fibroblasts. Brain-specific Drp1 ablation caused developmental defects of the cerebellum in which Purkinje cells contained few giant mitochondria instead of the many short tubular mitochondria observed in control cells. In addition, Drp1-null embryos failed to undergo developmentally regulated apoptosis during neural tube formation in vivo. However, Drp1-null embryonic fibroblasts have normal responses to apoptotic stimuli in vitro, suggesting that the apoptotic function of Drp1 depends on physiological cues. These findings clearly demonstrate the physiological importance of Drp1-mediated organelle division in mice.
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Affiliation(s)
- Junko Wakabayashi
- Department of Cell Biology, School of Medicine, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
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904
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Abstract
Dynamin-related proteins (DRPs) can generate forces to remodel membranes. In cells, DRPs require additional proteins [DRP-associated proteins (DAPs)] to conduct their functions. To dissect the mechanistic role of a DAP, we used the yeast mitochondrial division machine as a model, which requires the DRP Dnm1, and two other proteins, Mdv1 and Fis1. Mdv1 played a postmitochondrial targeting role in division by specifically interacting and coassembling with the guanosine triphosphate-bound form of Dnm1. This regulated interaction nucleated and promoted the self-assembly of Dnm1 into helical structures, which drive membrane scission. The nucleation of DRP assembly probably represents a general regulatory strategy for this family of filament-forming proteins, similar to F-actin regulation.
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Affiliation(s)
- Laura L Lackner
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
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905
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Liesa M, Palacín M, Zorzano A. Mitochondrial dynamics in mammalian health and disease. Physiol Rev 2009; 89:799-845. [PMID: 19584314 DOI: 10.1152/physrev.00030.2008] [Citation(s) in RCA: 714] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The meaning of the word mitochondrion (from the Greek mitos, meaning thread, and chondros, grain) illustrates that the heterogeneity of mitochondrial morphology has been known since the first descriptions of this organelle. Such a heterogeneous morphology is explained by the dynamic nature of mitochondria. Mitochondrial dynamics is a concept that includes the movement of mitochondria along the cytoskeleton, the regulation of mitochondrial architecture (morphology and distribution), and connectivity mediated by tethering and fusion/fission events. The relevance of these events in mitochondrial and cell physiology has been partially unraveled after the identification of the genes responsible for mitochondrial fusion and fission. Furthermore, during the last decade, it has been identified that mutations in two mitochondrial fusion genes (MFN2 and OPA1) cause prevalent neurodegenerative diseases (Charcot-Marie Tooth type 2A and Kjer disease/autosomal dominant optic atrophy). In addition, other diseases such as type 2 diabetes or vascular proliferative disorders show impaired MFN2 expression. Altogether, these findings have established mitochondrial dynamics as a consolidated area in cellular physiology. Here we review the most significant findings in the field of mitochondrial dynamics in mammalian cells and their implication in human pathologies.
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Affiliation(s)
- Marc Liesa
- Institute for Research in Biomedicine (IRB Barcelona), CIBER de Diabetes y Enfermedades Metabólicas Asociadas, and Departament de Bioquímica i Biologia Molecular, Universitat de Barcelona, Barcelona 08028, Spain
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906
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Abstract
Mitochondria have been shown to play an important role in cell death in mammalian cells. However, the importance of mitochondria in Drosophila apoptosis is still under investigation. Many proteins involved in the regulation of apoptosis in mammals act at mitochondria or are released from mitochondria, resulting in caspase activation. In addition, these organelles undergo significant ultrastructural changes during apoptosis. This review highlights similarities and differences in the roles of mitochondria and mitochondrial factors in apoptosis between Drosophila and mammals. In Drosophila, many key regulators of apoptosis also appear to localize to this organelle, which also undergoes ultrastructural changes during apoptosis. Although many of the proteins important for the control of apoptosis in mammalian cells are conserved in Drosophila, the role that mitochondria play in apoptosis in this model system remains an area of controversy and active research.
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907
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Wasilewski M, Scorrano L. The changing shape of mitochondrial apoptosis. Trends Endocrinol Metab 2009; 20:287-94. [PMID: 19647447 DOI: 10.1016/j.tem.2009.03.007] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 03/05/2009] [Accepted: 03/05/2009] [Indexed: 10/20/2022]
Abstract
Mitochondria are key organelles in conversion of energy, regulation of cellular signaling and amplification of programmed cell death. The anatomy of the organelle matches this functional versatility in complexity and is modulated by the concerted action of proteins that impinge on its fusion-fission equilibrium. A growing body of evidence implicates changes in mitochondrial shape in the progression of apoptosis and, therefore, proteins governing such changes are likely candidates for involvement in pathogenetic mechanisms in neurodegeneration and cancer. Here, we discuss the recent advancements in our knowledge about the machinery that regulates mitochondrial shape and on the role of molecular mechanisms controlling mitochondrial morphology during cell death.
