1
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Miller MS, Cowan AD, Brouwer JM, Smyth ST, Peng L, Wardak AZ, Uren RT, Luo C, Roy MJ, Shah S, Tan Z, Reid GE, Colman PM, Czabotar PE. Sequence differences between BAX and BAK core domains manifest as differences in their interactions with lipids. FEBS J 2024; 291:2335-2353. [PMID: 38088212 DOI: 10.1111/febs.17031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/07/2023] [Accepted: 12/11/2023] [Indexed: 01/21/2024]
Abstract
The B-cell lymphoma 2 (BCL2) family members, BCL2-associated protein X (BAX) and BCL2 homologous antagonist killer (BAK), are required for programmed cell death via the mitochondrial pathway. When cells are stressed, damaged or redundant, the balance of power between the BCL2 family of proteins shifts towards BAX and BAK, allowing their transition from an inactive, monomeric state to a membrane-active oligomeric form that releases cytochrome c from the mitochondrial intermembrane space. That oligomeric state has an essential intermediate, a symmetric homodimer of BAX or BAK. Here we describe crystal structures of dimers of the core domain of BAX, comprising its helices α2-α5. These structures provide an atomic resolution description of the interactions that drive BAX homo-dimerisation and insights into potential interaction between core domain dimers and membrane lipids. The previously identified BAK lipid-interacting sites are not conserved with BAX and are likely to determine the differences between them in their interactions with lipids. We also describe structures of heterodimers of BAK/BAX core domains, yielding further insight into the differences in lipid binding between BAX and BAK.
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Affiliation(s)
- Michelle S Miller
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
- Department of Medical Biology, University of Melbourne, Parkville, Vic., Australia
| | - Angus D Cowan
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
- Department of Medical Biology, University of Melbourne, Parkville, Vic., Australia
| | - Jason M Brouwer
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
- Department of Medical Biology, University of Melbourne, Parkville, Vic., Australia
| | - Sean T Smyth
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
| | - Liuyu Peng
- School of Chemistry, University of Melbourne, Parkville, Vic., Australia
| | - Ahmad Z Wardak
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
| | - Rachel T Uren
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
- Department of Medical Biology, University of Melbourne, Parkville, Vic., Australia
| | - Cindy Luo
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
| | - Michael J Roy
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
- Department of Medical Biology, University of Melbourne, Parkville, Vic., Australia
| | - Sayali Shah
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
- Department of Medical Biology, University of Melbourne, Parkville, Vic., Australia
| | - Ziwen Tan
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
- Department of Medical Biology, University of Melbourne, Parkville, Vic., Australia
| | - Gavin E Reid
- School of Chemistry, University of Melbourne, Parkville, Vic., Australia
- Department of Biochemistry and Pharmacology, University of Melbourne, Parkville, Vic., Australia
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Vic., Australia
| | - Peter M Colman
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
- Department of Medical Biology, University of Melbourne, Parkville, Vic., Australia
| | - Peter E Czabotar
- Walter and Eliza Hall Institute of Medical Research, Parkville, Vic., Australia
- Department of Medical Biology, University of Melbourne, Parkville, Vic., Australia
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2
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Lestari B, Fukushima T, Utomo RY, Wahyuningsih MSH. Apoptotic and non-apoptotic roles of caspases in placenta physiology and pathology. Placenta 2024; 151:37-47. [PMID: 38703713 DOI: 10.1016/j.placenta.2024.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/12/2024] [Accepted: 03/27/2024] [Indexed: 05/06/2024]
Abstract
Caspases, a family of cysteine proteases, are pivotal regulators of apoptosis, the tightly controlled cell death process crucial for eliminating excessive or unnecessary cells during development, including placental development. Collecting research has unveiled the multifaceted roles of caspases in the placenta, extending beyond apoptosis. Apart from their involvement in placental tissue remodeling via apoptosis, caspases actively participate in essential regulatory processes, such as trophoblast fusion and differentiation, significantly influencing placental growth and functionality. In addition, growing evidence indicates an elevation in caspase activity under pathological conditions like pre-eclampsia (PE) and intrauterine growth restriction (IUGR), leading to excessive cell death as well as inflammation. Drawing from advancements in caspase research and placental development under both normal and abnormal conditions, we examine the significance of caspases in both cell death (apoptosis) and non-cell death-related processes within the placenta. We also discuss potential therapeutics targeting caspase-related pathways for placenta disorders.
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Affiliation(s)
- Beni Lestari
- Department Pharmacology and Therapy, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia; Cancer Chemoprevention Research Center, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Toshiaki Fukushima
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Japan.
| | - Rohmad Yudi Utomo
- Cancer Chemoprevention Research Center, Universitas Gadjah Mada, Yogyakarta, Indonesia; Department Pharmaceutical Chemistry, Faculty of Pharmacy, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Mae Sri Hartati Wahyuningsih
- Department Pharmacology and Therapy, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia.
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3
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Jenner A, Garcia-Saez AJ. The regulation of the apoptotic pore-An immunological tightrope walk. Adv Immunol 2024; 162:59-108. [PMID: 38866439 DOI: 10.1016/bs.ai.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Apoptotic pore formation in mitochondria is the pivotal point for cell death during mitochondrial apoptosis. It is regulated by BCL-2 family proteins in response to various cellular stress triggers and mediates mitochondrial outer membrane permeabilization (MOMP). This allows the release of mitochondrial contents into the cytosol, which triggers rapid cell death and clearance through the activation of caspases. However, under conditions of low caspase activity, the mitochondrial contents released into the cytosol through apoptotic pores serve as inflammatory signals and activate various inflammatory responses. In this chapter, we discuss how the formation of the apoptotic pore is regulated by BCL-2 proteins as well as other cellular or mitochondrial proteins and membrane lipids. Moreover, we highlight the importance of sublethal MOMP in the regulation of mitochondrial-activated inflammation and discuss its physiological consequences in the context of pathogen infection and disease and how it can potentially be exploited therapeutically, for example to improve cancer treatment.
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Affiliation(s)
- Andreas Jenner
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Ana J Garcia-Saez
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
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4
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King LE, Hohorst L, García-Sáez AJ. Expanding roles of BCL-2 proteins in apoptosis execution and beyond. J Cell Sci 2023; 136:jcs260790. [PMID: 37994778 DOI: 10.1242/jcs.260790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023] Open
Abstract
The proteins of the BCL-2 family are known as key regulators of apoptosis, with interactions between family members determining permeabilisation of the mitochondrial outer membrane (MOM) and subsequent cell death. However, the exact mechanism through which they form the apoptotic pore responsible for MOM permeabilisation (MOMP), the structure and specific components of this pore, and what roles BCL-2 proteins play outside of directly regulating MOMP are incompletely understood. Owing to the link between apoptosis dysregulation and disease, the BCL-2 proteins are important targets for drug development. With the development and clinical use of drugs targeting BCL-2 proteins showing success in multiple haematological malignancies, enhancing the efficacy of these drugs, or indeed developing novel drugs targeting BCL-2 proteins is of great interest to treat cancer patients who have developed resistance or who suffer other disease types. Here, we review our current understanding of the molecular mechanism of MOMP, with a particular focus on recently discovered roles of BCL-2 proteins in apoptosis and beyond, and discuss what implications these functions might have in both healthy tissues and disease.
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Affiliation(s)
- Louise E King
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne 50931, Germany
| | - Lisa Hohorst
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne 50931, Germany
| | - Ana J García-Sáez
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne 50931, Germany
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5
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Czabotar PE, Garcia-Saez AJ. Mechanisms of BCL-2 family proteins in mitochondrial apoptosis. Nat Rev Mol Cell Biol 2023; 24:732-748. [PMID: 37438560 DOI: 10.1038/s41580-023-00629-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 07/14/2023]
Abstract
The proteins of the BCL-2 family are key regulators of mitochondrial apoptosis, acting as either promoters or inhibitors of cell death. The functional interplay and balance between the opposing BCL-2 family members control permeabilization of the outer mitochondrial membrane, leading to the release of activators of the caspase cascade into the cytosol and ultimately resulting in cell death. Despite considerable research, our knowledge about the mechanisms of the BCL-2 family of proteins remains insufficient, which complicates cell fate predictions and does not allow us to fully exploit these proteins as targets for drug discovery. Detailed understanding of the formation and molecular architecture of the apoptotic pore in the outer mitochondrial membrane remains a holy grail in the field, but new studies allow us to begin constructing a structural model of its arrangement. Recent literature has also revealed unexpected activities for several BCL-2 family members that challenge established concepts of how they regulate mitochondrial permeabilization. In this Review, we revisit the most important advances in the field and integrate them into a new structure-function-based classification of the BCL-2 family members that intends to provide a comprehensive model for BCL-2 action in apoptosis. We close this Review by discussing the potential of drugging the BCL-2 family in diseases characterized by aberrant apoptosis.
