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Means RE, Katz SG. Balancing life and death: BCL-2 family members at diverse ER-mitochondrial contact sites. FEBS J 2022; 289:7075-7112. [PMID: 34668625 DOI: 10.1111/febs.16241] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/11/2021] [Accepted: 10/19/2021] [Indexed: 01/13/2023]
Abstract
The outer mitochondrial membrane is a busy place. One essential activity for cellular survival is the regulation of membrane integrity by the BCL-2 family of proteins. Another critical facet of the outer mitochondrial membrane is its close approximation with the endoplasmic reticulum. These mitochondrial-associated membranes (MAMs) occupy a significant fraction of the mitochondrial surface and serve as key signaling hubs for multiple cellular processes. Each of these pathways may be considered as forming their own specialized MAM subtype. Interestingly, like membrane permeabilization, most of these pathways play critical roles in regulating cellular survival and death. Recently, the pro-apoptotic BCL-2 family member BOK has been found within MAMs where it plays important roles in their structure and function. This has led to a greater appreciation that multiple BCL-2 family proteins, which are known to participate in numerous functions throughout the cell, also have roles within MAMs. In this review, we evaluate several MAM subsets, their role in cellular homeostasis, and the contribution of BCL-2 family members to their functions.
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Affiliation(s)
- Robert E Means
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Samuel G Katz
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
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2
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Mitochondrial targeting theranostic nanomedicine and molecular biomarkers for efficient cancer diagnosis and therapy. Biomed Pharmacother 2022; 153:113451. [DOI: 10.1016/j.biopha.2022.113451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/12/2022] [Accepted: 07/18/2022] [Indexed: 01/10/2023] Open
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3
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VDAC2 and the BCL-2 family of proteins. Biochem Soc Trans 2021; 49:2787-2795. [PMID: 34913469 PMCID: PMC8786305 DOI: 10.1042/bst20210753] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/21/2021] [Accepted: 11/26/2021] [Indexed: 12/26/2022]
Abstract
The BCL-2 protein family govern whether a cell dies or survives by controlling mitochondrial apoptosis. As dysregulation of mitochondrial apoptosis is a common feature of cancer cells, targeting protein–protein interactions within the BCL-2 protein family is a key strategy to seize control of apoptosis and provide favourable outcomes for cancer patients. Non-BCL-2 family proteins are emerging as novel regulators of apoptosis and are potential drug targets. Voltage dependent anion channel 2 (VDAC2) can regulate apoptosis. However, it is unclear how this occurs at the molecular level, with conflicting evidence in the literature for its role in regulating the BCL-2 effector proteins, BAK and BAX. Notably, VDAC2 is required for efficient BAX-mediated apoptosis, but conversely inhibits BAK-mediated apoptosis. This review focuses on the role of VDAC2 in apoptosis, discussing the current knowledge of the interaction between VDAC2 and BCL-2 family proteins and the recent development of an apoptosis inhibitor that targets the VDAC2–BAK interaction.
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Sioud F, Amor S, Toumia IB, Lahmar A, Aires V, Chekir-Ghedira L, Delmas D. A New Highlight of Ephedra alata Decne Properties as Potential Adjuvant in Combination with Cisplatin to Induce Cell Death of 4T1 Breast Cancer Cells In Vitro and In Vivo. Cells 2020; 9:E362. [PMID: 32033130 PMCID: PMC7072491 DOI: 10.3390/cells9020362] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/24/2020] [Accepted: 01/28/2020] [Indexed: 12/29/2022] Open
Abstract
Despite major advances in the last 10 years, whether in terms of prevention or treatment, the 5 year survival rate remains relatively low for a large number of cancers. These therapeutic failures can be the consequence of several factors associated with the cellular modifications or with the host by itself, especially for some anticancer drugs such as cisplatin, which induces a nephrotoxicity. In the strategy of research for active molecules capable both of exerting a protective action against the deleterious effects of cisplatin and exerting a chemosensitizing action with regard to cancer cells, we tested the potential effects of Ephedra alata Decne extract (E.A.) rich in polyphenolic compounds towards a 4T1 breast cancer model in vitro and in vivo. We showed that E.A. extract inhibited cell viability of 4T1 breast cancer cells and induced apoptosis in a caspase-dependent manner, which involved intrinsic pathways. Very interestingly, we observed a synergic antiproliferative and pro-apoptotic action with cisplatin. These events were associated with a strong decrease of breast tumor growth in mice treated with an E.A./cisplatin combination and simultaneously with a decrease of hepato- and nephrotoxicities of cisplatin.
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Affiliation(s)
- Fairouz Sioud
- Research Unit Bioactive Natural Products and Biotechnology UR17ES49, Faculty of Dental Medicine of Monastir, University of Monastir, Avicenne street, Monastir 5000, Tunisia; (F.S.); (I.b.T.); (A.L.); (L.C.-G.)
- Université de Bourgogne Franche-Comté, F-21000 Dijon, France; (S.A.); (V.A.)
- INSERM Research Center U1231—Cancer and Adaptive Immune Response Team, F-21000 Dijon, France
| | - Souheila Amor
- Université de Bourgogne Franche-Comté, F-21000 Dijon, France; (S.A.); (V.A.)
- INSERM Research Center U1231—Cancer and Adaptive Immune Response Team, F-21000 Dijon, France
| | - Imène ben Toumia
- Research Unit Bioactive Natural Products and Biotechnology UR17ES49, Faculty of Dental Medicine of Monastir, University of Monastir, Avicenne street, Monastir 5000, Tunisia; (F.S.); (I.b.T.); (A.L.); (L.C.-G.)
| | - Aida Lahmar
- Research Unit Bioactive Natural Products and Biotechnology UR17ES49, Faculty of Dental Medicine of Monastir, University of Monastir, Avicenne street, Monastir 5000, Tunisia; (F.S.); (I.b.T.); (A.L.); (L.C.-G.)
| | - Virginie Aires
- Université de Bourgogne Franche-Comté, F-21000 Dijon, France; (S.A.); (V.A.)
- INSERM Research Center U1231—Cancer and Adaptive Immune Response Team, F-21000 Dijon, France
| | - Leila Chekir-Ghedira
- Research Unit Bioactive Natural Products and Biotechnology UR17ES49, Faculty of Dental Medicine of Monastir, University of Monastir, Avicenne street, Monastir 5000, Tunisia; (F.S.); (I.b.T.); (A.L.); (L.C.-G.)
| | - Dominique Delmas
- Université de Bourgogne Franche-Comté, F-21000 Dijon, France; (S.A.); (V.A.)
- INSERM Research Center U1231—Cancer and Adaptive Immune Response Team, F-21000 Dijon, France
- Centre anticancéreux Georges François Leclerc Center, F-21000 Dijon, France
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Loss of Peter Pan (PPAN) Affects Mitochondrial Homeostasis and Autophagic Flux. Cells 2019; 8:cells8080894. [PMID: 31416196 PMCID: PMC6721654 DOI: 10.3390/cells8080894] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/30/2019] [Accepted: 08/10/2019] [Indexed: 12/11/2022] Open
Abstract
Nucleolar stress is a cellular response to inhibition of ribosome biogenesis or nucleolar disruption leading to cell cycle arrest and/or apoptosis. Emerging evidence points to a tight connection between nucleolar stress and autophagy as a mechanism underlying various diseases such as neurodegeneration and treatment of cancer. Peter Pan (PPAN) functions as a key regulator of ribosome biogenesis. We previously showed that human PPAN localizes to nucleoli and mitochondria and that PPAN knockdown triggers a p53-independent nucleolar stress response culminating in mitochondrial apoptosis. Here, we demonstrate a novel role of PPAN in the regulation of mitochondrial homeostasis and autophagy. Our present study characterizes PPAN as a factor required for maintaining mitochondrial integrity and respiration-coupled ATP production. PPAN interacts with cardiolipin, a lipid of the inner mitochondrial membrane. Down-regulation of PPAN enhances autophagic flux in cancer cells. PPAN knockdown promotes recruitment of the E3-ubiquitin ligase Parkin to damaged mitochondria. Moreover, we provide evidence that PPAN knockdown decreases mitochondrial mass in Parkin-expressing cells. In summary, our study uncovers that PPAN knockdown is linked to mitochondrial damage and stimulates autophagy.
