1
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Ortiz HR, Cruz Flores P, Podgorski J, Ramonett A, Ahmed T, Hempel N, Charest PG, Ellis NA, Langlais PR, Montfort WR, Mythreye K, Kumar S, Lee NY. Extracellular signals induce dynamic ER remodeling through αTAT1-dependent microtubule acetylation. Neoplasia 2024; 53:101003. [PMID: 38759377 PMCID: PMC11127537 DOI: 10.1016/j.neo.2024.101003] [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: 04/22/2024] [Accepted: 04/26/2024] [Indexed: 05/19/2024]
Abstract
Dynamic changes in the endoplasmic reticulum (ER) morphology are central to maintaining cellular homeostasis. Microtubules (MT) facilitate the continuous remodeling of the ER network into sheets and tubules by coordinating with many ER-shaping protein complexes, although how this process is controlled by extracellular signals remains unknown. Here we report that TAK1, a kinase responsive to various growth factors and cytokines including TGF-β and TNF-α, triggers ER tubulation by activating αTAT1, an MT-acetylating enzyme that enhances ER-sliding. We show that this TAK1/αTAT1-dependent ER remodeling promotes cell survival by actively downregulating BOK, an ER membrane-associated proapoptotic effector. While BOK is normally protected from degradation when complexed with IP3R, it is rapidly degraded upon their dissociation during the ER sheets-to-tubules conversion. These findings demonstrate a distinct mechanism of ligand-induced ER remodeling and suggest that the TAK1/αTAT1 pathway may be a key target in ER stress and dysfunction.
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Affiliation(s)
- Hannah R Ortiz
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724, USA
| | - Paola Cruz Flores
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85724, USA
| | - Julia Podgorski
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724, USA
| | - Aaron Ramonett
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724, USA
| | - Tasmia Ahmed
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85724, USA
| | - Nadine Hempel
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Pascale G Charest
- Department of Molecular & Cellular Biology, University of Arizona, Tucson, AZ 85724, USA
| | - Nathan A Ellis
- Department of Cellular & Molecular Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Paul R Langlais
- Department of Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - William R Montfort
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85724, USA
| | | | - Sanjay Kumar
- Division of Biology, Indian Institute of Science Education & Research Tirupati, Mangalam Tirupati 517507, India.
| | - Nam Y Lee
- Department of Pharmacology, University of Arizona, Tucson, AZ 85724, USA; Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85724, USA; Comprehensive Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
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2
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Cauwelier C, de Ridder I, Bultynck G. Recent advances in canonical versus non-canonical Ca 2+-signaling-related anti-apoptotic Bcl-2 functions and prospects for cancer treatment. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119713. [PMID: 38521468 DOI: 10.1016/j.bbamcr.2024.119713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 01/11/2024] [Accepted: 03/20/2024] [Indexed: 03/25/2024]
Abstract
Cell fate is tightly controlled by a continuous balance between cell survival and cell death inducing mechanisms. B-cell lymphoma 2 (Bcl-2)-family members, composed of effectors and regulators, not only control apoptosis at the level of the mitochondria but also by impacting the intracellular Ca2+ homeostasis and dynamics. On the one hand, anti-apoptotic protein Bcl-2, prevents mitochondrial outer membrane permeabilization (MOMP) by scaffolding and neutralizing proapoptotic Bcl-2-family members via its hydrophobic cleft (region composed of BH-domain 1-3). On the other hand, Bcl-2 suppress pro-apoptotic Ca2+ signals by binding and inhibiting IP3 receptors via its BH4 domain, which is structurally exiled from the hydrophobic cleft by a flexible loop region (FLR). As such, Bcl-2 prevents excessive Ca2+ transfer from ER to mitochondria. Whereas regulation of both pathways requires different functional regions of Bcl-2, both seem to be connected in cancers that overexpress Bcl-2 in a life-promoting dependent manner. Here we discuss the anti-apoptotic canonical and non-canonical role, via calcium signaling, of Bcl-2 in health and cancer and evolving from this the proposed anti-cancer therapies with their shortcomings. We also argue how some cancers, with the major focus on diffuse large B-cell lymphoma (DLBCL) are difficult to treat, although theoretically prime marked for Bcl-2-targeting therapeutics. Further work is needed to understand the non-canonical functions of Bcl-2 also at organelles beyond the mitochondria, the interaction partners outside the Bcl-2 family as well as their ability to target or exploit these functions as therapeutic strategies in diseases.