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Affiliation(s)
- Michał Wasilewski
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, 35129 Padova, Italy
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908
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Uo T, Dworzak J, Kinoshita C, Inman DM, Kinoshita Y, Horner PJ, Morrison RS. Drp1 levels constitutively regulate mitochondrial dynamics and cell survival in cortical neurons. Exp Neurol 2009; 218:274-85. [PMID: 19445933 PMCID: PMC2733949 DOI: 10.1016/j.expneurol.2009.05.010] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 05/02/2009] [Accepted: 05/08/2009] [Indexed: 10/20/2022]
Abstract
Mitochondria exist as dynamic networks that are constantly remodeled through the opposing actions of fusion and fission proteins. Changes in the expression of these proteins alter mitochondrial shape and size, and may promote or inhibit the propagation of apoptotic signals. Using mitochondrially targeted EGFP or DsRed2 to identify mitochondria, we observed a short, distinctly tubular mitochondrial morphology in postnatal cortical neurons in culture and in retinal ganglion cells in vivo, whereas longer, highly interconnected mitochondrial networks were detected in cortical astrocytes in vitro and non-neuronal cells in the retina in vivo. Differential expression patterns of fusion and fission proteins, in part, appear to determine these morphological differences as neurons expressed markedly high levels of Drp1 and OPA1 proteins compared to non-neuronal cells. This finding was corroborated using optic tissue samples. Moreover, cortical neurons expressed several splice variants of Drp1 including a neuron-specific isoform which incorporates exon 3. Knockdown or dominant-negative interference of endogenous Drp1 significantly increased mitochondrial length in both neurons and non-neuronal cells, but caused cell death only in cortical neurons. Conversely, depletion of the fusion protein, Mfn2, but not Mfn1, caused extensive mitochondrial fission and cell death. Thus, Drp1 and Mfn2 in normal cortical neurons not only regulate mitochondrial morphology, but are also required for cell survival. The present findings point to unique patterns of Drp1 expression and selective vulnerability to reduced levels of Drp1 expression/activity in neurons, and demonstrate that the regulation of mitochondrial dynamics must be tightly regulated in neurons.
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Affiliation(s)
- Takuma Uo
- Department of Neurological Surgery, University of Washington School of Medicine, Seattle, 98195-6470, USA
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909
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A hyperfused mitochondrial state achieved at G1-S regulates cyclin E buildup and entry into S phase. Proc Natl Acad Sci U S A 2009; 106:11960-5. [PMID: 19617534 DOI: 10.1073/pnas.0904875106] [Citation(s) in RCA: 500] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitochondria undergo fission-fusion events that render these organelles highly dynamic in cells. We report a relationship between mitochondrial form and cell cycle control at the G(1)-S boundary. Mitochondria convert from isolated, fragmented elements into a hyperfused, giant network at G(1)-S transition. The network is electrically continuous and has greater ATP output than mitochondria at any other cell cycle stage. Depolarizing mitochondria at early G(1) to prevent these changes causes cell cycle progression into S phase to be blocked. Inducing mitochondrial hyperfusion by acute inhibition of dynamin-related protein-1 (DRP1) causes quiescent cells maintained without growth factors to begin replicating their DNA and coincides with buildup of cyclin E, the cyclin responsible for G(1)-to-S phase progression. Prolonged or untimely formation of hyperfused mitochondria, through chronic inhibition of DRP1, causes defects in mitotic chromosome alignment and S-phase entry characteristic of cyclin E overexpression. These findings suggest a hyperfused mitochondrial system with specialized properties at G(1)-S is linked to cyclin E buildup for regulation of G(1)-to-S progression.
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910
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Mitochondrial fission factor Drp1 is essential for embryonic development and synapse formation in mice. Nat Cell Biol 2009; 11:958-66. [PMID: 19578372 DOI: 10.1038/ncb1907] [Citation(s) in RCA: 832] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 05/11/2009] [Indexed: 12/11/2022]
Abstract
Mitochondrial morphology is dynamically controlled by a balance between fusion and fission. The physiological importance of mitochondrial fission in vertebrates is less clearly defined than that of mitochondrial fusion. Here we show that mice lacking the mitochondrial fission GTPase Drp1 have developmental abnormalities, particularly in the forebrain, and die after embryonic day 12.5. Neural cell-specific (NS) Drp1(-/-) mice die shortly after birth as a result of brain hypoplasia with apoptosis. Primary culture of NS-Drp1(-/-) mouse forebrain showed a decreased number of neurites and defective synapse formation, thought to be due to aggregated mitochondria that failed to distribute properly within the cell processes. These defects were reflected by abnormal forebrain development and highlight the importance of Drp1-dependent mitochondrial fission within highly polarized cells such as neurons. Moreover, Drp1(-/-) murine embryonic fibroblasts and embryonic stem cells revealed that Drp1 is required for a normal rate of cytochrome c release and caspase activation during apoptosis, although mitochondrial outer membrane permeabilization, as examined by the release of Smac/Diablo and Tim8a, may occur independently of Drp1 activity.