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Vasquez-Montes V, Vargas-Uribe M, Pandey NK, Rodnin MV, Langen R, Ladokhin AS. Lipid-modulation of membrane insertion and refolding of the apoptotic inhibitor Bcl-xL. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1867:691-700. [PMID: 31004798 DOI: 10.1016/j.bbapap.2019.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 04/16/2019] [Indexed: 02/07/2023]
Abstract
Bcl-xL is a member of the Bcl-2 family of apoptotic regulators, responsible for inhibiting the permeabilization of the mitochondrial outer membrane, and a promising anti-cancer target. Bcl-xL exists in the following conformations, each believed to play a role in the inhibition of apoptosis: (a) a soluble folded conformation, (b) a membrane-anchored (by its C-terminal α8 helix) form, which retains the same fold as in solution and (c) refolded membrane-inserted conformations, for which no structural data are available. Previous studies established that in the cell Bcl-xL exists in a dynamic equilibrium between soluble and membranous states, however, no direct evidence exists in support of either anchored or inserted conformation of the membranous state in vivo. In this in vitro study, we employed a combination of fluorescence and EPR spectroscopy to characterize structural features of the bilayer-inserted conformation of Bcl-xL and the lipid modulation of its membrane insertion transition. Our results indicate that the core hydrophobic helix α6 inserts into the bilayer without adopting a transmembrane orientation. This insertion disrupts the packing of Bcl-xL and releases the regulatory N-terminal BH4 domain (α1) from the rest of the protein structure. Our data demonstrate that both insertion and refolding of Bcl-xL are modulated by lipid composition, which brings the apparent pKa of insertion to the threshold of physiological pH. We hypothesize that conformational rearrangements associated with the bilayer insertion of Bcl-xL result in its switching to a so-called non-canonical mode of apoptotic inhibition. Presented results suggest that the alteration in lipid composition before and during apoptosis can serve as an additional factor regulating the permeabilization of the mitochondrial outer membrane.
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Affiliation(s)
- Victor Vasquez-Montes
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Mauricio Vargas-Uribe
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Nitin K Pandey
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, USA
| | - Mykola V Rodnin
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Ralf Langen
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, USA
| | - Alexey S Ladokhin
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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Oh JH, Jeong KH, Kim JE, Kang H. Synthesized Ceramide Induces Growth of Dermal Papilla Cells with Potential Contribution to Hair Growth. Ann Dermatol 2019; 31:164-174. [PMID: 33911565 PMCID: PMC7992683 DOI: 10.5021/ad.2019.31.2.164] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/16/2018] [Accepted: 10/23/2018] [Indexed: 11/21/2022] Open
Abstract
Background The ceramide is known to play an important role in the formation of intracellular lipids, and play a crucial role as a barrier for skin and hair cuticle. Recent study has revealed that ceramide has potential effect on hair growth in a mouse model. However, the role of ceramide in human dermal papilla cells (hDPCs) known to play an important role in hair growth is not well understood yet. Objective The goal of this study was to investigate the effect of synthetic ceramides (oleyl and stearyl ceramides) on hair growth using hDPCs. Methods hDPCs were treated with synthesized ceramides. hDPCs viability was evaluated by MTT assay. The expression of hair growth related factors were investigated by western blot, real-time polymerase chain reaction and growth factor array. The expression of β-catenin was confirmed by immunofluorescence. Results Treatment with ceramides increased the expression of proteins affecting cell proliferation such as Bcl-2, BAX, phosphorylated-ERK and Cyclin D1. Also, ceramides treatment were increased the expression of several growth factors, including epidermal growth factor family, and promote the expression of Wnt/β-catenin and BMP2/4 signaling. Conclusion Our data suggest that synthetic ceramides stimulates hair growth by induction proliferation of hDPCs via modulation of Wnt/β-catenin and BMP2/4 signaling.
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Affiliation(s)
- Jee Hye Oh
- Department of Dermatology, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Kwan Ho Jeong
- Department of Dermatology, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Jung Eun Kim
- Department of Dermatology, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hoon Kang
- Department of Dermatology, St. Paul's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
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Ugarte-Uribe B, García-Sáez AJ. Apoptotic foci at mitochondria: in and around Bax pores. Philos Trans R Soc Lond B Biol Sci 2018. [PMID: 28630156 DOI: 10.1098/rstb.2016.0217] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The permeabilization of the mitochondrial outer membrane by Bax and Bak during apoptosis is considered a key step and a point of no return in the signalling pathway. It is always closely related to the reorganization of mitochondrial cristae that frees cytochrome c to the intermembrane space and to massive mitochondrial fragmentation mediated by the dynamin-like protein Drp1. Despite multiple evidence in favour of a functional link between these processes, the molecular mechanisms that connect them and their relevance for efficient apoptosis signalling remain obscure. In this review, we discuss recent progress on our understanding of how Bax forms pores in the context of Drp1-stabilized signalling platforms at apoptotic foci in mitochondria.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.
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Affiliation(s)
- Begoña Ugarte-Uribe
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe Seyler Straße 4, 72076 Tübingen, Germany.,Biofisika Institute (UPV/EHU, CSIC), Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Ana J García-Sáez
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe Seyler Straße 4, 72076 Tübingen, Germany .,Max Planck Institute for Intelligent Systems, Stuttgart, Germany
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Peña‐Blanco A, García‐Sáez AJ. Bax, Bak and beyond — mitochondrial performance in apoptosis. FEBS J 2017; 285:416-431. [DOI: 10.1111/febs.14186] [Citation(s) in RCA: 340] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/12/2017] [Accepted: 07/26/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Aida Peña‐Blanco
- Interfaculty Institute of Biochemistry Tübingen University Germany
| | - Ana J. García‐Sáez
- Interfaculty Institute of Biochemistry Tübingen University Germany
- Max‐Planck Institute for Intelligent Systems Stuttgart Germany
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Lan T, Zhao H, Xiang B, Wang J, Liu Y. Suture compression induced midpalatal suture chondrocyte apoptosis with increased caspase-3, caspase-9, Bad, Bak, Bax and Bid expression. Biochem Biophys Res Commun 2017; 489:179-186. [DOI: 10.1016/j.bbrc.2017.05.120] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 05/22/2017] [Indexed: 10/19/2022]
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Go KL, Lee S, Behrns KE, Kim JS. Mitochondrial Damage and Mitophagy in Ischemia/Reperfusion-Induced Liver Injury. MOLECULES, SYSTEMS AND SIGNALING IN LIVER INJURY 2017:183-219. [DOI: 10.1007/978-3-319-58106-4_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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12
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Pointer CB, Klegeris A. Cardiolipin in Central Nervous System Physiology and Pathology. Cell Mol Neurobiol 2016; 37:1161-1172. [PMID: 28039536 DOI: 10.1007/s10571-016-0458-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 12/19/2016] [Indexed: 02/08/2023]
Abstract
Cardiolipin, an anionic phospholipid found primarily in the inner mitochondrial membrane, has many well-defined roles within the peripheral tissues, including the maintenance of mitochondrial membrane fluidity and the regulation of mitochondrial functions. Within the central nervous system (CNS), cardiolipin is found within both neuronal and non-neuronal glial cells, where it regulates metabolic processes, supports mitochondrial functions, and promotes brain cell viability. Furthermore, cardiolipin has been shown to act as an elimination signal and participate in programmed cell death by apoptosis of both neurons and glia. Since cardiolipin is associated with regulating brain homeostasis, the modification of its structure, or even a decrease in the overall levels of cardiolipin, can result in mitochondrial dysfunction, which is a characteristic feature of many diseases. In this review, we outline the various functions of cardiolipin within the cells of the CNS, including neurons, astrocytes, microglia, and oligodendrocytes. In addition, we discuss the role cardiolipin may play in the pathogenesis of the neurodegenerative disorders Alzheimer's disease and Parkinson's disease, as well as traumatic brain injury.
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Affiliation(s)
- Caitlin B Pointer
- Department of Biology, University of British Columbia, Okanagan Campus, Kelowna, BC, V1V 1V7, Canada
| | - Andis Klegeris
- Department of Biology, University of British Columbia, Okanagan Campus, Kelowna, BC, V1V 1V7, Canada.