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Affiliation(s)
- Claire Cauwelier
- KU Leuven, Lab. Molecular & Cellular Signaling, Dep. Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Ian de Ridder
- KU Leuven, Lab. Molecular & Cellular Signaling, Dep. Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Lab. Molecular & Cellular Signaling, Dep. Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
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3
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Suraweera CD, Espinoza B, Hinds MG, Kvansakul M. Mastering Death: The Roles of Viral Bcl-2 in dsDNA Viruses. Viruses 2024; 16:879. [PMID: 38932171 PMCID: PMC11209288 DOI: 10.3390/v16060879] [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: 05/07/2024] [Revised: 05/25/2024] [Accepted: 05/27/2024] [Indexed: 06/28/2024] Open
Abstract
Proteins of the Bcl-2 family regulate cellular fate via multiple mechanisms including apoptosis, autophagy, senescence, metabolism, inflammation, redox homeostasis, and calcium flux. There are several regulated cell death (RCD) pathways, including apoptosis and autophagy, that use distinct molecular mechanisms to elicit the death response. However, the same proteins/genes may be deployed in multiple biochemical pathways. In apoptosis, Bcl-2 proteins control the integrity of the mitochondrial outer membrane (MOM) by regulating the formation of pores in the MOM and apoptotic cell death. A number of prosurvival genes populate the genomes of viruses including those of the pro-survival Bcl-2 family. Viral Bcl-2 proteins are sequence and structural homologs of their cellular counterparts and interact with cellular proteins in apoptotic and autophagic pathways, potentially allowing them to modulate these pathways and determine cellular fate.
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Affiliation(s)
- Chathura D. Suraweera
- Genome Sciences and Cancer Division, The John Curtin School of Medical Research, Australian National University, Canberra 2601, Australia;
| | - Benjamin Espinoza
- Department of Biochemistry and Chemistry, La Trobe University, Melbourne, VIC 3086, Australia;
| | - Mark G. Hinds
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Marc Kvansakul
- Genome Sciences and Cancer Division, The John Curtin School of Medical Research, Australian National University, Canberra 2601, Australia;
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4
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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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5
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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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6
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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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7
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Dhaouadi N, Vitto VAM, Pinton P, Galluzzi L, Marchi S. Ca 2+ signaling and cell death. Cell Calcium 2023; 113:102759. [PMID: 37210868 DOI: 10.1016/j.ceca.2023.102759] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/12/2023] [Accepted: 05/13/2023] [Indexed: 05/23/2023]
Abstract
Multiple forms of regulated cell death (RCD) have been characterized, each of which originates from the activation of a dedicated molecular machinery. RCD can occur in purely physiological settings or upon failing cellular adaptation to stress. Ca2+ions have been shown to physically interact with - and hence regulate - various components of the RCD machinery. Moreover, intracellular Ca2+ accumulation can promote organellar dysfunction to degree that can be overtly cytotoxic or sensitize cells to RCD elicited by other stressors. Here, we provide an overview of the main links between Ca2+and different forms of RCD, including apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, lysosome-dependent cell death, and parthanatos.
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Affiliation(s)
- Nada Dhaouadi
- Department of Clinical and Molecular Sciences, Marche Polytechnic University, Ancona, Italy
| | | | - Paolo Pinton
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy; GVM Care & Research, Maria Cecilia Hospital, Cotignola, Italy
| | - Lorenzo Galluzzi
- Department of Radiation Oncology, Weill Cornell Medical College, New York, NY, USA; Sandra and Edward Meyer Cancer Center, New York, NY, USA; Caryl and Israel Englander Institute for Precision Medicine, New York, NY, USA.
| | - Saverio Marchi
- Department of Clinical and Molecular Sciences, Marche Polytechnic University, Ancona, Italy.