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911
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Abstract
AIMS Mitochondrial fusion and fission are essential processes for preservation of normal mitochondrial function. We hypothesized that fusion proteins would be decreased in heart failure (HF), as the mitochondria in HF have been reported to be small and dysfunctional. METHODS AND RESULTS Expression of optic atrophy 1 (OPA1), a mitochondrial fusion protein, was decreased in both human and rat HF, as observed by western blotting. OPA1 is important for maintaining normal cristae structure and function, for preserving the inner membrane structure and for protecting cells from apoptosis. Confocal and electron microscopy studies demonstrated that the mitochondria in the failing hearts were small and fragmented, consistent with decreased fusion. OPA1 mRNA levels did not differ between failing and normal hearts, suggesting post-transcriptional control. Simulated ischaemia in the cardiac myogenic cell line H9c2 cells reduced OPA protein levels. Reduction of OPA1 expression with shRNA resulted in increased apoptosis and fragmentation of the mitochondria. Overexpression of OPA1 increased mitochondrial tubularity, but did not protect against simulated ischaemia-induced apoptosis. Cytochrome c release from the mitochondria was increased both with reduction in OPA1 and with overexpression of OPA1. CONCLUSION This is the first report, to our knowledge, of changes in mitochondrial fusion/fission proteins in cardiovascular disease. These changes have implications for mitochondrial function and apoptosis, contributing to the cell loss which is part of the downward progression of the failing heart.
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Affiliation(s)
- Le Chen
- Molecular and Cellular Cardiology, Department of Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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912
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Hom J, Sheu SS. Morphological dynamics of mitochondria--a special emphasis on cardiac muscle cells. J Mol Cell Cardiol 2009; 46:811-20. [PMID: 19281816 PMCID: PMC2995918 DOI: 10.1016/j.yjmcc.2009.02.023] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Revised: 02/22/2009] [Accepted: 02/25/2009] [Indexed: 01/10/2023]
Abstract
Mitochondria play a critical role in cellular energy metabolism, Ca(2+) homeostasis, reactive oxygen species generation, apoptosis, aging, and development. Many recent publications have shown that a continuous balance of fusion and fission of these organelles is important in maintaining their proper function. Therefore, there is a steep correlation between the form and function of mitochondria. Many major proteins involved in mitochondrial fusion and fission have been identified in different cell types, including heart. However, the functional role of mitochondrial dynamics in the heart remains, for the most part, unexplored. In this review we will cover the recent field of mitochondrial dynamics and its physiological and pathological implications, with a particular emphasis on the experimental and theoretical basis of mitochondrial dynamics in the heart.
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Affiliation(s)
- Jennifer Hom
- Department of Pharmacology and Physiology, Mitochondrial Research & Innovation Group, University of Rochester Medical Center, 601 Elmwood Avenue, Box 711, Rochester, NY 14642
| | - Shey-Shing Sheu
- Department of Pharmacology and Physiology, Mitochondrial Research & Innovation Group, University of Rochester Medical Center, 601 Elmwood Avenue, Box 711, Rochester, NY 14642
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913
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Shroff EH, Snyder CM, Budinger GRS, Jain M, Chew TL, Khuon S, Perlman H, Chandel NS. BH3 peptides induce mitochondrial fission and cell death independent of BAX/BAK. PLoS One 2009; 4:e5646. [PMID: 19468307 PMCID: PMC2681411 DOI: 10.1371/journal.pone.0005646] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Accepted: 04/18/2009] [Indexed: 11/18/2022] Open
Abstract
BH3 only proteins trigger cell death by interacting with pro- and anti-apoptotic members of the BCL-2 family of proteins. Here we report that BH3 peptides corresponding to the death domain of BH3-only proteins, which bind all the pro-survival BCL-2 family proteins, induce cell death in the absence of BAX and BAK. The BH3 peptides did not cause the release of cytochrome c from isolated mitochondria or from mitochondria in cells. However, the BH3 peptides did cause a decrease in mitochondrial membrane potential but did not induce the opening of the mitochondrial permeability transition pore. Interestingly, the BH3 peptides induced mitochondria to undergo fission in the absence of BAX and BAK. The binding of BCL-XL with dynamin-related protein 1 (DRP1), a GTPase known to regulate mitochondrial fission, increased in the presence of BH3 peptides. These results suggest that pro-survival BCL-2 proteins regulate mitochondrial fission and cell death in the absence of BAX and BAK.
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Affiliation(s)
- Emelyn H. Shroff
- Department of Medicine, Northwestern University Medical School, Chicago, Illinois, United States of America
| | - Colleen M. Snyder
- Department of Medicine, Northwestern University Medical School, Chicago, Illinois, United States of America
| | - G. R. Scott Budinger
- Department of Medicine, Northwestern University Medical School, Chicago, Illinois, United States of America
- Department of Cell and Molecular Biology Northwestern University Medical School, Chicago, Illinois, United States of America
| | - Manu Jain
- Department of Medicine, Northwestern University Medical School, Chicago, Illinois, United States of America
- Department of Cell and Molecular Biology Northwestern University Medical School, Chicago, Illinois, United States of America
| | - Teng-Leong Chew
- Cell imaging facility, Northwestern University Medical School, Chicago, Illinois, United States of America
- Department of Cell and Molecular Biology Northwestern University Medical School, Chicago, Illinois, United States of America
| | - Satya Khuon
- Cell imaging facility, Northwestern University Medical School, Chicago, Illinois, United States of America
- Department of Cell and Molecular Biology Northwestern University Medical School, Chicago, Illinois, United States of America
| | - Harris Perlman
- Department of Medicine, Northwestern University Medical School, Chicago, Illinois, United States of America
| | - Navdeep S. Chandel
- Department of Medicine, Northwestern University Medical School, Chicago, Illinois, United States of America
- Department of Cell and Molecular Biology Northwestern University Medical School, Chicago, Illinois, United States of America
- * E-mail:
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914
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Jourdain A, Martinou JC. Mitochondrial outer-membrane permeabilization and remodelling in apoptosis. Int J Biochem Cell Biol 2009; 41:1884-9. [PMID: 19439192 DOI: 10.1016/j.biocel.2009.05.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 05/01/2009] [Accepted: 05/04/2009] [Indexed: 11/18/2022]
Abstract
Many human pathologies are associated with defects in mitochondria such as diabetes, neurodegenerative diseases or cancer. This tiny organelle is involved in a plethora of processes in mammalian cells, including energy production, lipid metabolism and cell death. In the so-called intrinsic apoptotic pathway, the outer mitochondrial membrane (MOM) is premeabilized by the pro-apoptotic Bcl-2 members Bax and Bak, allowing the release of apoptogenic factors such as cytochrome c from the inter-membrane space into the cytosol. At the same time, mitochondria fragment in response to Drp-1 activation suggesting that mitochondrial fission could play a role in mitochondrial outer-membrane permeabilization (MOMP). In this review, we will discuss the link that could exist between mitochondrial fission and fusion machinery, Bcl-2 family members and MOMP.