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Affiliation(s)
- Peter E Czabotar
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia.
| | - Ana J Garcia-Saez
- Membrane Biophysics, Institute of Genetics, CECAD, University of Cologne, Cologne, Germany.
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6
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Shalaby R, Diwan A, Flores-Romero H, Hertlein V, Garcia-Saez AJ. Visualization of BOK pores independent of BAX and BAK reveals a similar mechanism with differing regulation. Cell Death Differ 2023; 30:731-741. [PMID: 36289446 PMCID: PMC9607731 DOI: 10.1038/s41418-022-01078-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/07/2022] Open
Abstract
BOK is a poorly understood member of the BCL-2 family of proteins that has been proposed to function as a pro-apoptotic, BAX-like effector. However, the molecular mechanism and structural properties of BOK pores remain enigmatic. Here, we show that the thermal stability and pore activity of BOK depends on the presence of its C-terminus as well as on the mitochondrial lipid cardiolipin. We directly visualized BOK pores in liposomes by electron microscopy, which appeared similar to those induced by BAX, in line with comparable oligomerization properties quantified by single molecule imaging. In addition, super-resolution STED imaging revealed that BOK organized into dots and ring-shaped assemblies in apoptotic mitochondria, also reminiscent of those found for BAX and BAK. Yet, unlike BAX and BAK, the apoptotic activity of BOK was limited by partial mitochondrial localization and was independent of and unaffected by other BCL-2 proteins. These results suggest that, while BOK activity is kept in check by subcellular localization instead of interaction with BCL-2 family members, the resulting pores are structurally similar to those of BAX and BAK.
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Affiliation(s)
- Raed Shalaby
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, 50931, Cologne, Germany
| | - Arzoo Diwan
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, 50931, Cologne, Germany
| | - Hector Flores-Romero
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, 50931, Cologne, Germany
| | - Vanessa Hertlein
- Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Ana J Garcia-Saez
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, 50931, Cologne, Germany.
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7
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Moldoveanu T. Apoptotic mitochondrial poration by a growing list of pore-forming BCL-2 family proteins. Bioessays 2023; 45:e2200221. [PMID: 36650950 PMCID: PMC9975053 DOI: 10.1002/bies.202200221] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/31/2022] [Accepted: 01/02/2023] [Indexed: 01/19/2023]
Abstract
The pore-forming BCL-2 family proteins are effectors of mitochondrial poration in apoptosis initiation. Two atypical effectors-BOK and truncated BID (tBID)-join the canonical effectors BAK and BAX. Gene knockout revealed developmental phenotypes in the absence the effectors, supporting their roles in vivo. During apoptosis effectors are activated and change shape from dormant monomers to dynamic oligomers that associate with and permeabilize mitochondria. BID is activated by proteolysis, BOK accumulates on inhibition of its degradation by the E3 ligase gp78, while BAK and BAX undergo direct activation by BH3-only initiators, autoactivation, and crossactivation. Except tBID, effector oligomers on the mitochondria appear as arcs and rings in super-resolution microscopy images. The BH3-in-groove dimers of BAK and BAX, the tBID monomers, and uncharacterized BOK species are the putative building blocks of apoptotic pores. Effectors interact with lipids and bilayers but the mechanism of membrane poration remains elusive. I discuss effector-mediated mitochondrial poration.
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Affiliation(s)
- Tudor Moldoveanu
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences,Correspondence:
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8
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Bonzerato CG, Wojcikiewicz RJH. Bok: real killer or bystander with non-apoptotic roles? Front Cell Dev Biol 2023; 11:1161910. [PMID: 37123400 PMCID: PMC10130511 DOI: 10.3389/fcell.2023.1161910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 04/05/2023] [Indexed: 05/02/2023] Open
Abstract
Bcl-2-related ovarian killer, Bok, was first labeled "pro-apoptotic" due to its ability to cause cell death when over-expressed. However, it has become apparent that this is not a good name, since Bok is widely expressed in tissues other than ovaries. Further, there is serious doubt as to whether Bok is a real "killer," due to disparities in the ability of over-expressed versus endogenous Bok to trigger apoptosis. In this brief review, we rationalize these disparities and argue that endogenous Bok is very different from the pro-apoptotic, mitochondrial outer membrane permeabilization mediators, Bak and Bax. Instead, Bok is a stable, endoplasmic reticulum-located protein bound to inositol 1,4,5 trisphosphate receptors. From this location, Bok plays a variety of roles, including regulation of endoplasmic reticulum/mitochondria contact sites and mitochondrial dynamics. Therefore, categorizing Bok as a "killer" may well be misleading and instead, endogenous Bok would better be considered an endoplasmic reticulum-located "bystander", with non-apoptotic roles.
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9
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Pore-forming proteins as drivers of membrane permeabilization in cell death pathways. Nat Rev Mol Cell Biol 2022; 24:312-333. [PMID: 36543934 DOI: 10.1038/s41580-022-00564-w] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2022] [Indexed: 12/24/2022]
Abstract
Regulated cell death (RCD) relies on activation and recruitment of pore-forming proteins (PFPs) that function as executioners of specific cell death pathways: apoptosis regulator BAX (BAX), BCL-2 homologous antagonist/killer (BAK) and BCL-2-related ovarian killer protein (BOK) for apoptosis, gasdermins (GSDMs) for pyroptosis and mixed lineage kinase domain-like protein (MLKL) for necroptosis. Inactive precursors of PFPs are converted into pore-forming entities through activation, membrane recruitment, membrane insertion and oligomerization. These mechanisms involve protein-protein and protein-lipid interactions, proteolytic processing and phosphorylation. In this Review, we discuss the structural rearrangements incurred by RCD-related PFPs and describe the mechanisms that manifest conversion from autoinhibited to membrane-embedded molecular states. We further discuss the formation and maturation of membrane pores formed by BAX/BAK/BOK, GSDMs and MLKL, leading to diverse pore architectures. Lastly, we highlight commonalities and differences of PFP mechanisms involving BAX/BAK/BOK, GSDMs and MLKL and conclude with a discussion on how, in a population of challenged cells, the coexistence of cell death modalities may have profound physiological and pathophysiological implications.
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10
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Bonzerato CG, Keller KR, Schulman JJ, Gao X, Szczesniak LM, Wojcikiewicz RJH. Endogenous Bok is stable at the endoplasmic reticulum membrane and does not mediate proteasome inhibitor-induced apoptosis. Front Cell Dev Biol 2022; 10:1094302. [PMID: 36601536 PMCID: PMC9806350 DOI: 10.3389/fcell.2022.1094302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022] Open
Abstract
Controversy surrounds the cellular role of the Bcl-2 family protein Bok. On one hand, it has been shown that all endogenous Bok is bound to inositol 1,4,5-trisphosphate receptors (IP3Rs), while other data suggest that Bok can act as a pro-apoptotic mitochondrial outer membrane permeabilization mediator, apparently kept at very low and non-apoptotic levels by efficient proteasome-mediated degradation. Here we show that 1) endogenous Bok is expressed at readily-detectable levels in key cultured cells (e.g., mouse embryonic fibroblasts and HCT116 cells) and is not constitutively degraded by the proteasome, 2) proteasome inhibitor-induced apoptosis is not mediated by Bok, 3) endogenous Bok expression level is critically dependent on the presence of IP3Rs, 4) endogenous Bok is rapidly degraded by the ubiquitin-proteasome pathway in the absence of IP3Rs at the endoplasmic reticulum membrane, and 5) charged residues in the transmembrane region of Bok affect its stability, ability to interact with Mcl-1, and pro-apoptotic activity when over-expressed. Overall, these data indicate that endogenous Bok levels are not governed by proteasomal activity (except when IP3Rs are deleted) and that while endogenous Bok plays little or no role in apoptotic signaling, exogenous Bok can mediate apoptosis in a manner dependent on its transmembrane domain.