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8
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de Ridder I, Kerkhofs M, Lemos FO, Loncke J, Bultynck G, Parys JB. The ER-mitochondria interface, where Ca 2+ and cell death meet. Cell Calcium 2023; 112:102743. [PMID: 37126911 DOI: 10.1016/j.ceca.2023.102743] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 04/20/2023] [Accepted: 04/24/2023] [Indexed: 05/03/2023]
Abstract
Endoplasmic reticulum (ER)-mitochondria contact sites are crucial to allow Ca2+ flux between them and a plethora of proteins participate in tethering both organelles together. Inositol 1,4,5-trisphosphate receptors (IP3Rs) play a pivotal role at such contact sites, participating in both ER-mitochondria tethering and as Ca2+-transport system that delivers Ca2+ from the ER towards mitochondria. At the ER-mitochondria contact sites, the IP3Rs function as a multi-protein complex linked to the voltage-dependent anion channel 1 (VDAC1) in the outer mitochondrial membrane, via the chaperone glucose-regulated protein 75 (GRP75). This IP3R-GRP75-VDAC1 complex supports the efficient transfer of Ca2+ from the ER into the mitochondrial intermembrane space, from which the Ca2+ ions can reach the mitochondrial matrix through the mitochondrial calcium uniporter. Under physiological conditions, basal Ca2+ oscillations deliver Ca2+ to the mitochondrial matrix, thereby stimulating mitochondrial oxidative metabolism. However, when mitochondrial Ca2+ overload occurs, the increase in [Ca2+] will induce the opening of the mitochondrial permeability transition pore, thereby provoking cell death. The IP3R-GRP75-VDAC1 complex forms a hub for several other proteins that stabilize the complex and/or regulate the complex's ability to channel Ca2+ into the mitochondria. These proteins and their mechanisms of action are discussed in the present review with special attention for their role in pathological conditions and potential implication for therapeutic strategies.
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Affiliation(s)
- Ian de Ridder
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, Leuven BE-3000, Belgium
| | - Martijn Kerkhofs
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, Leuven BE-3000, Belgium
| | - Fernanda O Lemos
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, Leuven BE-3000, Belgium
| | - Jens Loncke
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, Leuven BE-3000, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, Leuven BE-3000, Belgium.
| | - Jan B Parys
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, Leuven BE-3000, Belgium.
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9
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Ortiz HR, Flores PC, Ramonett A, Ahmed T, Ellis NA, Langlais PR, Mythreye K, Lee NY. Structural remodeling of the endoplasmic reticulum in response to extracellular signals requires αTAT1-induced microtubule acetylation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.20.537623. [PMID: 37131821 PMCID: PMC10153279 DOI: 10.1101/2023.04.20.537623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Dynamic changes in the endoplasmic reticulum (ER) morphology are central to maintaining cellular homeostasis. Microtubules (MT) facilitate the continuous remodeling of the ER network into sheets and tubules by coordinating with many ER-shaping protein complexes, although how this process is controlled by extracellular signals remains unknown. Here we report that TAK1, a kinase responsive to numerous growth factors and cytokines including TGF-β and TNF-α, triggers ER tubulation by activating αTAT1, an MT-acetylating enzyme that enhances ER-sliding. We show that this TAK1/αTAT-dependent ER remodeling promotes cell survival by actively downregulating BOK, an ER membrane-associated proapoptotic effector. While BOK is normally protected from degradation when complexed with IP3R, it is rapidly degraded upon their dissociation during the ER sheets-to-tubules conversion. These findings demonstrate a distinct mechanism of ligand-induced ER remodeling and suggest that the TAK1/αTAT pathway may be a key target in ER stress and dysfunction.
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10
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Zheng S, Wang X, Zhao D, Liu H, Hu Y. Calcium homeostasis and cancer: insights from endoplasmic reticulum-centered organelle communications. Trends Cell Biol 2023; 33:312-323. [PMID: 35915027 DOI: 10.1016/j.tcb.2022.07.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 12/17/2022]
Abstract
Calcium ion (Ca2+) is a ubiquitous and versatile signaling molecule controlling a wide variety of cellular processes, such as proliferation, cell death, migration, and immune response, all fundamental processes essential for the establishment of cancer. In recent decades, the loss of Ca2+ homeostasis has been considered an important driving force in the initiation and progression of malignant diseases. The primary intracellular Ca2+ store, the endoplasmic reticulum (ER), plays an essential role in maintaining Ca2+ homeostasis by coordinating with other organelles and the plasma membrane. Here, we discuss the dysregulation of ER-centered Ca2+ homeostasis in cancer, summarize Ca2+-based anticancer therapeutics, and highlight the significance of furthering our understanding of Ca2+ homeostasis regulation in cancer.
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Affiliation(s)
- Shanliang Zheng
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang Province 150001, China
| | - Xingwen Wang
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang Province 150001, China
| | - Dong Zhao
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang Province 150001, China
| | - Hao Liu
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang Province 150001, China
| | - Ying Hu
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang Province 150001, China.