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Flores-Toro JA, Go KL, Leeuwenburgh C, Kim JS. Autophagy in the liver: cell's cannibalism and beyond. Arch Pharm Res 2016; 39:1050-61. [PMID: 27515049 DOI: 10.1007/s12272-016-0807-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 08/02/2016] [Indexed: 02/06/2023]
Abstract
Chronic liver disease and its progression to liver failure are induced by various etiologies including viral infection, alcoholic and nonalcoholic hepatosteatosis. It is anticipated that the prevalence of fatty liver disease will continue to rise due to the growing incidence of obesity and metabolic disorder. Evidence is accumulating to indicate that the onset of fatty liver disease is causatively linked to mitochondrial dysfunction and abnormal lipid accumulation. Current treatment options for this disease are limited. Autophagy is an integral catabolic pathway that maintains cellular homeostasis both selectively and nonselectively. As mitophagy and lipophagy selectively remove dysfunctional mitochondria and excess lipids, respectively, stimulation of autophagy could have therapeutic potential to ameliorate liver function in steatotic patients. This review highlights our up-to-date knowledge on mechanistic roles of autophagy in the pathogenesis of fatty liver disease and its vulnerability to surgical stress, with an emphasis on mitophagy and lipophagy.
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Affiliation(s)
- Joseph A Flores-Toro
- Department of Surgery, University of Florida, R4-204 ARB, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Kristina L Go
- Department of Surgery, University of Florida, R4-204 ARB, 1600 SW Archer Rd, Gainesville, FL, 32610, USA
| | - Christiaan Leeuwenburgh
- Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, 32610, USA
- Institute on Aging, University of Florida, Gainesville, FL, 32610, USA
| | - Jae-Sung Kim
- Department of Surgery, University of Florida, R4-204 ARB, 1600 SW Archer Rd, Gainesville, FL, 32610, USA.
- Institute on Aging, University of Florida, Gainesville, FL, 32610, USA.
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Luna-Vargas MP, Chipuk JE. The deadly landscape of pro-apoptotic BCL-2 proteins in the outer mitochondrial membrane. FEBS J 2016; 283:2676-89. [PMID: 26662859 PMCID: PMC4907887 DOI: 10.1111/febs.13624] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 11/11/2015] [Accepted: 12/08/2015] [Indexed: 01/06/2023]
Abstract
Apoptosis is a biological process that removes damaged, excess or infected cells through a genetically controlled mechanism. This process plays a crucial role in organismal development, immunity and tissue homeostasis, and alterations in apoptosis contribute to human diseases including cancer and auto-immunity. In the past two decades, significant efforts have focused on understanding the function of the BCL-2 proteins, a complex family of pro-survival and pro-apoptotic α-helical proteins that directly control the mitochondrial pathway of apoptosis. Diverse structural investigations of the BCL-2 family members have broadened our mechanistic understanding of their individual functions. However, an often over-looked aspect of the mitochondrial pathway of apoptosis is how the BCL-2 family specifically interacts with and targets the outer mitochondrial membrane to initiate apoptosis. Structural information on the relationship between the BCL-2 family and the outer mitochondrial membrane is missing; likewise, knowledge of the biophysical mechanisms by which the outer mitochondrial membrane affects and effects apoptosis is lacking. In this mini-review, we provide a current overview of the BCL-2 family members and discuss the latest structural insights into BAK/BAX activation and oligomerization in the context of the outer mitochondrial membrane and mitochondrial biology.
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Affiliation(s)
- Mark P.A. Luna-Vargas
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Jerry E. Chipuk
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
- The Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
- Department of Dermatology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
- The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
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Cardiolipin or MTCH2 can serve as tBID receptors during apoptosis. Cell Death Differ 2016; 23:1165-74. [PMID: 26794447 DOI: 10.1038/cdd.2015.166] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 09/22/2015] [Accepted: 11/26/2015] [Indexed: 01/07/2023] Open
Abstract
During apoptosis, proapoptotic BAX and BAK trigger mitochondrial outer membrane (MOM) permeabilization by a mechanism that is not yet fully understood. BH3-only proteins such as tBID, together with lipids of the MOM, are thought to play a key role in BAX and BAK activation. In particular, cardiolipin (CL) has been shown to stimulate tBID-induced BAX activation in vitro. However, it is still unclear whether this process also relies on CL in the cell, or whether it is more dependent on MTCH2, a proposed receptor for tBID present in the MOM. To address this issue, we deleted both alleles of cardiolipin synthase in human HCT116 cells by homologous recombination, which resulted in a complete absence of CL. The CL-deficient cells were fully viable in glucose but displayed impaired oxidative phosphorylation and an inability to grow in galactose. Using these cells, we found that CL was not required for either tBID-induced BAX activation, or for apoptosis in response to treatment with TRAIL. Downregulation of MTCH2 in HCT116 cells also failed to prevent recruitment of tBID to mitochondria in apoptotic conditions. However, when both CL and MTCH2 were depleted, a significant reduction in tBID recruitment was observed, suggesting that in HCT116 cells, CL and MTCH2 can have redundant functions in this process.
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Lin JT, Chang YY, Chen YC, Hu CC, Chang YP, Hsu SH, Yang DJ. Induction of apoptotic death of human hepatocellular carcinoma (HepG2) cells by ethanolic extract from litchi (Litchi chinensis Sonn.) flower. J Funct Foods 2015. [DOI: 10.1016/j.jff.2015.08.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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The Role of Cardiolipin in Cardiovascular Health. BIOMED RESEARCH INTERNATIONAL 2015; 2015:891707. [PMID: 26301254 PMCID: PMC4537736 DOI: 10.1155/2015/891707] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/08/2015] [Indexed: 12/20/2022]
Abstract
Cardiolipin (CL), the signature phospholipid of mitochondrial membranes, is crucial for both mitochondrial function and cellular processes outside of the mitochondria. The importance of CL in cardiovascular health is underscored by the life-threatening genetic disorder Barth syndrome (BTHS), which manifests clinically as cardiomyopathy, skeletal myopathy, neutropenia, and growth retardation. BTHS is caused by mutations in the gene encoding tafazzin, the transacylase that carries out the second CL remodeling step. In addition to BTHS, CL is linked to other cardiovascular diseases (CVDs), including cardiomyopathy, atherosclerosis, myocardial ischemia-reperfusion injury, heart failure, and Tangier disease. The link between CL and CVD may possibly be explained by the physiological roles of CL in pathways that are cardioprotective, including mitochondrial bioenergetics, autophagy/mitophagy, and mitogen activated protein kinase (MAPK) pathways. In this review, we focus on the role of CL in the pathogenesis of CVD as well as the molecular mechanisms that may link CL functions to cardiovascular health.
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Liu B, Bhatt D, Oltvai ZN, Greenberger JS, Bahar I. Significance of p53 dynamics in regulating apoptosis in response to ionizing radiation, and polypharmacological strategies. Sci Rep 2014; 4:6245. [PMID: 25175563 PMCID: PMC4150106 DOI: 10.1038/srep06245] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 08/11/2014] [Indexed: 01/22/2023] Open
Abstract
Developing pharmacological strategies for controlling ionizing radiation (IR)-induced cell death is important for both mitigating radiation damage and alleviating the side effects of anti-cancer radiotherapy manifested in surrounding tissue morbidity. Exposure to IR often triggers the onset of p53-dependent apoptotic pathways. Here we build a stochastic model of p53 induced apoptosis comprised of coupled modules of nuclear p53 activation, mitochondrial cytochrome c release and cytosolic caspase activation that also takes into account cellular heterogeneity. Our simulations show that the strength of p53 transcriptional activity and its coupling (or timing with respect) to mitochondrial pore opening are major determinants of cell fate: for systems where apoptosis is elicited via a p53-transcription-independent mechanism, direct activation of Bax by p53 becomes critical to IR-induced-damage initiation. We further show that immediate administration of PUMA inhibitors following IR exposure effectively suppresses excessive cell death, provided that there is a strong caspase/Bid feedback loop; however, the efficacy of the treatment diminishes with increasing delay in treatment implementation. In contrast, the combined inhibition of Bid and Bax elicits an anti-apoptotic response that is effective over a range of time delays.