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11
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Sekar G, Singh G, Qin X, Guibao CD, Schwam B, Inde Z, Grace CR, Zhang W, Slavish PJ, Lin W, Chen T, Lee RE, Rankovic Z, Sarosiek K, Moldoveanu T. Small molecule SJ572946 activates BAK to initiate apoptosis. iScience 2022; 25:105064. [PMID: 36147946 PMCID: PMC9485059 DOI: 10.1016/j.isci.2022.105064] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 06/29/2022] [Accepted: 08/30/2022] [Indexed: 01/11/2023] Open
Abstract
Poration of the outer mitochondrial membrane by the effector BCL-2 proteins BAK and BAX initiates apoptosis. BH3-only initiators BID and BIM trigger conformational changes in BAK and BAX transforming them from globular dormant proteins to oligomers of the apoptotic pores. Small molecules that can directly activate effectors are being sought for applications in cancer treatment. Here, we describe the small molecule SJ572946, discovered in a fragment-based screen that binds to the activation groove of BAK and selectively triggers BAK activation over that of BAX in liposome and mitochondrial permeabilization assays. SJ572946 independently kills BAK-expressing BCL2allKO HCT116 cells revealing on target cellular activity. In combination with apoptotic inducers and BH3 mimetics, SJ572946 kills experimental cancer cell lines. SJ572946 also cooperates with the endogenous BAK activator BID in activating a misfolded BAK mutant substantially impaired in activation. SJ572946 is a proof-of-concept tool for probing BAK-mediated apoptosis in preclinical cancer research.
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Affiliation(s)
- Giridhar Sekar
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA,Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Geetika Singh
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA,Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA,Children’s GMP, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Xingping Qin
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston,02115 MA, USA,Program in Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, 02115 MA, USA,Laboratory of Systems Pharmacology, Harvard Medical School, Boston,02115 MA, USA
| | - Cristina D. Guibao
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Brittany Schwam
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA,Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Zintis Inde
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston,02115 MA, USA,Program in Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, 02115 MA, USA,Laboratory of Systems Pharmacology, Harvard Medical School, Boston,02115 MA, USA
| | - Christy R. Grace
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Weixing Zhang
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - P. Jake Slavish
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Wenwei Lin
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Richard E. Lee
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Zoran Rankovic
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Kristopher Sarosiek
- John B. Little Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston,02115 MA, USA,Program in Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, 02115 MA, USA,Laboratory of Systems Pharmacology, Harvard Medical School, Boston,02115 MA, USA
| | - Tudor Moldoveanu
- Department of Structural Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA,Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA,Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Roeck, AR 72205, USA,Corresponding author
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12
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Walter F, D’Orsi B, Jagannathan A, Dussmann H, Prehn JHM. BOK controls ER proteostasis and physiological ER stress responses in neurons. Front Cell Dev Biol 2022; 10:915065. [PMID: 36060797 PMCID: PMC9434404 DOI: 10.3389/fcell.2022.915065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
The Bcl-2 family proteins BAK and BAX control the crucial step of pore formation in the mitochondrial outer membrane during intrinsic apoptosis. Bcl-2-related ovarian killer (BOK) is a Bcl-2 family protein with a high sequence similarity to BAK and BAX. However, intrinsic apoptosis can proceed in the absence of BOK. Unlike BAK and BAX, BOK is primarily located on the endoplasmic reticulum (ER) and Golgi membranes, suggesting a role for BOK in regulating ER homeostasis. In this study, we report that BOK is required for a full ER stress response. Employing previously characterized fluorescent protein-based ER stress reporter cell systems, we show that BOK-deficient cells have an attenuated response to ER stress in all three signaling branches of the unfolded protein response. Fluo-4-based confocal Ca2+ imaging revealed that disruption of ER proteostasis in BOK-deficient cells was not linked to altered ER Ca2+ levels. Fluorescence recovery after photobleaching (FRAP) experiments using GRP78/BiP-eGFP demonstrated that GRP78 motility was significantly lower in BOK-deficient cells. This implied that less intraluminal GRP78 was freely available and more of the ER chaperone bound to unfolded proteins. Collectively, these experiments suggest a new role for BOK in the protection of ER proteostasis and cellular responses to ER stress.
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Affiliation(s)
- Franziska Walter
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland University of Medicine and Health Sciences, Dublin, Ireland
- SFI FutureNeuro Research Centre, Royal College of Surgeons in Ireland University of Medicine and Health Sciences, Dublin, Ireland
| | - Beatrice D’Orsi
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland University of Medicine and Health Sciences, Dublin, Ireland
- Institute of Neuroscience, Italian National Research Council, Pisa, Italy
| | - Anagha Jagannathan
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland University of Medicine and Health Sciences, Dublin, Ireland
| | - Heiko Dussmann
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland University of Medicine and Health Sciences, Dublin, Ireland
| | - Jochen H. M. Prehn
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland University of Medicine and Health Sciences, Dublin, Ireland
- SFI FutureNeuro Research Centre, Royal College of Surgeons in Ireland University of Medicine and Health Sciences, Dublin, Ireland
- *Correspondence: Jochen H. M. Prehn,
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13
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SARS-CoV-2 membrane protein causes the mitochondrial apoptosis and pulmonary edema via targeting BOK. Cell Death Differ 2022; 29:1395-1408. [PMID: 35022571 PMCID: PMC8752586 DOI: 10.1038/s41418-022-00928-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 12/18/2021] [Accepted: 12/28/2021] [Indexed: 12/18/2022] Open
Abstract
Deaths caused by coronavirus disease 2019 (COVID-19) are largely due to the lungs edema resulting from the disruption of the lung alveolo-capillary barrier, induced by SARS-CoV-2-triggered pulmonary cell apoptosis. However, the molecular mechanism underlying the proapoptotic role of SARS-CoV-2 is still unclear. Here, we revealed that SARS-CoV-2 membrane (M) protein could induce lung epithelial cells mitochondrial apoptosis. Notably, M protein stabilized B-cell lymphoma 2 (BCL-2) ovarian killer (BOK) via inhibiting its ubiquitination and promoted BOK mitochondria translocation. The endodomain of M protein was required for its interaction with BOK. Knockout of BOK by CRISPR/Cas9 increased cellular resistance to M protein-induced apoptosis. BOK was rescued in the BOK-knockout cells, which led to apoptosis induced by M protein. M protein induced BOK to trigger apoptosis in the absence of BAX and BAK. Furthermore, the BH2 domain of BOK was required for interaction with M protein and proapoptosis. In vivo M protein recombinant lentivirus infection induced caspase-associated apoptosis and increased alveolar-capillary permeability in the mouse lungs. BOK knockdown improved the lung edema due to lentivirus-M protein infection. Overall, M protein activated the BOK-dependent apoptotic pathway and thus exacerbated SARS-CoV-2 associated lung injury in vivo. These findings proposed a proapoptotic role for M protein in SARS-CoV-2 pathogenesis, which may provide potential targets for COVID-19 treatments. In SARS-CoV-2-infected lung epithelial cells, endodomain of M protein binds to the BH2 domain of BOK and inhibits ubiquitination. BOK is stabilized and translocate to the mitochondrial outer membrane, promoting Cyt c release. Cyt c released outside the mitochondria activates CASP 9 mediated apoptosis, thereby inducing pulmonary edema. ![]()
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14
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The BCL-2 family member BOK promotes KRAS-driven lung cancer progression in a p53-dependent manner. Oncogene 2022; 41:1376-1382. [PMID: 35091677 PMCID: PMC8881215 DOI: 10.1038/s41388-021-02161-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 12/01/2021] [Accepted: 12/16/2021] [Indexed: 12/12/2022]
Abstract
A variety of cancer entities are driven by KRAS mutations, which remain difficult to target clinically. Survival pathways, such as resistance to cell death, may represent a promising treatment approach in KRAS mutated cancers. Based on the frequently observed genomic deletions of BCL-2-related ovarian killer (BOK) in cancer patients, we explored the function of BOK in a mutant KrasG12D-driven murine model of lung cancer. Using KrasG12D/+Bok−/− mice, we observed an overall tumor-promoting function of BOK in vivo. Specifically, loss of BOK reduced proliferation both in cell lines in vitro as well as in KrasG12D-driven tumor lesions in vivo. During tumor development in vivo, loss of BOK resulted in a lower tumor burden, with fewer, smaller, and less advanced tumors. Using KrasG12D/+Tp53Δ/ΔBok−/− mice, we identified that this phenotype was entirely dependent on the presence of functional p53. Furthermore, analysis of a human dataset of untreated early-stage lung tumors did not identify any common deletion of the BOK locus, independently of the TP53 status or the histopathological classification. Taken together our data indicate that BOK supports tumor progression in Kras-driven lung cancer.