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11
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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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12
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Hu Z, Shi S, Ou Y, Hu F, Long D. Mitochondria-associated endoplasmic reticulum membranes: A promising toxicity regulation target. Acta Histochem 2023; 125:152000. [PMID: 36696877 DOI: 10.1016/j.acthis.2023.152000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/15/2023] [Accepted: 01/16/2023] [Indexed: 01/24/2023]
Abstract
Mitochondria-associated endoplasmic reticulum membranes (MAMs) are dynamic suborganelle membranes that physically couple endoplasmic reticulum (ER) and mitochondria to provide a platform for exchange of intracellular molecules and crosstalk between the two organelles. Dysfunctions of mitochondria and ER and imbalance of intracellular homeostasis have been discovered in the research of toxics. Cellular activities such as oxidative stress, ER stress, Ca2+ transport, autophagy, mitochondrial fusion and fission, and apoptosis mediated by MAMs are closely related to the toxicological effects of various toxicants. These cellular activities mediated by MAMs crosstalk with each other. Regulating the structure and function of MAMs can alleviate the damage caused by toxicants to some extent. In this review, we discuss the relationships between MAMs and the mechanisms of toxicological effects, and highlight MAMs as a potential target for protection against toxicants.
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Affiliation(s)
- Zehui Hu
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China
| | - Shengyuan Shi
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China
| | - Yiquan Ou
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China
| | - Fangyan Hu
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China
| | - Dingxin Long
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China.
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13
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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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14
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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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15
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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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16
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Milani M, Pihán P, Hetz C. Mitochondria-associated niches in health and disease. J Cell Sci 2022; 135:285141. [DOI: 10.1242/jcs.259634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
ABSTRACT
The appreciation of the importance of interorganelle contacts has steadily increased over the past decades. Advances in imaging, molecular biology and bioinformatic techniques allowed the discovery of new mechanisms involved in the interaction and communication between organelles, providing novel insights into the inner works of a cell. In this Review, with the mitochondria under the spotlight, we discuss the most recent findings on the mechanisms mediating the communication between organelles, focusing on Ca2+ signaling, lipid exchange, cell death and stress responses. Notably, we introduce a new integrative perspective to signaling networks that is regulated by interorganelle interactions – the mitochondria-associated niches – focusing on the link between the molecular determinants of contact sites and their functional outputs, rather than simply physical and structural communication. In addition, we highlight the neuropathological and metabolic implications of alterations in mitochondria-associated niches and outline how this concept might improve our understanding of multi-organelle interactions.
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Affiliation(s)
- Mateus Milani
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile 1 , Santiago 8380000 , Chile
- FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO) 2 , Santiago 7750000 , Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile 3 , Santiago 8380000 , Chile
| | - Philippe Pihán
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile 1 , Santiago 8380000 , Chile
- FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO) 2 , Santiago 7750000 , Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile 3 , Santiago 8380000 , Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile 1 , Santiago 8380000 , Chile
- FONDAP Center for Geroscience, Brain Health, and Metabolism (GERO) 2 , Santiago 7750000 , Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile 3 , Santiago 8380000 , Chile
- Buck Institute for Research on Aging 4 , Novato, CA 94945 , USA
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17
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Means RE, Katz SG. Balancing life and death: BCL-2 family members at diverse ER-mitochondrial contact sites. FEBS J 2022; 289:7075-7112. [PMID: 34668625 DOI: 10.1111/febs.16241] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/11/2021] [Accepted: 10/19/2021] [Indexed: 01/13/2023]
Abstract
The outer mitochondrial membrane is a busy place. One essential activity for cellular survival is the regulation of membrane integrity by the BCL-2 family of proteins. Another critical facet of the outer mitochondrial membrane is its close approximation with the endoplasmic reticulum. These mitochondrial-associated membranes (MAMs) occupy a significant fraction of the mitochondrial surface and serve as key signaling hubs for multiple cellular processes. Each of these pathways may be considered as forming their own specialized MAM subtype. Interestingly, like membrane permeabilization, most of these pathways play critical roles in regulating cellular survival and death. Recently, the pro-apoptotic BCL-2 family member BOK has been found within MAMs where it plays important roles in their structure and function. This has led to a greater appreciation that multiple BCL-2 family proteins, which are known to participate in numerous functions throughout the cell, also have roles within MAMs. In this review, we evaluate several MAM subsets, their role in cellular homeostasis, and the contribution of BCL-2 family members to their functions.