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Affiliation(s)
- Alexis Jourdain
- Department of Cell Biology, University of Geneva, Quai Ernest-Ansermet 30, 1211 Geneva 4, Switzerland
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915
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916
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Brooks C, Wei Q, Cho SG, Dong Z. Regulation of mitochondrial dynamics in acute kidney injury in cell culture and rodent models. J Clin Invest 2009; 119:1275-85. [PMID: 19349686 DOI: 10.1172/jci37829] [Citation(s) in RCA: 616] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 02/18/2009] [Indexed: 12/22/2022] Open
Abstract
The mechanism of mitochondrial damage, a key contributor to renal tubular cell death during acute kidney injury, remains largely unknown. Here, we have demonstrated a striking morphological change of mitochondria in experimental models of renal ischemia/reperfusion and cisplatin-induced nephrotoxicity. This change contributed to mitochondrial outer membrane permeabilization, release of apoptogenic factors, and consequent apoptosis. Following either ATP depletion or cisplatin treatment of rat renal tubular cells, mitochondrial fragmentation was observed prior to cytochrome c release and apoptosis. This mitochondrial fragmentation was inhibited by Bcl2 but not by caspase inhibitors. Dynamin-related protein 1 (Drp1), a critical mitochondrial fission protein, translocated to mitochondria early during tubular cell injury, and both siRNA knockdown of Drp1 and expression of a dominant-negative Drp1 attenuated mitochondrial fragmentation, cytochrome c release, caspase activation, and apoptosis. Further in vivo analysis revealed that mitochondrial fragmentation also occurred in proximal tubular cells in mice during renal ischemia/reperfusion and cisplatin-induced nephrotoxicity. Notably, both tubular cell apoptosis and acute kidney injury were attenuated by mdivi-1, a newly identified pharmacological inhibitor of Drp1. This study demonstrates a rapid regulation of mitochondrial dynamics during acute kidney injury and identifies mitochondrial fragmentation as what we believe to be a novel mechanism contributing to mitochondrial damage and apoptosis in vivo in mouse models of disease.
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Affiliation(s)
- Craig Brooks
- Department of Cellular Biology and Anatomy, Medical College of Georgia, and Charlie Norwood VA Medical Center, Augusta, 30912, USA
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917
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Berman SB, Chen YB, Qi B, McCaffery JM, Rucker EB, Goebbels S, Nave KA, Arnold BA, Jonas EA, Pineda FJ, Hardwick JM. Bcl-x L increases mitochondrial fission, fusion, and biomass in neurons. J Cell Biol 2009; 184:707-19. [PMID: 19255249 PMCID: PMC2686401 DOI: 10.1083/jcb.200809060] [Citation(s) in RCA: 181] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 01/22/2009] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial fission and fusion are linked to synaptic activity in healthy neurons and are implicated in the regulation of apoptotic cell death in many cell types. We developed fluorescence microscopy and computational strategies to directly measure mitochondrial fission and fusion frequencies and their effects on mitochondrial morphology in cultured neurons. We found that the rate of fission exceeds the rate of fusion in healthy neuronal processes, and, therefore, the fission/fusion ratio alone is insufficient to explain mitochondrial morphology at steady state. This imbalance between fission and fusion is compensated by growth of mitochondrial organelles. Bcl-x(L) increases the rates of both fusion and fission, but more important for explaining the longer organelle morphology induced by Bcl-x(L) is its ability to increase mitochondrial biomass. Deficits in these Bcl-x(L)-dependent mechanisms may be critical in neuronal dysfunction during the earliest phases of neurodegeneration, long before commitment to cell death.