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15
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Singh G, Guibao CD, Seetharaman J, Aggarwal A, Grace CR, McNamara DE, Vaithiyalingam S, Waddell MB, Moldoveanu T. Structural basis of BAK activation in mitochondrial apoptosis initiation. Nat Commun 2022; 13:250. [PMID: 35017502 PMCID: PMC8752837 DOI: 10.1038/s41467-021-27851-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 12/14/2021] [Indexed: 12/31/2022] Open
Abstract
BCL-2 proteins regulate mitochondrial poration in apoptosis initiation. How the pore-forming BCL-2 Effector BAK is activated remains incompletely understood mechanistically. Here we investigate autoactivation and direct activation by BH3-only proteins, which cooperate to lower BAK threshold in membrane poration and apoptosis initiation. We define in trans BAK autoactivation as the asymmetric “BH3-in-groove” triggering of dormant BAK by active BAK. BAK autoactivation is mechanistically similar to direct activation. The structure of autoactivated BAK BH3-BAK complex reveals the conformational changes leading to helix α1 destabilization, which is a hallmark of BAK activation. Helix α1 is destabilized and restabilized in structures of BAK engaged by rationally designed, high-affinity activating and inactivating BID-like BH3 ligands, respectively. Altogether our data support the long-standing hit-and-run mechanism of BAK activation by transient binding of BH3-only proteins, demonstrating that BH3-induced structural changes are more important in BAK activation than BH3 ligand affinity. The authors show that the mechanism of BAK activation in mitochondrial apoptosis involves cooperation between direct activation by BH3-only protein BID and BAK autoactivation, providing a unifying basis for BAK triggering by BH3 ligands.
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Affiliation(s)
- Geetika Singh
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.,Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA.,Integrative Biomedical Sciences Program, University of Tennessee Health Sciences Center, Memphis, TN, 38163, USA
| | - Cristina D Guibao
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.,Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Jayaraman Seetharaman
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Anup Aggarwal
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.,Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Christy R Grace
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Dan E McNamara
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.,Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | | | - M Brett Waddell
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Tudor Moldoveanu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA. .,Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA.
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16
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Pogmore JP, Uehling D, Andrews DW. Pharmacological Targeting of Executioner Proteins: Controlling Life and Death. J Med Chem 2021; 64:5276-5290. [PMID: 33939407 DOI: 10.1021/acs.jmedchem.0c02200] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Small-molecule mediated modulation of protein interactions of Bcl-2 (B-cell lymphoma-2) family proteins was clinically validated in 2015 when Venetoclax, a selective inhibitor of the antiapoptotic protein BCL-2, achieved breakthrough status designation by the FDA for treatment of lymphoid malignancies. Since then, substantial progress has been made in identifying inhibitors of other interactions of antiapoptosis proteins. However, targeting their pro-apoptotic counterparts, the "executioners" BAX, BAK, and BOK that both initiate and commit the cell to dying, has lagged behind. However, recent publications demonstrate that these proteins can be positively or negatively regulated using small molecule tool compounds. The results obtained with these molecules suggest that pharmaceutical regulation of apoptosis will have broad implications that extend beyond activating cell death in cancer. We review recent advances in identifying compounds and their utility in the exogenous control of life and death by regulating executioner proteins, with emphasis on the prototype BAX.
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Affiliation(s)
- Justin P Pogmore
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1J7, Canada.,Biological Sciences, Sunnybrook Research Institute, University of Toronto, Toronto, Ontario M4N 3M5, Canada
| | - David Uehling
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario M5G 1M1, Canada
| | - David W Andrews
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1J7, Canada.,Biological Sciences, Sunnybrook Research Institute, University of Toronto, Toronto, Ontario M4N 3M5, Canada
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17
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Szczesniak LM, Bonzerato CG, Schulman JJ, Bah A, Wojcikiewicz RJH. Bok binds to a largely disordered loop in the coupling domain of type 1 inositol 1,4,5-trisphosphate receptor. Biochem Biophys Res Commun 2021; 553:180-186. [PMID: 33773141 DOI: 10.1016/j.bbrc.2021.03.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 03/09/2021] [Indexed: 12/28/2022]
Abstract
Bcl-2-related ovarian killer (Bok) binds tightly to inositol 1,4,5-trisphosphate receptors (IP3Rs). To better understand this interaction, we sought to elucidate the Bok binding determinants in IP3R1, focusing on the ∼75 amino acid loop (residues 1882-1957) between α helices 72 and 73. Bioinformatic analysis revealed that the majority of this loop is intrinsically disordered, with two flanking regions of high disorder next to a low disorder central region (∼residues 1914-1926) that is predicted to contain two fused, disjointed transient helical elements. Experiments with IP3R1 mutants, combined with computational analysis, indicated that small deletions in this central region block Bok binding due to perturbation of the helical elements. Studies in vitro with purified Bok and IP3R1-derived peptides revealed high affinity binding to amino acids 1898-1940 of IP3R1 (Kd ∼65 nM) and that binding affinity is also dependent upon both of the high disorder flanking regions. The strength of the Bok-IP3R1 interaction was demonstrated by the ability of IP3R1 or Bok to recruit transmembrane domain-free Bok or IP3R1 mutants, respectively, to membranes in intact cells, and that these two mutants can bind in the cytosol independently of membrane association. Overall, we show that Bok binding to IP3R1 occurs within a largely disordered loop between α helices 72 and 73 and that high affinity binding is mediated by multivalent interactions.
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Affiliation(s)
- Laura M Szczesniak
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Caden G Bonzerato
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY, USA
| | | | - Alaji Bah
- Department of Biochemistry, Department of Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
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18
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Li Q, Shi N, Cai C, Zhang M, He J, Tan Y, Fu W. The Role of Mitochondria in Pyroptosis. Front Cell Dev Biol 2021; 8:630771. [PMID: 33553170 PMCID: PMC7859326 DOI: 10.3389/fcell.2020.630771] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 12/28/2020] [Indexed: 11/25/2022] Open
Abstract
Pyroptosis is a recently discovered aspartic aspart-specific cysteine protease (Caspase-1/4/5/11) dependent mode of gene-regulated cell death cell death, which is represented by the rupture of cell membrane perforations and the production of proinflammatory mediaters like interleukin-18(IL-18) and interleukin-1β (IL-1β). Mitochondria also play an important role in apoptotic cell death. When it comes to apoptosis of mitochondrion, mitochondrial outer membrane permeabilization (MOMP) is commonly known to cause cell death. As a downstream pathological process of apoptotic signaling, MOMP participates in the leakage of cytochrome-c from mitochondrion to the cytosol and subsequently activate caspase proteases. Hence, targeting MOMP for the sake of manipulating cell death presents potential therapeutic effects among various types of diseases, such as autoimmune disorders, neurodegenerative diseases, and cancer. In this review, we highlights the roles and significance of mitochondria in pyroptosis to provide unexplored strategies that target the mitochondria to regulate cell death for clinical benefits.
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Affiliation(s)
- Qian Li
- Department of Emergency Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Nengxian Shi
- Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Chen Cai
- Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Mingming Zhang
- Department of Burns, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jing He
- Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ying Tan
- Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Weijun Fu
- Department of Critical Care Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
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19
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The Mysteries around the BCL-2 Family Member BOK. Biomolecules 2020; 10:biom10121638. [PMID: 33291826 PMCID: PMC7762061 DOI: 10.3390/biom10121638] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 11/30/2020] [Accepted: 12/02/2020] [Indexed: 12/19/2022] Open
Abstract
BOK is an evolutionarily conserved BCL-2 family member that resembles the apoptotic effectors BAK and BAX in sequence and structure. Based on these similarities, BOK has traditionally been classified as a BAX-like pro-apoptotic protein. However, the mechanism of action and cellular functions of BOK remains controversial. While some studies propose that BOK could replace BAK and BAX to elicit apoptosis, others attribute to this protein an indirect way of apoptosis regulation. Adding to the debate, BOK has been associated with a plethora of non-apoptotic functions that makes this protein unpredictable when dictating cell fate. Here, we compile the current knowledge and open questions about this paradoxical protein with a special focus on its structural features as the key aspect to understand BOK biological functions.