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Affiliation(s)
- Robert E Means
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
| | - Samuel G Katz
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA
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18
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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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19
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Dadsena S, King LE, García-Sáez AJ. Apoptosis regulation at the mitochondria membrane level. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183716. [PMID: 34343535 DOI: 10.1016/j.bbamem.2021.183716] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 02/05/2023]
Abstract
Mitochondrial outer membrane permeabilization (MOMP) is a key checkpoint in apoptosis that activates the caspase cascade and irreversibly causes the majority of cells to die. The proteins of the Bcl-2 family are master regulators of apoptosis that form a complex interaction network within the mitochondrial membrane that determines the induction of MOMP. This culminates in the activation of the effector members Bax and Bak, which permeabilize the mitochondrial outer membrane to mediate MOMP. Although the key role of Bax and Bak has been established, many questions remain unresolved regarding molecular mechanisms that control the apoptotic pore. In this review, we discuss the recent progress in our understanding of the regulation of Bax/Bak activity within the mitochondrial membrane.
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Affiliation(s)
- Shashank Dadsena
- Institute for Genetics, CECAD Research Center, University of Cologne, Germany
| | - Louise E King
- Institute for Genetics, CECAD Research Center, University of Cologne, Germany
| | - Ana J García-Sáez
- Institute for Genetics, CECAD Research Center, University of Cologne, Germany.
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20
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Szczesniak LM, Bonzerato CG, Wojcikiewicz RJH. Identification of the Bok Interactome Using Proximity Labeling. Front Cell Dev Biol 2021; 9:689951. [PMID: 34136494 PMCID: PMC8201613 DOI: 10.3389/fcell.2021.689951] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/06/2021] [Indexed: 12/28/2022] Open
Abstract
The function of the Bcl-2 family member Bok is currently enigmatic, with various disparate roles reported, including mediation of apoptosis, regulation of mitochondrial morphology, binding to inositol 1,4,5-trisphosphate receptors, and regulation of uridine metabolism. To better define the roles of Bok, we examined its interactome using TurboID-mediated proximity labeling in HeLa cells, in which Bok knock-out leads to mitochondrial fragmentation and Bok overexpression leads to apoptosis. Labeling with TurboID-Bok revealed that Bok was proximal to a wide array of proteins, particularly those involved in mitochondrial fission (e.g., Drp1), endoplasmic reticulum-plasma membrane junctions (e.g., Stim1), and surprisingly among the Bcl-2 family members, just Mcl-1. Comparison with TurboID-Mcl-1 and TurboID-Bak revealed that the three Bcl-2 family member interactomes were largely independent, but with some overlap that likely identifies key interactors. Interestingly, when overexpressed, Mcl-1 and Bok interact physically and functionally, in a manner that depends upon the transmembrane domain of Bok. Overall, this work shows that the Bok interactome is different from those of Mcl-1 and Bak, identifies novel proximities and potential interaction points for Bcl-2 family members, and suggests that Bok may regulate mitochondrial fission via Mcl-1 and Drp1.
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21
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Intrinsically Connected: Therapeutically Targeting the Cathepsin Proteases and the Bcl-2 Family of Protein Substrates as Co-regulators of Apoptosis. Int J Mol Sci 2021; 22:ijms22094669. [PMID: 33925117 PMCID: PMC8124540 DOI: 10.3390/ijms22094669] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 12/14/2022] Open
Abstract
Taken with the growing importance of cathepsin-mediated substrate proteolysis in tumor biology and progression, the focus and emphasis placed on therapeutic design and development is coming into fruition. Underpinning this approach is the invariable progression from the direction of fully characterizing cathepsin protease members and their substrate targets, towards targeting such an interaction with tangible therapeutics. The two groups of such substrates that have gained much attention over the years are the pro- and anti- apoptotic protein intermediates from the extrinsic and intrinsic signaling arms of the apoptosis pathway. As proteins that are central to determining cellular fate, some of them present themselves as very favorable candidates for therapeutic targeting. However, considering that both anti- and pro- apoptotic signaling intermediates have been reported to be downstream substrates for certain activated cathepsin proteases, therapeutic targeting approaches based on greater selectivity do need to be given greater consideration. Herein, we review the relationships shared by the cathepsin proteases and the Bcl-2 homology domain proteins, in the context of how the topical approach of adopting 'BH3-mimetics' can be explored further in modulating the relationship between the anti- and pro- apoptotic signaling intermediates from the intrinsic apoptosis pathway and their upstream cathepsin protease regulators. Based on this, we highlight important future considerations for improved therapeutic design.