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Affiliation(s)
- Bing Liu
- 1] Department of Computational &Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA [2]
| | - Divesh Bhatt
- 1] Department of Computational &Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA [2]
| | - Zoltán N Oltvai
- 1] Department of Computational &Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA [2] Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joel S Greenberger
- Department of Radiation Oncology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ivet Bahar
- Department of Computational &Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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19
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Chi X, Kale J, Leber B, Andrews DW. Regulating cell death at, on, and in membranes. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1843:2100-13. [PMID: 24927885 DOI: 10.1016/j.bbamcr.2014.06.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 05/29/2014] [Accepted: 06/03/2014] [Indexed: 11/17/2022]
Abstract
Bcl-2 family proteins are central regulators of apoptosis. Various family members are located in the cytoplasm, endoplasmic reticulum, and mitochondrial outer membrane in healthy cells. However during apoptosis most of the interactions between family members that determine the fate of the cell occur at the membranes of intracellular organelles. It has become evident that interactions with membranes play an active role in the regulation of Bcl-2 family protein interactions. Here we provide an overview of various models proposed to explain how the Bcl-2 family regulates apoptosis and discuss how membrane binding affects the structure and function of each of the three categories of Bcl-2 proteins (pro-apoptotic, pore-forming, and anti-apoptotic). We also examine how the Bcl-2 family regulates other aspects of mitochondrial and ER physiology relevant to cell death.
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Affiliation(s)
- Xiaoke Chi
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Justin Kale
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - Brian Leber
- Department of Medicine, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
| | - David W Andrews
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8N 3Z5, Canada; Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada; Biological Sciences, Sunnybrook Research Institute, Toronto, Ontario M4N 3M5, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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20
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Deguchi J, Horiguchi K, Wong CP, Hosoya T, Iihoshi A, Kaneda T, Morita H. Sucutinirane-diterpene derivatives induce apoptosis via oxidative stress in HL-60 cells. J Nat Med 2014; 68:723-9. [DOI: 10.1007/s11418-014-0848-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/16/2014] [Indexed: 12/25/2022]
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21
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Paradies G, Paradies V, Ruggiero FM, Petrosillo G. Cardiolipin and mitochondrial function in health and disease. Antioxid Redox Signal 2014; 20:1925-53. [PMID: 24094094 DOI: 10.1089/ars.2013.5280] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cardiolipin (CL) is a unique phospholipid that is almost exclusively localized at the level of the inner mitochondrial membrane (IMM), where it is biosynthesized. This phospholipid is associated with membranes which are designed to generate an electrochemical gradient that is used to produce ATP. Such membranes include the bacterial plasma membrane and IMM. This ubiquitous and intimate association between CL and energy-transducing membranes suggests an important role for CL in mitochondrial bioenergetic processes. CL has been shown to interact with a number of IMM proteins, including the respiratory chain complexes and substrate carriers. Moreover, CL is involved in different stages of the mitochondrial apoptosis process as well as in mitochondrial membrane stability and dynamics. Alterations in CL structure, content, and acyl chain composition have been associated with mitochondrial dysfunction in multiple tissues in several physiopathological conditions and aging. In this review, we provide an overview of the roles of CL in mitochondrial function and bioenergetics in health and disease.
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Affiliation(s)
- Giuseppe Paradies
- 1 Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari , Bari, Italy
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22
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Cosentino K, García-Sáez AJ. Mitochondrial alterations in apoptosis. Chem Phys Lipids 2014; 181:62-75. [PMID: 24732580 DOI: 10.1016/j.chemphyslip.2014.04.001] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/20/2014] [Accepted: 04/02/2014] [Indexed: 12/31/2022]
Abstract
Besides their conventional role as energy suppliers for the cell, mitochondria in vertebrates are active regulators of apoptosis. They release apoptotic factors from the intermembrane space into the cytosol through a mechanism that involves the Bcl-2 protein family, mediating permeabilization of the outer mitochondrial membrane. Associated with this event, a number of additional changes affect mitochondria during apoptosis. They include loss of important mitochondrial functions, such as the ability to maintain calcium homeostasis and to generate ATP, as well as mitochondrial fragmentation and cristae remodeling. Moreover, the lipidic component of mitochondrial membranes undergoes important alterations in composition and distribution, which have turned out to be relevant regulatory events for the proteins involved in apoptotic mitochondrial damage.
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Affiliation(s)
- Katia Cosentino
- German Cancer Research Center, Heidelberg, Germany; Max-Planck Institute for Intelligent Systems, Stuttgart, Germany
| | - Ana J García-Sáez
- German Cancer Research Center, Heidelberg, Germany; Max-Planck Institute for Intelligent Systems, Stuttgart, Germany; Interfaculty Institute of Biochemistry (IFIB), University of Tübingen, Tübingen, Germany.
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23
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Raemy E, Martinou JC. Involvement of cardiolipin in tBID-induced activation of BAX during apoptosis. Chem Phys Lipids 2014; 179:70-4. [DOI: 10.1016/j.chemphyslip.2013.12.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 12/02/2013] [Accepted: 12/04/2013] [Indexed: 02/08/2023]
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24
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Liu L, Yim H, Choi JH, Kim ST, Jin Y, Lee SK. ATM kinase promotes both caspase-8 and caspase-9 activation during TNF-α-induced apoptosis of HeLa cells. FEBS Lett 2014; 588:929-35. [PMID: 24530529 DOI: 10.1016/j.febslet.2014.01.050] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 12/31/2013] [Accepted: 01/04/2014] [Indexed: 11/24/2022]
Abstract
In this study, we show that atraxia telangiectasia mutated kinase (ATM) activity is generally upregulated by different apoptotic stimuli, i.e. TNF-α, TRAIL, paclitaxel, or UV. Apoptotic progression is markedly attenuated by siATM-RNA through down regulation of caspase-8 and caspase-9 in parallel with decreases in FLIP-S (short form of cellular FLICE inhibitory protein) protein levels and Bid cleavage. In addition, ATM activity is upregulated through t-Cdc6 while caspase-8 and caspase-9 activities increase. Taken together, we suggest that ATM regulates caspase-8 activation by influencing levels of FLIP-S, ATM kinase activity is upregulated by t-Cdc6, and increased ATM activity plays an essential role in the amplification of apoptosis in TNF-α-stimulated HeLa cells.
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Affiliation(s)
- Linhua Liu
- Department of Biochemistry, Institute of Glycobiology, Dalian Medical University, 9 South Lvshun Road Western Section, Dalian, 116044 Liaoning, China; Division of Pharmaceutical Biosciences, Research Institute for Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, South Korea.
| | - Hyungshin Yim
- Division of Pharmaceutical Biosciences, Research Institute for Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, South Korea; Department of Pharmacy, College of Pharmacy, Hanyang University, 55 Hanyangdaehak-ro, Sangrok-gu, Ansan, Kyeonggi-do 426-791, South Korea
| | - Jae Hyuk Choi
- Division of Pharmaceutical Biosciences, Research Institute for Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, South Korea
| | - Seung-Tak Kim
- Division of Pharmaceutical Biosciences, Research Institute for Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, South Korea
| | - Yinghua Jin
- Department of Life Science, Jilin University, Jiefang Road, Changchun, China
| | - Seung Ki Lee
- Division of Pharmaceutical Biosciences, Research Institute for Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, South Korea
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25
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Renault TT, Chipuk JE. Death upon a kiss: mitochondrial outer membrane composition and organelle communication govern sensitivity to BAK/BAX-dependent apoptosis. ACTA ACUST UNITED AC 2013; 21:114-23. [PMID: 24269152 DOI: 10.1016/j.chembiol.2013.10.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 10/03/2013] [Accepted: 10/21/2013] [Indexed: 01/24/2023]
Abstract
For stressed cells to induce the mitochondrial pathway of apoptosis, a cohort of pro-apoptotic BCL-2 proteins must collaborate with the outer mitochondrial membrane to permeabilize it. BAK and BAX are the two pro-apoptotic BCL-2 family members that are required for mitochondrial outer membrane permeabilization. While biochemical and structural insights of BAK/BAX function have expanded in recent years, very little is known about the role of the outer mitochondrial membrane in regulating BAK/BAX activity. In this review, we will highlight the impact of mitochondrial composition (both protein and lipid) and mitochondrial interactions with cellular organelles on BAK/BAX function and cellular commitment to apoptosis. A better understanding of how BAK/BAX and mitochondrial biology are mechanistically linked will likely reveal novel insights into homeostatic and pathological mechanisms associated with apoptosis.