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Affiliation(s)
- Sarah B. Berman
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, and Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205
- Department of Neurology and Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205
- Department of Neurology, Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA 15260
| | - Ying-bei Chen
- Department of Neurology and Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Bing Qi
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, and Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205
| | - J. Michael McCaffery
- Department of Biology, and the Integrated Imaging Center, Johns Hopkins University, Baltimore, MD 21218
| | - Edmund B. Rucker
- Animal Sciences Unit, University of Missouri, Columbia, MO 65211
| | - Sandra Goebbels
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, D-37075 Goettingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, D-37075 Goettingen, Germany
| | - Beth A. Arnold
- Department of Neurology, Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA 15260
| | | | - Fernando J. Pineda
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, and Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205
| | - J. Marie Hardwick
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, and Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205
- Department of Neurology and Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205
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918
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Jezek P, Plecitá-Hlavatá L. Mitochondrial reticulum network dynamics in relation to oxidative stress, redox regulation, and hypoxia. Int J Biochem Cell Biol 2009; 41:1790-804. [PMID: 19703650 DOI: 10.1016/j.biocel.2009.02.014] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 02/17/2009] [Accepted: 02/19/2009] [Indexed: 02/03/2023]
Abstract
A single mitochondrial network in the cell undergoes constant fission and fusion primarily depending on the local GTP gradients and the mitochondrial energetics. Here we overview the main properties and regulation of pro-fusion and pro-fission mitodynamins, i.e. dynamins-related GTPases responsible for mitochondrial shape-forming, such as pro-fusion mitofusins MFN1, MFN2, and the inner membrane-residing long OPA1 isoforms, and pro-fission mitodynamins FIS1, MFF, and DRP1 multimers required for scission. Notably, the OPA1 cleavage into non-functional short isoforms at a diminished ATP level (collapsed membrane potential) and the DRP1 recruitment upon phosphorylation by various kinases are overviewed. Possible responses of mitodynamins to the oxidative stress, hypoxia, and concomitant mtDNA mutations are also discussed. We hypothesize that the increased GTP formation within the Krebs cycle followed by the GTP export via the ADP/ATP carrier shift the balance between fission and fusion towards fusion by activating the GTPase domain of OPA1 located in the peripheral intermembrane space (PIMS). Since the protein milieu of PIMS is kept at the prevailing oxidized redox potential by the TOM, MIA40 and ALR/Erv1 import-redox trapping system, redox regulations shift the protein environment of PIMS to a more reduced state due to the higher substrate load and increased respiration. A higher cytochrome c turnover rate may prevent electron transfer from ALR/Erv1 to cytochrome c. Nevertheless, the putative links between the mitodynamin responses, mitochondrial morphology and the changes in the mitochondrial bioenergetics, superoxide production, and hypoxia are yet to be elucidated, including the precise basis for signaling by the mitochondrion-derived vesicles.
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Affiliation(s)
- Petr Jezek
- Department of Membrane Transport Biophysics, No. 75, Institute of Physiology, v.v.i., Academy of Sciences of the Czech Republic, Vídenská 1083, CZ 14220 Prague, Czech Republic.
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919
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Parsons MJ, Green DR. Mitochondria and apoptosis: a quick take on a long view. F1000 BIOLOGY REPORTS 2009; 1:17. [PMID: 20948669 PMCID: PMC2920673 DOI: 10.3410/b1-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Fifteen years of apoptosis research have led to the widely accepted idea that the major form of programmed cell death in mammals proceeds via the mitochondria, and that mitochondrial control of apoptosis is regulated by a specialized family of proteins known as the Bcl-2 family. Here we will consider some very recent data that has shed new insight into the regulation of these proteins and the impact of mitochondrial dynamics on mitochondrial outer membrane permeabilization (MOMP) and apoptosis.
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Affiliation(s)
- Melissa J Parsons
- Department of Immunology, St Jude Children's Research Hospital 262 Danny Thomas Place, Memphis, TN 38105 USA
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920
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Etxebarria A, Terrones O, Yamaguchi H, Landajuela A, Landeta O, Antonsson B, Wang HG, Basañez G. Endophilin B1/Bif-1 stimulates BAX activation independently from its capacity to produce large scale membrane morphological rearrangements. J Biol Chem 2009; 284:4200-12. [PMID: 19074440 PMCID: PMC3837389 DOI: 10.1074/jbc.m808050200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 12/05/2008] [Indexed: 01/09/2023] Open
Abstract
Endophilin B1/BAX-interacting factor 1 (Bif-1) is a protein that cooperates with dynamin-like protein 1 (DLP1/Drp1) to maintain normal mitochondrial outer membrane (MOM) dynamics in healthy cells and also contributes to BAX-driven MOM permeabilization (MOMP), the irreversible commitment point to cell death for the majority of apoptotic stimuli. However, despite its importance, exactly how Bif-1 fulfils its proapoptotic role is unknown. Here, we demonstrate that the stimulatory effect of Bif-1 on BAX-driven MOMP and on BAX conformational activation observed in intact cells during apoptosis can be recapitulated in a simplified system consisting of purified proteins and MOM-like liposomes. In this reconstituted model system the N-BAR domain of Bif-1 reproduced the stimulatory effect of Bif-1 on functional BAX activation. This process was dependent on physical interaction between Bif-1 N-BAR and BAX as well as on the presence of the mitochondrion-specific lipid cardiolipin. Despite that Bif-1 N-BAR produced large scale morphological rearrangements in MOM-like liposomes, this phenomenon could be separated from functional BAX activation. Furthermore, DLP1 also caused global morphological changes in MOM-like liposomes, but DLP1 did not stimulate BAX-permeabilizing function in the absence or presence of Bif-1. Taken together, our findings not only provide direct evidence for a functional interplay between Bif-1, BAX, and cardiolipin during MOMP but also add significantly to the growing body of evidence indicating that components of the mitochondrial morphogenesis machinery possess proapoptotic functions that are independent from their recognized roles in normal mitochondrial dynamics.