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20
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Shan R, Liu N, Yan Y, Liu B. Apoptosis, autophagy and atherosclerosis: Relationships and the role of Hsp27. Pharmacol Res 2020; 166:105169. [PMID: 33053445 DOI: 10.1016/j.phrs.2020.105169] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 08/16/2020] [Accepted: 08/18/2020] [Indexed: 02/07/2023]
Abstract
Atherosclerosis is a multifactorial chronic inflammatory disease of the arterial wall, and an important pathological basis of coronary heart disease. Endothelial cells, vascular smooth muscle cells, and macrophages play important roles in the development of atherosclerosis. Of note, apoptosis and autophagy, two types of programmed cell death, influence the development and progression of atherosclerosis via the modulation of such cells. The small heat shock protein Hsp27 is a multifunctional protein induced by various stress factors and has a protective effect on cells. A large number of studies have demonstrated that Hsp27 plays an important role in regulating apoptosis. Recently, some studies have suggested that Hsp27 also participates in the autophagic process. Moreover, Hsp27 is closely related to the occurrence and development of atherosclerosis. Here, we summarize the molecular mechanisms of apoptosis and autophagy and discuss their effects on endothelial cells, vascular smooth muscle cells, and macrophages in the context of atherosclerotic procession. We further explore the involvement of Hsp27 in apoptosis, autophagy, and atherosclerosis. We speculate that Hsp27 may exert its anti-atherosclerotic role via the regulation of apoptosis and autophagy; this may provide the basis for the development of new approaches for the prevention and treatment of atherosclerosis.
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Affiliation(s)
- Ruiting Shan
- Department of Cardiology, The Second Hospital of Jilin University, Changchun, 130041, China
| | - Ning Liu
- Department of Cardiology, The Second Hospital of Jilin University, Changchun, 130041, China
| | - Youyou Yan
- Department of Cardiology, The Second Hospital of Jilin University, Changchun, 130041, China
| | - Bin Liu
- Department of Cardiology, The Second Hospital of Jilin University, Changchun, 130041, China.
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21
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Joshi P, Bodnya C, Rasmussen ML, Romero-Morales AI, Bright A, Gama V. Modeling the function of BAX and BAK in early human brain development using iPSC-derived systems. Cell Death Dis 2020; 11:808. [PMID: 32978370 PMCID: PMC7519160 DOI: 10.1038/s41419-020-03002-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 09/08/2020] [Accepted: 09/10/2020] [Indexed: 12/27/2022]
Abstract
Intrinsic apoptosis relies on the ability of the BCL-2 family to induce the formation of pores on the outer mitochondrial membrane. Previous studies have shown that both BAX and BAK are essential during murine embryogenesis, and reports in human cancer cell lines identified non-canonical roles for BAX and BAK in mitochondrial fission during apoptosis. BAX and BAK function in human brain development remains elusive due to the lack of appropriate model systems. Here, we generated BAX/BAK double knockout human-induced pluripotent stem cells (hiPSCs), hiPSC-derived neural progenitor cells (hNPCs), neural rosettes, and cerebral organoids to uncover the effects of BAX and BAK deletion in an in vitro model of early human brain development. We found that BAX and BAK-deficient cells have abnormal mitochondrial morphology and give rise to aberrant cortical structures. We suggest crucial functions for BAX and BAK during human development, including maintenance of homeostatic mitochondrial morphology, which is crucial for proper development of progenitors and neurons of the cortex. Human pluripotent stem cell-derived systems can be useful platforms to reveal novel functions of the apoptotic machinery in neural development.
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Affiliation(s)
- Piyush Joshi
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Caroline Bodnya
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Megan L Rasmussen
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | | | - Anna Bright
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Vivian Gama
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA.
- Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, USA.
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22
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Naim S, Kaufmann T. The Multifaceted Roles of the BCL-2 Family Member BOK. Front Cell Dev Biol 2020; 8:574338. [PMID: 33043006 PMCID: PMC7523462 DOI: 10.3389/fcell.2020.574338] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/18/2020] [Indexed: 12/16/2022] Open
Abstract
BCL-2-related ovarian killer (BOK) is-despite its identification over 20 years ago-an incompletely understood member of the BCL-2 family. BCL-2 family proteins are best known for their critical role in the regulation of mitochondrial outer membrane permeabilization during the intrinsic apoptotic pathway. Based on sequence and structural similarities to BAX and BAK, BOK is grouped with these "killers" within the effector subgroup of the family. However, the mechanism of how exactly BOK exerts apoptosis is not clear and controversially discussed. Furthermore, and in accordance with reports on several other BCL-2 family members, BOK seems to be involved in the regulation of a variety of other, "apoptosis-independent" cellular functions, including the unfolded protein response, cellular proliferation, metabolism, and autophagy. Of note, compared with other proapoptotic BCL-2 family members, BOK levels are often reduced in cancer by various means, and there is increasing evidence for BOK modulating tumorigenesis. In this review, we summarize and discuss apoptotic- and non-apoptotic-related functions of BOK, its regulation as well as its physiological and pathophysiological roles.
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Affiliation(s)
- Samara Naim
- Institute of Pharmacology, University of Bern, Bern, Switzerland
| | - Thomas Kaufmann
- Institute of Pharmacology, University of Bern, Bern, Switzerland
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23
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Navarro JF, Croteau DL, Jurek A, Andrusivova Z, Yang B, Wang Y, Ogedegbe B, Riaz T, Støen M, Desler C, Rasmussen LJ, Tønjum T, Galas MC, Lundeberg J, Bohr VA. Spatial Transcriptomics Reveals Genes Associated with Dysregulated Mitochondrial Functions and Stress Signaling in Alzheimer Disease. iScience 2020; 23:101556. [PMID: 33083725 PMCID: PMC7522123 DOI: 10.1016/j.isci.2020.101556] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/24/2020] [Accepted: 09/09/2020] [Indexed: 12/15/2022] Open
Abstract
Alzheimer disease (AD) is a devastating neurological disease associated with progressive loss of mental skills and cognitive and physical functions whose etiology is not completely understood. Here, our goal was to simultaneously uncover novel and known molecular targets in the structured layers of the hippocampus and olfactory bulbs that may contribute to early hippocampal synaptic deficits and olfactory dysfunction in AD mice. Spatially resolved transcriptomics was used to identify high-confidence genes that were differentially regulated in AD mice relative to controls. A diverse set of genes that modulate stress responses and transcription were predominant in both hippocampi and olfactory bulbs. Notably, we identify Bok, implicated in mitochondrial physiology and cell death, as a spatially downregulated gene in the hippocampus of mouse and human AD brains. In summary, we provide a rich resource of spatially differentially expressed genes, which may contribute to understanding AD pathology. Spatial transcriptomics identifies differentially expressed genes with spatial patterns Early application of spatial transcriptomics to olfactory bulbs from AD models Bok gene is spatially differentially expressed in AD mouse and patient brains Paip1 and Homer1 genes are regulated in a PolB-dependent manner
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Affiliation(s)
- José Fernández Navarro
- Science for Life Laboratory, Department of Gene Technology, KTH Royal Institute of Technology, 17165 Stockholm, Sweden
| | - Deborah L Croteau
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Aleksandra Jurek
- Science for Life Laboratory, Department of Gene Technology, KTH Royal Institute of Technology, 17165 Stockholm, Sweden
| | - Zaneta Andrusivova
- Science for Life Laboratory, Department of Gene Technology, KTH Royal Institute of Technology, 17165 Stockholm, Sweden
| | - Beimeng Yang
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Yue Wang
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Benjamin Ogedegbe
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD 21224, USA
| | - Tahira Riaz
- Unit for Genome Dynamics, Department of Microbiology, University of Oslo and Oslo University Hospital, 0372 Oslo, Norway
| | - Mari Støen
- Unit for Genome Dynamics, Department of Microbiology, University of Oslo and Oslo University Hospital, 0372 Oslo, Norway
| | - Claus Desler
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Lene Juel Rasmussen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Tone Tønjum
- Unit for Genome Dynamics, Department of Microbiology, University of Oslo and Oslo University Hospital, 0372 Oslo, Norway
| | - Marie-Christine Galas
- University of Lille, Inserm, CHU Lille, UMR-S 1172 - Centre de Recherche Jean-Pierre AUBERT Neurosciences et Cancer, 59000 Lille, France
| | - Joakim Lundeberg
- Science for Life Laboratory, Department of Gene Technology, KTH Royal Institute of Technology, 17165 Stockholm, Sweden
| | - Vilhelm A Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD 21224, USA.,Unit for Genome Dynamics, Department of Microbiology, University of Oslo and Oslo University Hospital, 0372 Oslo, Norway
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24
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The BCL-2 selective inhibitor ABT-199 sensitizes soft tissue sarcomas to proteasome inhibition by a concerted mechanism requiring BAX and NOXA. Cell Death Dis 2020; 11:701. [PMID: 32839432 PMCID: PMC7445285 DOI: 10.1038/s41419-020-02910-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 02/06/2023]
Abstract
Soft tissue sarcomas (STS) are a heterogeneous group of malignancies predominantly affecting children and young adults. Despite improvements in multimodal therapies, 5-year survival rates are only 50% and new treatment options in STS are urgently needed. To develop a rational combination therapy for the treatment of STS we focused on ABT-199 (Venetoclax), a BCL-2 specific BH3-mimetic, in combination with the proteasome inhibitor bortezomib (BZB). Simultaneous inhibition of BCL-2 and the proteasome resulted in strongly synergistic apoptosis induction. Mechanistically, ABT-199 mainly affected the multidomain effector BAX by liberating it from BCL-2 inhibition. The combination with BZB additionally resulted in the accumulation of BOK, a BAX/BAK homologue, and of the BH3-only protein NOXA, which inhibits the anti-apoptotic protein MCL-1. Thus, the combination of ABT-199 and BZB sensitizes STS cells to apoptosis by simultaneously releasing several defined apoptotic restraints. This synergistic mechanism of action was verified by CRISPR/Cas9 knock-out, showing that both BAX and NOXA are crucial for ABT-199/BZB-induced apoptosis. Noteworthy, efficient induction of apoptosis by ABT-199/BZB was not affected by the p53 status and invariably detected in cell lines and patient-derived tumor cells of several sarcoma types, including rhabdomyo-, leiomyo-, lipo-, chondro-, osteo-, or synovial sarcomas. Hence, we propose the combination of ABT-199 and BZB as a promising strategy for the treatment of STS, which should warrant further clinical investigation.