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Affiliation(s)
- Thibaud T Renault
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA; Department of Dermatology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA; The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA; The Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA
| | - Jerry E Chipuk
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA; Department of Dermatology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA; The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA; The Metabolism Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA; The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1130, New York, NY 10029, USA.
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26
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Paradies G, Paradies V, De Benedictis V, Ruggiero FM, Petrosillo G. Functional role of cardiolipin in mitochondrial bioenergetics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:408-17. [PMID: 24183692 DOI: 10.1016/j.bbabio.2013.10.006] [Citation(s) in RCA: 345] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 10/17/2013] [Accepted: 10/22/2013] [Indexed: 12/16/2022]
Abstract
Cardiolipin is a unique phospholipid which is almost exclusively located in the inner mitochondrial membrane where it is biosynthesized. Considerable progress has recently been made in understanding the role of cardiolipin in mitochondrial function and bioenergetics. This phospholipid is associated with membranes designed to generate an electrochemical gradient that is used to produce ATP, such as bacterial plasma membranes and inner mitochondrial membrane. This ubiquitous and intimate association between cardiolipin and energy transducing membranes indicates an important role for cardiolipin in mitochondrial bioenergetic processes. Cardiolipin has been shown to interact with a number of proteins, including the respiratory chain complexes and substrate carrier proteins. Over the past decade, the significance of cardiolipin in the organization of components of the electron transport chain into higher order assemblies, termed respiratory supercomplexes, has been established. Moreover, cardiolipin is involved in different stages of the mitochondrial apoptotic process, as well as in mitochondrial membrane stability and dynamics. This review discusses the current understanding of the functional role that cardiolipin plays in several reactions and processes involved in mitochondrial bioenergetics. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
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Affiliation(s)
- Giuseppe Paradies
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy.
| | - Valeria Paradies
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Valentina De Benedictis
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Francesca M Ruggiero
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Giuseppe Petrosillo
- Institute of Biomembranes and Bioenergetics, National Research Council, Bari, Italy
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27
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Wang Y, Tjandra N. Structural insights of tBid, the caspase-8-activated Bid, and its BH3 domain. J Biol Chem 2013; 288:35840-51. [PMID: 24158446 DOI: 10.1074/jbc.m113.503680] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Bcl-2 family proteins regulate mitochondria-mediated apoptosis through intricate molecular mechanisms. One of the pro-apoptotic proteins, tBid, can induce apoptosis by promoting Bax activation, Bax homo-oligomerization, and mitochondrial outer membrane permeabilization. Association of tBid on the mitochondrial outer membrane is key to its biological function. Therefore knowing the conformation of tBid on the membrane will be the first step toward understanding its crucial role in triggering apoptosis. Here, we present NMR characterization of the structure and dynamics of human tBid in 1-palmitoyl-2-hydroxy-sn-glycero-3-[phospho-RAC-(1-glycerol)] micelles. Our data showed that tBid is monomeric with six well defined α-helices in the micelles. Compared with the full-length Bid structure, a longer flexible loop between tBid helix α4 and α5 was observed. Helices in tBid do not pack into a compact-fold but form an extended structure with a C-shape configuration in the micelles. All six tBid helices were shown to interact with LPPG micelles, with helix α6 and α7 being more embedded. Of note, the BH3-containing helix α3, which was previously believed to be exposed above the membrane surface, is also membrane associated, suggesting an "on the membrane" binding mode for tBid interaction with Bax. Our data provided structural details on the membrane-associated state of tBid and the functional implications of its membrane-associated BH3 domain.
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Affiliation(s)
- Yu Wang
- From the Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
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28
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Emerging roles of lipids in BCL-2 family-regulated apoptosis. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1542-54. [DOI: 10.1016/j.bbalip.2013.03.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 02/28/2013] [Accepted: 03/02/2013] [Indexed: 01/06/2023]
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Abstract
SIGNIFICANCE The intrinsic apoptosis pathway is conserved from worms to humans and plays a critical role in the normal development and homeostatic control of adult tissues. As a result, numerous diseases from cancer to neurodegeneration are associated with either too little or too much apoptosis. RECENT ADVANCES B cell lymphoma-2 (BCL-2) family members regulate cell death, primarily via their effects on mitochondria. In stressed cells, proapoptotic BCL-2 family members promote mitochondrial outer membrane permeabilization (MOMP) and cytochrome c (cyt c) release into the cytoplasm, where it stimulates formation of the "apoptosome." This large, multimeric complex is composed of the adapter protein, apoptotic protease-activating factor-1, and the cysteine protease, caspase-9. Recent studies suggest that proteins involved in the processes leading up to (and including) formation of the apoptosome are subject to various forms of post-translational modification, including proteolysis, phosphorylation, and in some cases, direct oxidative modification. CRITICAL ISSUES Despite intense investigation of the intrinsic pathway, significant questions remain regarding how cyt c is released from mitochondria, how the apoptosome is formed and regulated, and how caspase-9 is activated within the complex. FUTURE DIRECTIONS Further studies on the biochemistry of MOMP and apoptosome formation are needed to understand the mechanisms that underpin these critical processes, and novel animal models will be necessary in the future to ascertain the importance of the many posttranslational modifications reported for BCL-2 family members and components of the apoptosome.
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Affiliation(s)
- Chu-Chiao Wu
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA
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30
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Caspase-8 binding to cardiolipin in giant unilamellar vesicles provides a functional docking platform for bid. PLoS One 2013; 8:e55250. [PMID: 23418437 PMCID: PMC3572128 DOI: 10.1371/journal.pone.0055250] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 12/21/2012] [Indexed: 12/28/2022] Open
Abstract
Caspase-8 is involved in death receptor-mediated apoptosis in type II cells, the proapoptotic programme of which is triggered by truncated Bid. Indeed, caspase-8 and Bid are the known intermediates of this signalling pathway. Cardiolipin has been shown to provide an anchor and an essential activating platform for caspase-8 at the mitochondrial membrane surface. Destabilisation of this platform alters receptor-mediated apoptosis in diseases such as Barth Syndrome, which is characterised by the presence of immature cardiolipin which does not allow caspase-8 binding. We used a simplified in vitro system that mimics contact sites and/or cardiolipin-enriched microdomains at the outer mitochondrial surface in which the platform consisting of caspase-8, Bid and cardiolipin was reconstituted in giant unilamellar vesicles. We analysed these vesicles by flow cytometry and confirm previous results that demonstrate the requirement for intact mature cardiolipin for caspase-8 activation and Bid binding and cleavage. We also used confocal microscopy to visualise the rupture of the vesicles and their revesiculation at smaller sizes due to alteration of the curvature following caspase-8 and Bid binding. Biophysical approaches, including Laurdan fluorescence and rupture/tension measurements, were used to determine the ability of these three components (cardiolipin, caspase-8 and Bid) to fulfil the minimal requirements for the formation and function of the platform at the mitochondrial membrane. Our results shed light on the active functional role of cardiolipin, bridging the gap between death receptors and mitochondria.
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Patil VA, Greenberg ML. Cardiolipin-mediated cellular signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 991:195-213. [PMID: 23775697 DOI: 10.1007/978-94-007-6331-9_11] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
This review focuses on recent studies showing that cardiolipin (CL), a unique mitochondrial phospholipid, regulates many cellular functions and signaling pathways, both inside and outside the mitochondria. Inside the mitochondria, CL is a critical target of mitochondrial generated reactive oxygen species (ROS) and regulates signaling events related to apoptosis and aging. CL deficiency causes perturbation of signaling pathways outside the mitochondria, including the PKC-Slt2 cell integrity pathway and the high osmolarity glycerol (HOG) pathway, and is a key player in the cross-talk between the mitochondria and the vacuole. Understanding these connections may shed light on the pathology of Barth syndrome, a disorder of CL remodeling.