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Affiliation(s)
- Aitor Etxebarria
- From the Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Cientificas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, P. O. Box 644, 48080 Bilbao, Spain
| | - Oihana Terrones
- From the Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Cientificas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, P. O. Box 644, 48080 Bilbao, Spain
| | - Hirohito Yamaguchi
- the University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030
| | - Ane Landajuela
- From the Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Cientificas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, P. O. Box 644, 48080 Bilbao, Spain
| | - Olatz Landeta
- From the Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Cientificas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, P. O. Box 644, 48080 Bilbao, Spain
| | - Bruno Antonsson
- Merck Serono International S. A., 9 chemin des Mines, 1202 Geneva, Switzerland and
| | - Hong-Gang Wang
- the Department of Pharmacology, Penn State College of Medicine, Hershey, Pennsylvania 17033
| | - Gorka Basañez
- From the Unidad de Biofísica, Centro Mixto Consejo Superior de Investigaciones Cientificas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, P. O. Box 644, 48080 Bilbao, Spain
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921
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Wang JX, Li Q, Li PF. Apoptosis Repressor with Caspase Recruitment Domain Contributes to Chemotherapy Resistance by Abolishing Mitochondrial Fission Mediated by Dynamin-Related Protein-1. Cancer Res 2009; 69:492-500. [DOI: 10.1158/0008-5472.can-08-2962] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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922
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Lackner LL, Nunnari JM. The molecular mechanism and cellular functions of mitochondrial division. Biochim Biophys Acta Mol Basis Dis 2008; 1792:1138-44. [PMID: 19100831 DOI: 10.1016/j.bbadis.2008.11.011] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 11/19/2008] [Accepted: 11/20/2008] [Indexed: 11/27/2022]
Abstract
Mitochondria are highly dynamic organelles that continuously divide and fuse. These dynamic processes regulate the size, shape, and distribution of the mitochondrial network. In addition, mitochondrial division and fusion play critical roles in cell physiology. This review will focus on the dynamic process of mitochondrial division, which is highly conserved from yeast to humans. We will discuss what is known about how the essential components of the division machinery function to mediate mitochondrial division and then focus on proteins that have been implicated in division but whose functions remain unclear. We will then briefly discuss the cellular functions of mitochondrial division and the problems that arise when division is disrupted.
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Affiliation(s)
- Laura L Lackner
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
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923
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Cheng WC, Teng X, Park HK, Tucker CM, Dunham MJ, Hardwick JM. Fis1 deficiency selects for compensatory mutations responsible for cell death and growth control defects. Cell Death Differ 2008; 15:1838-46. [PMID: 18756280 PMCID: PMC2631236 DOI: 10.1038/cdd.2008.117] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Genetic mutations affecting mitochondrial fission and fusion proteins cause human neurological disorders, but are assumed to be well tolerated in yeast. The conserved mitochondrial fission protein Dnm1/Drp1 is required for normal mitochondrial division, but also promotes cell death in mammals and yeast. Fis1, an outer mitochondrial membrane-anchored receptor for Dnm1/Drp1, also can promote cell death in mammals, but appears to have prosurvival activity in yeast. Here we report that deletion of the FIS1 gene in yeast consistently results in acquisition of a secondary mutation that confers sensitivity to cell death. In several independently derived FIS1 knockouts, tiling arrays and genomic sequencing identified the secondary mutation as a premature termination in the same stress-response gene, WHI2. The WHI2 mutation rescues the mitochondrial respiratory defect (petite formation) caused by FIS1 deficiency, but also causes a failure to suppress cell growth during amino-acid deprivation. Thus, loss of Fis1 drives the selection for specific compensatory mutations that confer defective growth control and cell death regulation, characteristic of human tumor cells. The important long-term survival function of Fis1 that is compensated by WHI2 mutation appears to be independent of fission factor Dnm1/Drp1 and its adaptor Mdv1, but may be mediated through a second adaptor Caf4, as WHI2 is also mutated in a CAF4 knockout.
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Affiliation(s)
- W-C Cheng
- W Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
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924
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Dave Z, Byfield M, Bossy-Wetzel E. Assessing mitochondrial outer membrane permeabilization during apoptosis. Methods 2008; 46:319-23. [DOI: 10.1016/j.ymeth.2008.10.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 10/16/2008] [Accepted: 10/17/2008] [Indexed: 10/21/2022] Open
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925
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Knott AB, Bossy-Wetzel E. Impairing the mitochondrial fission and fusion balance: a new mechanism of neurodegeneration. Ann N Y Acad Sci 2008; 1147:283-92. [PMID: 19076450 PMCID: PMC2605288 DOI: 10.1196/annals.1427.030] [Citation(s) in RCA: 196] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mitochondrial dysfunction is a common characteristic of all neurodegenerative diseases. However, the cause of this dysfunction remains a mystery. Here, we discuss the potential role of mitochondrial fission and fusion in the onset and progression of neurodegenerative diseases. Specifically, we propose that an imbalance in mitochondrial fission and fusion may underlie both familial and sporadic neurodegenerative disorders. There is substantial evidence that links disruption of the mitochondrial fission and fusion equilibrium, resulting in abnormally long or short mitochondria, to neurodegeneration. First, hereditary mutations in the mitochondrial fusion GTPases optic atrophy-1 and mitofusin-2 cause neuropathies in humans. In addition, recent findings report increased mitochondrial fission in Parkinson's disease (PD) models and induction of mitochondrial fission by two proteins, PTEN-induced kinase 1 and parkin, which are mutant in familial forms of PD. Furthermore, mutant huntingtin, the disease-causing protein in Huntington's disease, alters mitochondrial morphology and dynamics. Rotenone, a pesticide and inducer of PD symptoms, and amyloid-beta peptide, which is causally linked to Alzheimer's disease, initiate mitochondrial fission. Finally, mitochondrial fission is an early event in ischemic stroke and diabetic neuropathies. In sum, a growing body of research suggests that a better understanding of mitochondrial fission and fusion and the regulatory factors involved may lead to improved treatments and cures for neurodegenerative diseases.