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Abstract
Apoptosis is a form of programmed cell death that is essential for tissue homeostasis. De-regulation of the balance between proliferation and apoptosis contributes to tumor initiation. Particularly in the colon where apoptosis is a crucial process in intestinal turnover, inhibition of apoptosis facilitates transformation and tumor progression. The BCL-2 family of proteins are key regulators of apoptosis and have been implicated in colorectal cancer (CRC) initiation, progression and resistance to therapy. In this review we outline the current knowledge on the BCL-2 family-regulated intrinsic apoptosis pathway and mechanisms by which it is de-regulated in CRC. We further review BH3 mimetics as a therapeutic opportunity to target this pathway and evaluate their potential for CRC treatment.
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Affiliation(s)
- Prashanthi Ramesh
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Oncode Institute, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Jan Paul Medema
- Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
- Oncode Institute, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
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26
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Lin S, He Y, Gong Y, Zhang Y, Ma H, Zheng H, Li S. SpBOK inhibits WSSV infection by regulating the apoptotic pathway in mud crab (Scylla paramamosain). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 106:103603. [PMID: 31899307 DOI: 10.1016/j.dci.2019.103603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 12/27/2019] [Accepted: 12/28/2019] [Indexed: 06/10/2023]
Abstract
B-cell lymphoma 2 (Bcl-2) related ovarian killer (BOK) is a member of the Bcl-2 family, which has a similar function to BAX and BAK in the process of apoptosis. However, how BOK activates the intrinsic (mitochondrial) apoptotic pathway remains poorly understood in invertebrates. In this study, SpBOK identified in mud crab is an important effector responsible for the anti-WSSV (White Spot Syndrome Virus) infection by activating the apoptotic pathway. The SpBOK gene encoded a 282 amino acid peptides (molecular mass of 29 kD), which contained four distinct Bcl-2 family homology (BH) domains. SpBOK was widely expressed in all tested tissues and up-regulated after WSSV infection in vivo. The role of SpBOK on the anti-WSSV response in mud crab was investigated by using the RNAi approach in vivo. SpBOK exerted a regulatory role in changing the mitochondrial membrane potential (⊿ψm) and activating the caspase signaling and thus induced apoptosis. Moreover, the results showed that WSSV replication in mud crab could be effectively inhibited by SpBOK. Therefore, the results of this study demonstrated that SpBOK can inhibit WSSV infection by regulating the intrinsic apoptosis pathway in mud crab.
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Affiliation(s)
- Shanmeng Lin
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Yuyong He
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Yi Gong
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Yueling Zhang
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Hongyu Ma
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Huaiping Zheng
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China
| | - Shengkang Li
- Guangdong Provincial Key Laboratory of Marine Biology, Shantou University, Shantou, 515063, China; Marine Biology Institute, Shantou University, Shantou, 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, China.
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Moldoveanu T, Czabotar PE. BAX, BAK, and BOK: A Coming of Age for the BCL-2 Family Effector Proteins. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a036319. [PMID: 31570337 DOI: 10.1101/cshperspect.a036319] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The BCL-2 family of proteins control a key checkpoint in apoptosis, that of mitochondrial outer membrane permeabilization or, simply, mitochondrial poration. The family consists of three subgroups: BH3-only initiators that respond to apoptotic stimuli; antiapoptotic guardians that protect against cell death; and the membrane permeabilizing effectors BAX, BAK, and BOK. On activation, effector proteins are converted from inert monomers into membrane permeabilizing oligomers. For many years, this process has been poorly understood at the molecular level, but a number of recent advances have provided important insights. We review the regulation of these effectors, their activation, subsequent conformational changes, and the ensuing oligomerization events that enable mitochondrial poration, which initiates apoptosis through release of key signaling factors such as cytochrome c We highlight the mysteries that remain in understanding these important proteins in an endeavor to provide a comprehensive picture of where the field currently sits and where it is moving toward.
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Affiliation(s)
- Tudor Moldoveanu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.,Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis Tennessee 38105, USA
| | - Peter E Czabotar
- Walter and Eliza Hall Institute of Medical Research, University of Melbourne, Parkville, Victoria 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
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28
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Bock FJ, Tait SWG. Mitochondria as multifaceted regulators of cell death. Nat Rev Mol Cell Biol 2020; 21:85-100. [PMID: 31636403 DOI: 10.1038/s41580-019-0173-8] [Citation(s) in RCA: 1179] [Impact Index Per Article: 294.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2019] [Indexed: 12/12/2022]
Abstract
Through their many and varied metabolic functions, mitochondria power life. Paradoxically, mitochondria also have a central role in apoptotic cell death. Upon induction of mitochondrial apoptosis, mitochondrial outer membrane permeabilization (MOMP) usually commits a cell to die. Apoptotic signalling downstream of MOMP involves cytochrome c release from mitochondria and subsequent caspase activation. As such, targeting MOMP in order to manipulate cell death holds tremendous therapeutic potential across different diseases, including neurodegenerative diseases, autoimmune disorders and cancer. In this Review, we discuss new insights into how mitochondria regulate apoptotic cell death. Surprisingly, recent data demonstrate that besides eliciting caspase activation, MOMP engages various pro-inflammatory signalling functions. As we highlight, together with new findings demonstrating cell survival following MOMP, this pro-inflammatory role suggests that mitochondria-derived signalling downstream of pro-apoptotic cues may also have non-lethal functions. Finally, we discuss the importance and roles of mitochondria in other forms of regulated cell death, including necroptosis, ferroptosis and pyroptosis. Collectively, these new findings offer exciting, unexplored opportunities to target mitochondrial regulation of cell death for clinical benefit.
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Affiliation(s)
- Florian J Bock
- Cancer Research UK Beatson Institute, Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Stephen W G Tait
- Cancer Research UK Beatson Institute, Institute of Cancer Sciences, University of Glasgow, Glasgow, UK.
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29
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Rasmussen ML, Gama V. A connection in life and death: The BCL-2 family coordinates mitochondrial network dynamics and stem cell fate. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 353:255-284. [PMID: 32381177 DOI: 10.1016/bs.ircmb.2019.12.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The B cell CLL/lymphoma-2 (BCL-2) family of proteins control the mitochondrial pathway of apoptosis, also known as intrinsic apoptosis. Direct binding between members of the BCL-2 family regulates mitochondrial outer membrane permeabilization (MOMP) after an apoptotic insult. The ability of the cell to sense stress and translate it into a death signal has been a major theme of research for nearly three decades; however, other mechanisms by which the BCL-2 family coordinates cellular homeostasis beyond its role in initiating apoptosis are emerging. One developing area of research is understanding how the BCL-2 family of proteins regulate development using pluripotent stem cells as a model system. Understanding BCL-2 family-mediated regulation of mitochondrial homeostasis in cell death and beyond would uncover new facets of stem cell maintenance and differentiation potential.
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Affiliation(s)
- Megan L Rasmussen
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, United States
| | - Vivian Gama
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN, United States; Neuroscience Program, Vanderbilt University Medical Center, Nashville, TN, United States; Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, United States; Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States.