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Affiliation(s)
- Vinay A Patil
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
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32
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Bender T, Martinou JC. Where killers meet--permeabilization of the outer mitochondrial membrane during apoptosis. Cold Spring Harb Perspect Biol 2013; 5:a011106. [PMID: 23284044 DOI: 10.1101/cshperspect.a011106] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Although mitochondria are usually considered as supporters of life, they are also involved in cellular death. Mitochondrial outer membrane permeabilization (MOMP) is a crucial event during apoptosis because it causes the release of proapoptotic factors from the mitochondrial intermembrane space to the cytosol. MOMP is mainly controlled by the Bcl-2 family of proteins, which consists of both proapoptotic and antiapoptotic members. We discuss the current understanding of how activating and inhibitory interactions within this family lead to the activation and oligomerization of MOMP effectors Bax and Bak, which result in membrane permeabilization. The order of events leading to MOMP is then highlighted step by step, emphasizing recent discoveries regarding the formation of Bax/Bak pores on the outer mitochondrial membrane. Besides the Bcl-2 proteins, the mitochondrial organelle contributes to and possibly regulates MOMP, because mitochondrial resident proteins and membrane lipids are prominently involved in the process.
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Affiliation(s)
- Tom Bender
- Department of Cell Biology, University of Geneva, 1211 Geneva 4, Switzerland
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33
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De Paepe B. Mitochondrial Markers for Cancer: Relevance to Diagnosis, Therapy, and Prognosis and General Understanding of Malignant Disease Mechanisms. ACTA ACUST UNITED AC 2012. [DOI: 10.5402/2012/217162] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cancer cells display changes that aid them to escape from cell death, sustain their proliferative powers, and shift their metabolism toward glycolytic energy production. Mitochondria are key organelles in many metabolic and biosynthetic pathways, and the adaptation of mitochondrial function has been recognized as crucial to the changes that occur in cancer cells. This paper zooms in on the pathologic evaluation of mitochondrial markers for diagnosing and staging of human cancer and determining the patients’ prognoses.
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Affiliation(s)
- Boel De Paepe
- Laboratories for Neuropathology & Mitochondrial Disorders, Ghent University Hospital, Building K5 3rd Floor, De Pintelaan 185, 9000 Ghent, Belgium
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34
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The oxidized phospholipid PazePC modulates interactions between Bax and mitochondrial membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2718-24. [DOI: 10.1016/j.bbamem.2012.06.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 05/31/2012] [Accepted: 06/05/2012] [Indexed: 01/01/2023]
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Shimoji M, Imaizumi N, Aniya Y. Modulation of membrane-bound glutathione transferase activity by phospholipids including cardiolipin. Biol Pharm Bull 2011; 34:209-13. [PMID: 21415529 DOI: 10.1248/bpb.34.209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Membrane-bound glutathione transferases (MGST1) distributed mostly in liver microsomal and mitochondrial membranes are activated by the thiol modification. In the present study, the effect of phospholipids on MGST1 activity was investigated using purified enzyme. When MGST1 was mixed with liposomes of cardiolipin (CL), phosphatidylcholine (PC), phosphatidylserine (PC), or phosphatidylethanolamine (PE), its activity was increased in a magnitude which was dependent on the anionic property of lipids in the order of CL>PS>PE>PC, indicating that MGST1 activity is enhanced by surrounding anionic lipids. Although MGST1 was activated by the thiol alkylation with N-ethylmaleimide (NEM), the activation was suppressed in the presence of anionic phospholipids as clearly observed in the presence of CL. Similarly, the activation of MGST1 by diamide or diamide plus glutathione through disulfide-bond formation was also disturbed in the presence of CL. Suppression of NEM-derived MGST1 activation by CL was lost when MGST1 was incubated with CL in the presence of the detergent Triton X-100. These results indicate that reactivity (stability) of the thiol in MGST1 is affected by surrounding lipids, namely CL which prevents MGST1 activation by thiol modification. Since CL is a mitochondria specific lipid located in the inner membrane, it was suggested that function of mitochondrial MGST1 could be regulated by interaction with CL.
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Affiliation(s)
- Mayumi Shimoji
- Laboratory of Molecular Genetics and Pharmacology, School of Health Sciences, Faculty of Medicine, University of the Ryukyus
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36
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Singaravelu K, Padanilam BJ. p53 target Siva regulates apoptosis in ischemic kidneys. Am J Physiol Renal Physiol 2011; 300:F1130-41. [PMID: 21307125 PMCID: PMC3094050 DOI: 10.1152/ajprenal.00591.2010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Accepted: 02/04/2011] [Indexed: 01/07/2023] Open
Abstract
The role of p53 in inducing apoptosis following acute kidney injury is well-established; however, the molecular mechanisms remain largely unknown. We report here that the p53 proapoptotic target Siva and its receptor CD27, a member of the tumor necrosis factor receptor family, are upregulated following renal ischemia-reperfusion injury (IRI). Inhibition of Siva using antisense oligonucleotides conferred functional and morphological protection, and it prevented apoptosis postrenal IRI in mice. Renal IRI in CD27-deficient mice displayed functional protection and partial inhibition of apoptosis, suggesting an incomplete role for CD27 in Siva-mediated apoptosis. To further elucidate mechanisms by which Siva elicits apoptosis, in vitro studies were performed. In Siva-transfected LLC-PK(1)cells, Siva is persistently expressed in the nucleus at 3 h onwards and its translocation to mitochondria and the plasma membrane occurred at 6 h. Moreover, Siva overexpression induced mitochondrial permeability, cytochrome c release, caspase-8 and -9 activation, translocation of apoptosis-inducing factor (AIF) to the nucleus, and apoptosis. Inhibition of Siva in ischemic kidneys prevented mitochondrial release of cytochrome c and AIF. These data indicate that Siva function is pivotal in regulating apoptosis in the pathology of renal IRI. Targeting Siva may offer a potential therapeutic strategy for renal IRI.
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Affiliation(s)
- Kurinji Singaravelu
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, 68198-5850, USA
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Martínez-Abundis E, Correa F, Rodríguez E, Soria-Castro E, Rodríguez-Zavala JS, Pacheco-Alvarez D, Zazueta C. A CRAC-like motif in BAX sequence: relationship with protein insertion and pore activity in liposomes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1888-95. [PMID: 21440528 DOI: 10.1016/j.bbamem.2011.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 01/26/2011] [Accepted: 03/21/2011] [Indexed: 02/08/2023]
Abstract
Several proteins that interact with cholesterol have a highly conserved sequence, corresponding to the cholesterol recognition/interaction amino acid consensus. Since cholesterol has been proposed to modulate both oligomerization and insertion of the pro-apoptotic protein BAX, we investigated the existence of such a motif in the BAX sequence. Residues 113 to 119 of the recombinant BAX α5-helix, LFYFASK, correspond with the sequence motif described for the consensus pattern, -L/V-(X)(1-5)-Y-(X)(1-5)-R/K. Functional characterization of the point mutations, K119A, Y115F, and L113A in BAX, was performed in liposomes supplemented with cholesterol, comparing binding, integration, and pore forming activities. Our results show that the mutations Y115F and L113A changed the cholesterol-dependent insertion observed in the wild type protein. In addition, substitutions in the BAX sequence modified the concentration dependency of carboxyfluorescein release in liposomes, although neither pore activity of the wild type or of any of the mutants significantly increased in cholesterol-enriched liposomes. Thus, while it is likely that the putative CRAC motif in BAX accounts for its enhanced insertion in cholesterol-enriched liposomes; the pore forming properties of BAX did not depend on cholesterol content in the membranes, albeit those mutations changed the pore channeling activity of the protein.