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Affiliation(s)
- Andrew B. Knott
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida
| | - Ella Bossy-Wetzel
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida
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926
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Tan FJ, Husain M, Manlandro CM, Koppenol M, Fire AZ, Hill RB. CED-9 and mitochondrial homeostasis in C. elegans muscle. J Cell Sci 2008; 121:3373-82. [PMID: 18827010 PMCID: PMC2785848 DOI: 10.1242/jcs.032904] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial homeostasis reflects a dynamic balance between membrane fission and fusion events thought essential for mitochondrial function. We report here that altered expression of the C. elegans BCL2 homolog CED-9 affects both mitochondrial fission and fusion. Although striated muscle cells lacking CED-9 have no alteration in mitochondrial size or ultrastructure, these cells appear more sensitive to mitochondrial fragmentation. By contrast, increased CED-9 expression in these cells produces highly interconnected mitochondria. This mitochondrial phenotype is partially suppressed by increased expression of the dynamin-related GTPase DRP-1, with suppression dependent on the BH3 binding pocket of CED-9. This suppression suggests that CED-9 directly regulates DRP-1, a model supported by our finding that CED-9 activates the GTPase activity of human DRP1. Thus, CED-9 is capable of regulating the mitochondrial fission-fusion cycle but is not essential for either fission or fusion.
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Affiliation(s)
- Frederick J. Tan
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Michelle Husain
- Integrated Imaging Center, Johns Hopkins University, Baltimore, MD 21218, USA
| | | | - Marijke Koppenol
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Andrew Z. Fire
- Departments of Pathology and Genetics, Stanford University SOM, Stanford, CA 94305, USA
| | - R. Blake Hill
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
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927
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Sheridan C, Delivani P, Cullen SP, Martin SJ. Bax- or Bak-induced mitochondrial fission can be uncoupled from cytochrome C release. Mol Cell 2008; 31:570-585. [PMID: 18722181 DOI: 10.1016/j.molcel.2008.08.002] [Citation(s) in RCA: 214] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 04/17/2008] [Accepted: 08/04/2008] [Indexed: 10/21/2022]
Abstract
Bax and Bak promote apoptosis by perturbing the permeability of the mitochondrial outer membrane and facilitating the release of cytochrome c by a mechanism that is still poorly defined. During apoptosis, Bax and Bak also promote fragmentation of the mitochondrial network, possibly by activating the mitochondrial fission machinery. It has been proposed that Bax/Bak-induced mitochondrial fission may be required for release of cytochrome c from the mitochondrial intermembrane space, although this has been a subject of debate. Here we show that Bcl-xL, as well as other members of the apoptosis-inhibitory subset of the Bcl-2 family, antagonized Bax and/or Bak-induced cytochrome c release but failed to block mitochondrial fragmentation associated with Bax/Bak activation. These data suggest that Bax/Bak-initiated remodeling of mitochondrial networks and cytochrome c release are separable events and that Bcl-2 family proteins can influence mitochondrial fission-fusion dynamics independent of apoptosis.
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Affiliation(s)
- Clare Sheridan
- Molecular Cell Biology Laboratory, Department of Genetics, The Smurfit Institute, Trinity College, Dublin 2, Ireland
| | - Petrina Delivani
- Molecular Cell Biology Laboratory, Department of Genetics, The Smurfit Institute, Trinity College, Dublin 2, Ireland
| | - Sean P Cullen
- Molecular Cell Biology Laboratory, Department of Genetics, The Smurfit Institute, Trinity College, Dublin 2, Ireland
| | - Seamus J Martin
- Molecular Cell Biology Laboratory, Department of Genetics, The Smurfit Institute, Trinity College, Dublin 2, Ireland.