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30
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The Bcl-2 Family: Ancient Origins, Conserved Structures, and Divergent Mechanisms. Biomolecules 2020; 10:biom10010128. [PMID: 31940915 PMCID: PMC7022251 DOI: 10.3390/biom10010128] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/18/2019] [Accepted: 01/09/2020] [Indexed: 12/13/2022] Open
Abstract
Intrinsic apoptosis, the response to intracellular cell death stimuli, is regulated by the interplay of the B-cell lymphoma 2 (Bcl-2) family and their membrane interactions. Bcl-2 proteins mediate a number of processes including development, homeostasis, autophagy, and innate and adaptive immune responses and their dysregulation underpins a host of diseases including cancer. The Bcl-2 family is characterized by the presence of conserved sequence motifs called Bcl-2 homology motifs, as well as a transmembrane region, which form the interaction sites and intracellular location mechanism, respectively. Bcl-2 proteins have been recognized in the earliest metazoans including Porifera (sponges), Placozoans, and Cnidarians (e.g., Hydra). A number of viruses have gained Bcl-2 homologs and subvert innate immunity and cellular apoptosis for their replication, but they frequently have very different sequences to their host Bcl-2 analogs. Though most mechanisms of apoptosis initiation converge on activation of caspases that destroy the cell from within, the numerous gene insertions, deletions, and duplications during evolution have led to a divergence in mechanisms of intrinsic apoptosis. Currently, the action of the Bcl-2 family is best understood in vertebrates and nematodes but new insights are emerging from evolutionarily earlier organisms. This review focuses on the mechanisms underpinning the activity of Bcl-2 proteins including their structures and interactions, and how they have changed over the course of evolution.
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31
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Ji Y, Shen J, Li M, Zhu X, Wang Y, Ding J, Jiang S, Chen L, Wei W. RMP/URI inhibits both intrinsic and extrinsic apoptosis through different signaling pathways. Int J Biol Sci 2019; 15:2692-2706. [PMID: 31754340 PMCID: PMC6854365 DOI: 10.7150/ijbs.36829] [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: 05/19/2019] [Accepted: 08/24/2019] [Indexed: 02/06/2023] Open
Abstract
The evading apoptosis of tumor cells may result in chemotherapy resistance. Therefore, investigating what molecular events contribute to drug-induced apoptosis, and how tumors evade apoptotic death, provides a paradigm to explain the relationship between cancer genetics and treatment sensitivity. In this study, we focused on the role of RMP/URI both in cisplatin-induced endogenous apoptosis and in TRAIL-induced exogenous apoptosis in HCC cells. Although flow cytometric analysis indicated that RMP overexpression reduced the apoptosis rate of HCC cells treated with both cisplatin and TRAIL, there was a difference in mechanism between the two treatments. Western blot showed that in intrinsic apoptosis induced by cisplatin, the overexpression of RMP promoted the Bcl-xl expression both in vitro and in vivo. Besides, RMP activated NF-κB/p65(rel) through the phosphorylation of ATM. However, in TRAIL-induced extrinsic apoptosis, RMP significantly suppressed the transcription and expression of P53. Moreover, the forced expression of P53 could offset this inhibitory effect. In conclusion, we presumed that RMP inhibited both intrinsic and extrinsic apoptosis through different signaling pathways. NF-κB was distinctively involved in the RMP circumvention of intrinsic apoptosis, but not in the extrinsic apoptosis of HCC cells. RMP might play an important role in defects of apoptosis, hence the chemotherapeutic resistance in hepatocellular carcinoma. These studies are promising to shed light on a more rational approach to clinical anticancer drug design and therapy.
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Affiliation(s)
- Yuan Ji
- Department of Cell Biology, Institute of Bioengineering, School of Medicine, Soochow University, Suzhou 215123, China
| | - Jian Shen
- Department of Interventional Radiology, First Affiliated Hospital of Soochow University, Suzhou, 215006, China
| | - Min Li
- Department of Tumor, People Hospital of Maanshan, Maanshan, 243000, China
| | - Xiaoxiao Zhu
- Department of Cell Biology, Institute of Bioengineering, School of Medicine, Soochow University, Suzhou 215123, China
| | - Yanyan Wang
- Department of Cell Biology, Institute of Bioengineering, School of Medicine, Soochow University, Suzhou 215123, China
| | - Jiazheng Ding
- Department of Cell Biology, Institute of Bioengineering, School of Medicine, Soochow University, Suzhou 215123, China
| | - Shunyao Jiang
- Department of Cell Biology, Institute of Bioengineering, School of Medicine, Soochow University, Suzhou 215123, China
| | - Linqi Chen
- Department of Endocrinology, Children's Hospital affiliated to Soochow University, Suzhou, 215000, China
| | - Wenxiang Wei
- Department of Cell Biology, Institute of Bioengineering, School of Medicine, Soochow University, Suzhou 215123, China
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健愉 冯, 玉山 朱, 陈 权, 凌 林, Jianyu F, Yushan Z, Quan C, Jialing L. [Physiological Function and Structural Basis of Bcl-2 Family Proteins]. ZHONGGUO XI BAO SHENG WU XUE XUE BAO 2019; 41:1477-1489. [PMID: 34249113 PMCID: PMC8265309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Apoptosis is an important biological process that plays a key role in the regulation of cell fate and homeostasis. The B-cell lymphoma-2 (Bcl-2) family proteins are important regulators of the apoptotic pathway, and their dysfunction is associated with a variety of diseases, including cancer, neurodegenerative and autoimmune diseases. In the past decade, a large number of research work on the physiological functions and atomic structures of Bcl-2 family proteins have been reported, which has deepened our understanding of the molecular mechanism and pathological significance of Bcl-2 family proteins. Recently, new drugs targeting different Bcl-2 proteins have been developed and used in clinics or tested in clinical trials. However, the complexity and diversity in functions and structures of Bcl-2 family have left many unsolved problems. This article summarizes current knowledge of the structure and function of Bcl-2 family proteins and discusses the pharmacological significance of Bcl-2 proteins as effective therapeutic targets.
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Affiliation(s)
| | | | | | - 林家 凌
- 俄克拉荷马大学健康科学中心生物化学与分子生物学系, 俄克拉何马城 73126-0901
| | - Feng Jianyu
- College of Life Sciences, Nankai University, Tianjin 300074, China
| | - Zhu Yushan
- College of Life Sciences, Nankai University, Tianjin 300074, China
| | - Chen Quan
- College of Life Sciences, Nankai University, Tianjin 300074, China
| | - Lin Jialing
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma 73126, USA
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33
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McNamara DE, Dovey CM, Hale AT, Quarato G, Grace CR, Guibao CD, Diep J, Nourse A, Cai CR, Wu H, Kalathur RC, Green DR, York JD, Carette JE, Moldoveanu T. Direct Activation of Human MLKL by a Select Repertoire of Inositol Phosphate Metabolites. Cell Chem Biol 2019; 26:863-877.e7. [PMID: 31031142 DOI: 10.1016/j.chembiol.2019.03.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 02/08/2019] [Accepted: 03/15/2019] [Indexed: 12/29/2022]
Abstract
Necroptosis is an inflammatory form of programmed cell death executed through plasma membrane rupture by the pseudokinase mixed lineage kinase domain-like (MLKL). We previously showed that MLKL activation requires metabolites of the inositol phosphate (IP) pathway. Here we reveal that I(1,3,4,6)P4, I(1,3,4,5,6)P5, and IP6 promote membrane permeabilization by MLKL through directly binding the N-terminal executioner domain (NED) and dissociating its auto-inhibitory region. We show that IP6 and inositol pentakisphosphate 2-kinase (IPPK) are required for necroptosis as IPPK deletion ablated IP6 production and inhibited necroptosis. The NED auto-inhibitory region is more extensive than originally described and single amino acid substitutions along this region induce spontaneous necroptosis by MLKL. Activating IPs bind three sites with affinity of 100-600 μM to destabilize contacts between the auto-inhibitory region and NED, thereby promoting MLKL activation. We therefore uncover MLKL's activating switch in NED triggered by a select repertoire of IP metabolites.