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Chang WJ, Chehab M, Kink S, Toledo-Pereyra LH. Intracellular calcium signaling pathways during liver ischemia and reperfusion. J INVEST SURG 2010; 23:228-38. [PMID: 20690849 DOI: 10.3109/08941939.2010.496036] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Calcium plays a major role in intracellular signaling mechanisms during ischemia reperfusion (I/R) injury of a liver cell. Under ischemic conditions, the absence of oxygen arrests oxidative phosphorylation, thereby eliminating the energy source by which hepatocellular mechanisms maintain homeostasis of calcium. This, in turn, leaves nonselective plasma membrane influx pores unopposed and results in a net increase in intracellular calcium concentrations. Subsequent reperfusion marks the onset and progression of apoptosis and necrosis, as it involves inflammatory responses as well as free-radical formation due to re-oxygenation of cells. These processes destroy the structural integrity of organelles, leading to disruptive redistribution of calcium between cellular and subcellular compartments. This initial elevation and later imbalance of intracellular calcium concentrations associated with I/R induce various molecular responses within each organelle. In the cytoplasm, a series of pro-apoptotic pathways involving various calcium sensitive enzymes are activated. The injury is further exacerbated in the endoplasmic reticulum (ER) due to the malfunction of mechanisms responsible for intracellular calcium sequestration. Both the mitochondria and the nucleus are also adversely affected, as their structural integrity and physiologic functions are disrupted. To date, however, the precise pathophysiology of these calcium-mediated signaling pathways is not fully understood due to its complex nature. This review aims to systematically examine the current literature about individual molecular signaling pathways in the cytoplasm, ER, mitochondria, and the nucleus prior to causing time-sensitive progression of permanent tissue injury.
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Affiliation(s)
- Wilson J Chang
- Kalamazoo Center for Medical Studies, Michigan State University, Kalamazoo, Michigan, USA
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Giant unilamellar vesicles (GUVs) as a new tool for analysis of caspase-8/Bid-FL complex binding to cardiolipin and its functional activity. Cell Death Dis 2010; 1:e103. [PMID: 21368876 PMCID: PMC3032292 DOI: 10.1038/cddis.2010.81] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Cardiolipin (CL) has recently been shown to be both an anchor and an essential activating platform for caspase-8 on mitochondria. These platforms may be at the mitochondrial contact sites in which truncated Bid (tBid) has been demonstrated to be located. A possible role for CL is to anchor caspase-8 at contact sites (between inner and outer membranes), facilitating its self-activation, Bid-full length (FL) cleavage, tBid generation (and Bax/Bak activation and oligomerization), mitochondrial destabilization and apoptosis. We have developed an in vitro system that mimics the mitochondrial membrane contact site platform. This system involves reconstituting caspase-8, Bid-FL and CL complexes in giant unilamellar vesicles (GUVs). We first validated the system by flow cytometry analysis of light-scattering properties and nonyl acridine orange staining of their CL content. Then, we used flow cytometry analysis to detect the binding of active caspase-8 to CL and the subsequent truncation of bound Bid-FL. The tBid generated interacts with CL and induces GUV breakage and partial re-vesiculation at a smaller size. Our findings suggest an active role for mitochondrial membrane lipids, particularly CL, in binding active caspase-8 and providing a docking site for Bid-FL. This phenomenon was previously only poorly documented and substantially underestimated.
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Heit B, Yeung T, Grinstein S. Changes in mitochondrial surface charge mediate recruitment of signaling molecules during apoptosis. Am J Physiol Cell Physiol 2010; 300:C33-41. [PMID: 20926778 DOI: 10.1152/ajpcell.00139.2010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Electrostatic interactions with negative lipids contribute to the subcellular localization of polycationic proteins. In situ measurements using cytosolic probes of surface charge indicate that normal mitochondria are not noticeably electronegative. However, during apoptosis mitochondria accrue negative charge and acquire the ability to attract cationic proteins, including K-Ras. The marked increase in the surface charge of mitochondria occurs early in apoptosis, preceding depolarization of their inner membrane, cytochrome c release, and flipping of phosphatidylserine across the plasmalemma. Using novel biosensors, we determined that the increased electronegativity of the mitochondria coincided with and was likely attributable to increased exposure of cardiolipin, which is dianionic. Ectopic (over)expression of cardiolipin-binding proteins precluded the increase in surface charge and inhibited apoptosis, implying that mitochondrial exposure of negatively charged lipids is required for progression of programmed cell death.
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Affiliation(s)
- Bryan Heit
- Hospital for Sick Children, Toronto, Ontario, Canada
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41
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The Role of Mitochondria in Glioma Pathophysiology. Mol Neurobiol 2010; 42:64-75. [DOI: 10.1007/s12035-010-8133-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Accepted: 04/05/2010] [Indexed: 10/19/2022]
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García-Sáez AJ, Ries J, Orzáez M, Pérez-Payà E, Schwille P. Membrane promotes tBID interaction with BCL(XL). Nat Struct Mol Biol 2009; 16:1178-85. [PMID: 19820711 DOI: 10.1038/nsmb.1671] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 08/14/2009] [Indexed: 12/23/2022]
Abstract
Two important questions on the molecular mechanism of the B cell CLL/lymphoma 2 (BCL2) proteins involve the interaction network between pro- and antiapoptotic members and the role of their translocation to the mitochondrial membrane during apoptosis. We used fluorescence correlation spectroscopy to quantify the molecular interactions of BH3-interacting domain death agonist (BID) and its truncated form tBID with the B cell lymphoma extra-large protein truncated at the C terminus (BCL(XL)DeltaCt) in solution and in membranes, and we found that (i) only the active form tBID binds to BCL(XL)DeltaCt and (ii) that the membrane strongly promotes binding between them. Particularly, a BH3 peptide from BID disrupts the tBID-BCL(XL) complex in solution, but only partially in lipid bilayers. These data indicate that tBID-BCL(XL) interactions in solution and lipid membranes are distinct, and they support a model in which BCL(XL) inhibition of tBID takes place predominantly at the membrane. Our findings imply an active role of the membrane in modulating the interactions between BCL2 proteins that has so far been underestimated.
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Petit PX, Dupaigne P, Pariselli F, Gonzalvez F, Etienne F, Rameau C, Bernard S. Interaction of the alpha-helical H6 peptide from the pro-apoptotic protein tBid with cardiolipin. FEBS J 2009; 276:6338-54. [DOI: 10.1111/j.1742-4658.2009.07345.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Cardiolipin and mitochondrial carriers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2048-58. [PMID: 19539604 DOI: 10.1016/j.bbamem.2009.06.007] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 06/04/2009] [Accepted: 06/04/2009] [Indexed: 12/16/2022]
Abstract
Members of the mitochondrial carrier family interact with cardiolipin (CL) as evident from a variety of functional and structural effects. CL stabilises carrier proteins on isolation with detergents, with the P(i) carrier as the prime example. CL is required for transport in reconstituted vesicles, prime examples are the P(i)- and ADP/ATP carrier (AAC). CL binds to the AAC in a graded manner; 6 CL/AAC dimer bind tightly as measured on the (31)P NMR time scale. 2 additional CL/dimer bind reversibly and a fast exchanging envelope of phospholipids includes CL as measured on the ESR time scale. In the crystal structure of the CAT-AAC complex 3 CL bind to the periphery of the AAC in a three-fold pseudo-symmetry. The binding of CL is implicated to contribute lowering the high transition energy barriers in the AAC. Para-functions of the AAC, as in the mitochondrial pore transition (MPT) and in cell death are linked to the CL binding of the AAC. Ca(++) or oxidants can sequester or destroy AAC bound CL, rendering AAC labile, allowing pore formation and degradation. Thus AAC, by being vital for energy transfer, constitutes an Achilles heel in the eukaryotic cell. AAC together with CL is also engaged in respiratory supercomplexes. Different from AAC the similarly structured uncoupling protein (UCP1) has no tightly bound CL, but CL addition lowers affinity of the inhibitory nucleotide binding that may contribute to the physiological regulation of the uncoupling activity by ATP.
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Abstract
The release of pro-apoptotic proteins from the mitochondria is a key event in cell death signaling that is regulated by Bcl-2 family proteins. For example, cleavage of the BH3-only protein, Bid, by multiple proteases leads to the formation of truncated Bid that, in turn, promotes the insertion/oligomerization of Bax into the mitochondrial outer membrane, resulting in pore formation and the release of proteins residing in the intermembrane space. Bax, a monomeric protein in the cytosol is targeted to the mitochondria by a yet unknown mechanism. Several proteins of the outer mitochondrial membrane have been proposed to act as receptors for Bax, among them the voltage-dependent anion channel, VDAC, and the mitochondrial protein translocase of the outer membrane, the TOM complex. Alternatively, the unique mitochondrial phospholipid, cardiolipin, has been ascribed a similar function. Here, we review recent work on the mechanisms of activation and the targeting of Bax to the mitochondria and discuss the advantages and limitations of the methods used to study this process.