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928
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Breckenridge DG, Kang BH, Kokel D, Mitani S, Staehelin LA, Xue D. Caenorhabditis elegans drp-1 and fis-2 regulate distinct cell-death execution pathways downstream of ced-3 and independent of ced-9. Mol Cell 2008; 31:586-597. [PMID: 18722182 PMCID: PMC2548325 DOI: 10.1016/j.molcel.2008.07.015] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 05/12/2008] [Accepted: 07/28/2008] [Indexed: 12/31/2022]
Abstract
The dynamin family of GTPases regulate mitochondrial fission and fusion processes and have been implicated in controlling the release of caspase activators from mitochondria during apoptosis. Here we report that profusion genes fzo-1 and eat-3 or the profission gene drp-1 are not required for apoptosis activation in C. elegans. However, minor proapoptotic roles for drp-1 and fis-2, a homolog of human Fis1, are revealed in sensitized genetic backgrounds. drp-1 and fis-2 function independent of one another and the Bcl-2 homolog CED-9 and downstream of the CED-3 caspase to promote elimination of mitochondria in dying cells, an event that could facilitate cell-death execution. Interestingly, CED-3 can cleave DRP-1, which appears to be important for DRP-1's proapoptotic function, but not its mitochondria fission function. Our findings demonstrate that mitochondria dynamics do not regulate apoptosis activation in C. elegans and reveal distinct roles for drp-1 and fis-2 as mediators of cell-death execution downstream of caspase activation.
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Affiliation(s)
- David G Breckenridge
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Byung-Ho Kang
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA; Department of Microbiology and Cell Science, Integrated Center for Biotechnology Research, University of Florida, Gainesville, FL 32608, USA
| | - David Kokel
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Shohei Mitani
- Department of Physiology, Tokyo Women's Medical University, School of Medicine, and CREST, JST, Tokyo, 162-8666, Japan
| | - L Andrew Staehelin
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Ding Xue
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
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929
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Abstract
In healthy cells, mitochondria continually divide and fuse to form a dynamic interconnecting network. The molecular machinery that mediates this organelle fission and fusion is necessary to maintain mitochondrial integrity, perhaps by facilitating DNA or protein quality control. This network disintegrates during apoptosis at the time of cytochrome c release and prior to caspase activation, yielding more numerous and smaller mitochondria. Recent work shows that proteins involved in mitochondrial fission and fusion also actively participate in apoptosis induction. This review will cover the recent advances and presents competing models on how the mitochondrial fission and fusion machinery may intersect apoptosis pathways.
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Affiliation(s)
- Der-Fen Suen
- Biochemistry Section, Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
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930
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Abstract
Cytochrome c is primarily known for its function in the mitochondria as a key participant in the life-supporting function of ATP synthesis. However, when a cell receives an apoptotic stimulus, cytochrome c is released into the cytosol and triggers programmed cell death through apoptosis. The release of cytochrome c and cytochrome-c-mediated apoptosis are controlled by multiple layers of regulation, the most prominent players being members of the B-cell lymphoma protein-2 (BCL2) family. As well as its role in canonical intrinsic apoptosis, cytochrome c amplifies signals that are generated by other apoptotic pathways and participates in certain non-apoptotic functions.
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931
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Cheng WC, Leach KM, Hardwick JM. Mitochondrial death pathways in yeast and mammalian cells. BIOCHIMICA ET BIOPHYSICA ACTA 2008; 1783:1272-9. [PMID: 18477482 PMCID: PMC2519237 DOI: 10.1016/j.bbamcr.2008.04.012] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 04/14/2008] [Accepted: 04/25/2008] [Indexed: 12/30/2022]
Abstract
In mammals, mitochondria are important mediators of programmed cell death, and this process is often regulated by Bcl-2 family proteins. However, a role for mitochondria-mediated cell death in non-mammalian species is more controversial. New evidence from a variety of sources suggests that mammalian mitochondrial fission/division proteins also have the capacity to promote programmed cell death, which may involve interactions with Bcl-2 family proteins. Homologues of these fission factors and several additional mammalian cell death regulators are conserved in flies, worms and yeast, and have been suggested to regulate programmed cell death in these species as well. However, the molecular mechanisms by which these phylogenetically conserved proteins contribute to cell death are not known for any species. Some have taken the conserved pro-death activity of mitochondrial fission factors to mean that mitochondrial fission per se, or failed attempts to undergo fission, are directly involved in cell death. Other evidence suggests that the fission function and the cell death function of these factors are separable. Here we consider the evidence for these arguments and their implications regarding the origins of programmed cell death.
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Affiliation(s)
- Wen-Chih Cheng
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205 USA
| | - Kelly M. Leach
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205 USA
| | - J. Marie Hardwick
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205 USA
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932
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Berman SB, Pineda FJ, Hardwick JM. Mitochondrial fission and fusion dynamics: the long and short of it. Cell Death Differ 2008; 15:1147-52. [PMID: 18437161 PMCID: PMC2614113 DOI: 10.1038/cdd.2008.57] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Maintenance of functional mitochondria requires fusion and fission of these dynamic organelles. The proteins that regulate mitochondrial dynamics are now associated with a broad range of cellular functions. Mitochondrial fission and fusion are often viewed as a finely tuned balance within cells, yet an integrated and quantitative understanding of how these processes interact with each other and with other mitochondrial and cellular processes is not well formulated. Direct visual observation of mitochondrial fission and fusion events, together with computational approaches promise to provide new insight.
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Affiliation(s)
- SB Berman
- Pittsburgh Institute for Neurodegenerative Diseases and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - FJ Pineda
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - JM Hardwick
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD 21205, USA
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933
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A mitochondrial block and expression of XIAP lead to resistance to TRAIL-induced apoptosis during progression to metastasis of a colon carcinoma. Oncogene 2008; 27:6012-22. [DOI: 10.1038/onc.2008.197] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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934
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