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Affiliation(s)
- Dan E McNamara
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Cole M Dovey
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew T Hale
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Giovanni Quarato
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Christy R Grace
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Cristina D Guibao
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jonathan Diep
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Amanda Nourse
- Molecular Interaction Analysis Shared Resource, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Casey R Cai
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Hong Wu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Ravi C Kalathur
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Douglas R Green
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - John D York
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Jan E Carette
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Tudor Moldoveanu
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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34
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Bok regulates mitochondrial fusion and morphology. Cell Death Differ 2019; 26:2682-2694. [PMID: 30976095 DOI: 10.1038/s41418-019-0327-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 03/05/2019] [Accepted: 03/25/2019] [Indexed: 12/11/2022] Open
Abstract
Bok (Bcl-2-related ovarian killer) is a member of the Bcl-2 protein family that governs the intrinsic apoptosis pathway, but the cellular role that Bok plays is controversial. Remarkably, endogenous Bok is constitutively bound to inositol 1,4,5-trisphosphate receptors (IP3Rs) and is stabilized by this interaction. Here we report that despite the strong association with IP3Rs, deletion of Bok expression by CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein-9 nuclease)-mediated gene editing does not alter calcium mobilization via IP3Rs or calcium influx into the mitochondria. Rather, Bok deletion significantly reduces mitochondrial fusion rate, resulting in mitochondrial fragmentation. This phenotype is reversed by exogenous wild-type Bok and by an IP3R binding-deficient Bok mutant, and may result from a decrease in mitochondrial motility. Bok deletion also enhances mitochondrial spare respiratory capacity and membrane potential. Finally, Bok does not play a major role in apoptotic signaling, since Bok deletion does not alter responsiveness to various apoptotic stimuli. Overall, despite binding to IP3Rs, Bok does not alter IP3R-mediated Ca2+ signaling, but is required to maintain normal mitochondrial fusion, morphology, and bioenergetics.
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35
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Slomp A, Peperzak V. Role and Regulation of Pro-survival BCL-2 Proteins in Multiple Myeloma. Front Oncol 2018; 8:533. [PMID: 30524962 PMCID: PMC6256118 DOI: 10.3389/fonc.2018.00533] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 10/30/2018] [Indexed: 12/12/2022] Open
Abstract
Apoptosis plays a key role in protection against genomic instability and maintaining tissue homeostasis, and also shapes humoral immune responses. During generation of an antibody response, multiple rounds of B-cell expansion and selection take place in germinal centers (GC) before high antigen affinity memory B-cells and long-lived plasma cells (PC) are produced. These processes are tightly regulated by the intrinsic apoptosis pathway, and malignant transformation throughout and following the GC reaction is often characterized by apoptosis resistance. Expression of pro-survival BCL-2 family protein MCL-1 is essential for survival of malignant PC in multiple myeloma (MM). In addition, BCL-2 and BCL-XL contribute to apoptosis resistance. MCL-1, BCL-2, and BCL-XL expression is induced and maintained by signals from the bone marrow microenvironment, but overexpression can also result from genetic lesions. Since MM PC depend on these proteins for survival, inhibiting pro-survival BCL-2 proteins using novel and highly specific BH3-mimetic inhibitors is a promising strategy for treatment. This review addresses the role and regulation of pro-survival BCL-2 family proteins during healthy PC differentiation and in MM, as well as their potential as therapeutic targets.
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Affiliation(s)
- Anne Slomp
- Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Victor Peperzak
- Laboratory of Translational Immunology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
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36
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Fernandez-Marrero Y, Bachmann D, Lauber E, Kaufmann T. Negative Regulation of BOK Expression by Recruitment of TRIM28 to Regulatory Elements in Its 3' Untranslated Region. iScience 2018; 9:461-474. [PMID: 30471638 PMCID: PMC6260365 DOI: 10.1016/j.isci.2018.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/23/2018] [Accepted: 11/01/2018] [Indexed: 02/07/2023] Open
Abstract
BCL-2-related ovarian killer (BOK) is a pro-apoptotic BAX-like member of the BCL-2 family with suggested tumor suppressor activity. The molecular mechanisms regulating BOK expression are poorly understood and fail to explain a frequent lack of concordance between protein and transcript levels. Here, we describe a potent post-transcriptional mechanism that negatively regulates BOK expression mediated by conserved (AU/U)-rich elements within its 3’ UTR. Using proteomics approaches we identified TRIM28 as a key component associating with U-rich elements in the human BOK 3’ UTR, resulting in a dramatic reduction of BOK expression. TRIM28 is overexpressed in several cancers, correlating with poor patient outcome, whereas the BOK locus is frequently deleted or its expression downregulated in human cancers. Data mining indicated that, for certain cancers, high TRIM28 and low BOK expression are significantly correlated in the stratum of patients with the worst survival, suggesting that this mechanism might be of potential therapeutic value. BOK mRNA is destabilized by AU-(mouse) or U-rich (human) elements within its 3’ UTR Mutation of these ARE/URE sequences results in increased BOK RNA and protein levels TRIM28 represses BOK expression by associating with the UREs of human BOK mRNA Inverse correlation of TRIM28 and BOK levels predicts survival in selected cancers
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Affiliation(s)
- Yuniel Fernandez-Marrero
- Institute of Pharmacology, Faculty of Medicine, University of Bern, Inselspital, INO-F, 3010 Bern, Switzerland
| | - Daniel Bachmann
- Institute of Pharmacology, Faculty of Medicine, University of Bern, Inselspital, INO-F, 3010 Bern, Switzerland
| | - Emanuel Lauber
- Institute of Pharmacology, Faculty of Medicine, University of Bern, Inselspital, INO-F, 3010 Bern, Switzerland
| | - Thomas Kaufmann
- Institute of Pharmacology, Faculty of Medicine, University of Bern, Inselspital, INO-F, 3010 Bern, Switzerland.
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37
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Taurine regulates mucosal barrier function to alleviate lipopolysaccharide-induced duodenal inflammation in chicken. Amino Acids 2018; 50:1637-1646. [DOI: 10.1007/s00726-018-2631-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 08/02/2018] [Indexed: 12/15/2022]
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38
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Stehle D, Grimm M, Einsele-Scholz S, Ladwig F, Johänning J, Fischer G, Gillissen B, Schulze-Osthoff K, Essmann F. Contribution of BH3-domain and Transmembrane-domain to the Activity and Interaction of the Pore-forming Bcl-2 Proteins Bok, Bak, and Bax. Sci Rep 2018; 8:12434. [PMID: 30127460 PMCID: PMC6102298 DOI: 10.1038/s41598-018-30603-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 08/02/2018] [Indexed: 12/15/2022] Open
Abstract
Central to intrinsic apoptosis signaling is the release of cytochrome c from mitochondria, which depends on the pro-apoptotic effector proteins Bax, Bak or Bok. These pore-forming effector proteins share four Bcl-2 homology (BH) domains, a functionally essential and conserved sequence of hydrophobic amino acids in their BH3-domain and a C-terminal transmembrane-domain whose specific function remains rather unknown. To elucidate the molecular basis of Bok-mediated apoptosis we analyzed apoptosis induction by transmembrane-domain deficient BokΔTM compared to the respective Bax and Bak proteins and proteins in which the first leucine in the BH3-stretch was mutated to glutamic acid. We show that deletion of the C-terminal transmembrane-domain reduces the pro-apoptotic function of each protein. Mutation of the first leucine in the BH3-domain (L78E) blocks activity of Bak, while mutation of the homologue residues in Bax or Bok (L63E and L70E respectively) does not affect apoptosis induction. Unexpectedly, combined mutation of the BH3-domain and deletion of the transmembrane-domain enhances the pro-apoptotic activity of Bok(L70E)ΔTM by abolishing the interaction with anti-apoptotic proteins, especially the primary Bok-inhibitory protein Mcl-1. These results therefore suggest a specific contribution of the transmembrane-domain to the pro-apoptotic function and interaction of Bok.
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Affiliation(s)
- Daniel Stehle
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076, Tübingen, Germany
| | - Melanie Grimm
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076, Tübingen, Germany
| | - Stephanie Einsele-Scholz
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076, Tübingen, Germany
| | - Friederike Ladwig
- Department of Plant Physiology, Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076, Tübingen, Germany
| | - Janina Johänning
- Dr. Margarete Fischer-Bosch Institute for Clinical Pharmacology (IKP), 70376, Stuttgart, Germany
| | - Gerd Fischer
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076, Tübingen, Germany
| | - Bernhard Gillissen
- Clinical and Molecular Oncology, University Medical Center Charité, 13125, Berlin, Germany
| | - Klaus Schulze-Osthoff
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076, Tübingen, Germany.,German Cancer Consortium (DKTK) and German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
| | - Frank Essmann
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, University of Tübingen, 72076, Tübingen, Germany.
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39
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Moldoveanu T, Zheng JH. Metastability, an emerging concept governing BOK-mediated apoptosis initiation. Oncotarget 2018; 9:30944-30945. [PMID: 30123418 PMCID: PMC6089559 DOI: 10.18632/oncotarget.25801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 07/12/2018] [Indexed: 11/25/2022] Open
Affiliation(s)
- Tudor Moldoveanu
- Tudor Moldoveanu: Departments of Structural Biology & Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Janet H Zheng
- Tudor Moldoveanu: Departments of Structural Biology & Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
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