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Paradies G, Petrosillo G, Paradies V, Ruggiero FM. Role of cardiolipin peroxidation and Ca2+ in mitochondrial dysfunction and disease. Cell Calcium 2009; 45:643-50. [PMID: 19368971 DOI: 10.1016/j.ceca.2009.03.012] [Citation(s) in RCA: 183] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 03/12/2009] [Accepted: 03/17/2009] [Indexed: 12/16/2022]
Abstract
Cardiolipin is a unique phospholipid which is almost exclusively located at the level of the inner mitochondrial membrane where it is biosynthesized. This phospholipid is known to be intimately involved in several mitochondrial bioenergetic processes. In addition, cardiolipin also has active roles in several of the mitochondrial-dependent steps of apoptosis and in mitochondrial membrane dynamics. Alterations in cardiolipin structure, content and acyl chains composition have been associated with mitochondrial dysfunction in multiple tissues in several physiopathological conditions, including ischemia/reperfusion, different thyroid states, diabetes, aging and heart failure. Cardiolipin is particularly susceptible to ROS attack due to its high content of unsaturated fatty acids. Oxidative damage to cardiolipin would negatively impact the biochemical function of the mitochondrial membranes altering membrane fluidity, ion permeability, structure and function of components of the mitochondrial electron transport chain, resulting in reduced mitochondrial oxidative phosphorylation efficiency and apoptosis. Diseases in which mitochondrial dysfunction has been linked to cardiolipin peroxidation are described. Ca(2+), particularly at high concentrations, appears to have several negative effects on mitochondrial function, some of these effects being linked to CL peroxidation. Cardiolipin peroxidation has been shown to participate, together with Ca(2+), in mitochondrial permeability transition. In this review, we provide an overview of the role of CL peroxidation and Ca(2+) in mitochondrial dysfunction and disease.
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Affiliation(s)
- Giuseppe Paradies
- Department of Biochemistry and Molecular Biology and CNR Institute of Biomembranes and Bioenergetics, University of Bari, Bari, Italy.
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47
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New insights into mitochondrial structure during cell death. Exp Neurol 2009; 218:183-92. [PMID: 19464290 DOI: 10.1016/j.expneurol.2009.05.021] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 04/30/2009] [Accepted: 05/08/2009] [Indexed: 01/06/2023]
Abstract
Mitochondria play a pivotal role in the cascade of events associated with cell death pathways that are involved with several forms of neurodegeneration. Recent findings show that in the Bax/Bak-dependent pathway of apoptosis, the release of cytochrome c from mitochondria is a consequence of two carefully coordinated events: opening of crista junctions triggered by OPA1 oligomer disassembly and formation of outer membrane pores. Both steps are necessary for the complete release of pro-apoptotic proteins. The remodeling of mitochondrial structure accompanies this pathway, including mitochondrial fission, and cristae and crista junction alterations. Yet, there is controversy surrounding the timing of certain remodeling events and whether they are necessary early events required for the release of pro-apoptotic factors or are simply a downstream after-effect. Here, we analyze the current knowledge of mitochondrial remodeling during cell death and discuss what structural alterations occur to this organelle during neurodegeneration, focusing on the higher resolution structural correlates obtained by electron microscopy and electron tomography.
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Manara A, Lindsay J, Marchioretto M, Astegno A, Gilmore AP, Esposti MD, Crimi M. Bid binding to negatively charged phospholipids may not be required for its pro-apoptotic activity in vivo. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:997-1010. [PMID: 19463967 DOI: 10.1016/j.bbalip.2009.05.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 05/08/2009] [Accepted: 05/13/2009] [Indexed: 01/07/2023]
Abstract
Bid is a ubiquitous pro-apoptotic member of the Bcl-2 family that has been involved in a variety of pathways of cell death. Unique among pro-apoptotic proteins, Bid is activated after cleavage by the apical caspases of the extrinsic pathway; subsequently it moves to mitochondria, where it promotes the release of apoptogenic proteins in concert with other Bcl-2 family proteins like Bak. Diverse factors appear to modulate the pro-apoptotic action of Bid, from its avid binding to mitochondrial lipids (in particular, cardiolipin) to multiple phosphorylations at sites that can modulate its caspase cleavage. This work addresses the question of how the lipid interactions of Bid that are evident in vitro actually impact on its pro-apoptotic action within cells. Using site-directed mutagenesis, we identified mutations that reduced mouse Bid lipid binding in vitro. Mutation of the conserved residue Lys157 specifically decreased the binding to negatively charged lipids related to cardiolipin and additionally affected the rate of caspase cleavage. However, this lipid-binding mutant had no discernable effect on Bid pro-apoptotic function in vivo. The results are interpreted in relation to an underlying interaction of Bid with lysophosphatidylcholine, which is not disrupted in any mutant retaining pro-apoptotic function both in vitro and in vivo.
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Affiliation(s)
- Anna Manara
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
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Mitochondrial kinases and their molecular interaction with cardiolipin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:2032-47. [PMID: 19409873 DOI: 10.1016/j.bbamem.2009.04.018] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Accepted: 04/24/2009] [Indexed: 11/22/2022]
Abstract
Mitochondrial isoforms of creatine kinase (MtCK) and nucleoside diphosphate kinase (NDPK-D) are not phylogenetically related but share functionally important properties. They both use mitochondrially generated ATP with the ultimate goal of maintaining proper nucleotide pools, are located in the intermembrane/cristae space, have symmetrical oligomeric structures, and show high affinity binding to anionic phospholipids, in particular cardiolipin. The structural basis and functional consequences of the cardiolipin interaction have been studied and are discussed in detail in this review. They mainly result in a functional interaction of MtCK and NDPK-D with inner membrane adenylate translocator, probably by forming proteolipid complexes. These interactions allow for privileged exchange of metabolites (channeling) that ultimately regulate mitochondrial respiration. Further functions of the MtCK/membrane interaction include formation of cardiolipin membrane patches, stabilization of mitochondria and a role in apoptotic signaling, as well as in case of both kinases, a role in facilitating lipid transfer between two membranes. Finally, disturbed cardiolipin interactions of MtCK, NDPK-D and other proteins like cytochrome c and truncated Bid are discussed more generally in the context of apoptosis and necrosis.
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Schafer B, Quispe J, Choudhary V, Chipuk JE, Ajero TG, Du H, Schneiter R, Kuwana T. Mitochondrial outer membrane proteins assist Bid in Bax-mediated lipidic pore formation. Mol Biol Cell 2009; 20:2276-85. [PMID: 19244344 DOI: 10.1091/mbc.e08-10-1056] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial outer membrane permeabilization (MOMP) is a critical step in apoptosis and is regulated by Bcl-2 family proteins. In vitro systems using cardiolipin-containing liposomes have demonstrated the key features of MOMP induced by Bax and cleaved Bid; however, the nature of the "pores" and how they are formed remain obscure. We found that mitochondrial outer membranes contained very little cardiolipin, far less than that required for liposome permeabilization, despite their responsiveness to Bcl-2 family proteins. Strikingly, the incorporation of isolated mitochondrial outer membrane (MOM) proteins into liposomes lacking cardiolipin conferred responsiveness to cleaved Bid and Bax. Cardiolipin dependence was observed only when permeabilization was induced with cleaved Bid but not with Bid or Bim BH3 peptide or oligomerized Bax. Therefore, we conclude that MOM proteins specifically assist cleaved Bid in Bax-mediated permeabilization. Cryoelectron microscopy of cardiolipin-liposomes revealed that cleaved Bid and Bax produced large round holes with diameters of 25-100 nm, suggestive of lipidic pores. In sum, we propose that activated Bax induces lipidic pore formation and that MOM proteins assist cleaved Bid in this process in the absence of cardiolipin.
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Affiliation(s)
- Blanca Schafer
- Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, 52242, USA
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