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22
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Bcl-2 Family of Proteins in the Control of Mitochondrial Calcium Signalling: An Old Chap with New Roles. Int J Mol Sci 2021; 22:ijms22073730. [PMID: 33918511 PMCID: PMC8038216 DOI: 10.3390/ijms22073730] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 12/12/2022] Open
Abstract
Bcl-2 family proteins are considered as one of the major regulators of apoptosis. Indeed, this family is known to control the mitochondrial outer membrane permeabilization (MOMP): a central step in the mitochondrial pathway of apoptosis. However, in recent years Bcl-2 family members began to emerge as a new class of intracellular calcium (Ca2+) regulators. At mitochondria-ER contacts (MERCs) these proteins are able to interact with major Ca2+ transporters, thus controlling mitochondrial Ca2+ homeostasis and downstream Ca2+ signalling pathways. Beyond the regulation of cell survival, this Bcl-2-dependent control over the mitochondrial Ca2+ dynamics has far-reaching consequences on the physiology of the cell. Here, we review how the Bcl-2 family of proteins mechanistically regulate mitochondrial Ca2+ homeostasis and how this regulation orchestrates cell death/survival decisions as well as the non-apoptotic process of cell migration.
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23
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Lemos FO, Bultynck G, Parys JB. A comprehensive overview of the complex world of the endo- and sarcoplasmic reticulum Ca 2+-leak channels. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119020. [PMID: 33798602 DOI: 10.1016/j.bbamcr.2021.119020] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/09/2021] [Accepted: 03/13/2021] [Indexed: 12/11/2022]
Abstract
Inside cells, the endoplasmic reticulum (ER) forms the largest Ca2+ store. Ca2+ is actively pumped by the SERCA pumps in the ER, where intraluminal Ca2+-binding proteins enable the accumulation of large amount of Ca2+. IP3 receptors and the ryanodine receptors mediate the release of Ca2+ in a controlled way, thereby evoking complex spatio-temporal signals in the cell. The steady state Ca2+ concentration in the ER of about 500 μM results from the balance between SERCA-mediated Ca2+ uptake and the passive leakage of Ca2+. The passive Ca2+ leak from the ER is often ignored, but can play an important physiological role, depending on the cellular context. Moreover, excessive Ca2+ leakage significantly lowers the amount of Ca2+ stored in the ER compared to normal conditions, thereby limiting the possibility to evoke Ca2+ signals and/or causing ER stress, leading to pathological consequences. The so-called Ca2+-leak channels responsible for Ca2+ leakage from the ER are however still not well understood, despite over 20 different proteins have been proposed to contribute to it. This review has the aim to critically evaluate the available evidence about the various channels potentially involved and to draw conclusions about their relative importance.
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Affiliation(s)
- Fernanda O Lemos
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, B-3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, B-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, B-3000 Leuven, Belgium.
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24
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Giamogante F, Poggio E, Barazzuol L, Covallero A, Calì T. Apoptotic signals at the endoplasmic reticulum-mitochondria interface. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 126:307-343. [PMID: 34090618 DOI: 10.1016/bs.apcsb.2021.02.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The maintenance of cellular homeostasis involves the participation of multiple organelles, such as the endoplasmic reticulum (ER) and mitochondria. Specifically, ER plays a key role in calcium (Ca2+) storage, lipid synthesis, protein folding, and assembly, while mitochondria are the "energy factories" and provide energy to drive intracellular processes. Hence, alteration in ER or mitochondrial homeostasis has detrimental effects on cell survival, being linked to the triggering of apoptosis, a programmed form of cell death. Besides, ER stress conditions affect mitochondria functionality and vice-versa, as ER and mitochondria communicate via mitochondria-associated ER membranes (MAMs) to carry out a number of fundamental cellular functions. It is not surprising, thus, that also MAMs perturbations are involved in the regulation of apoptosis. This chapter intends to accurately discuss the involvement of MAMs in apoptosis, highlighting their crucial role in controlling this delicate cellular process.
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Affiliation(s)
- Flavia Giamogante
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Elena Poggio
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Alberto Covallero
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
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25
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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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26
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Wang N, Wang C, Zhao H, He Y, Lan B, Sun L, Gao Y. The MAMs Structure and Its Role in Cell Death. Cells 2021; 10:cells10030657. [PMID: 33809551 PMCID: PMC7999768 DOI: 10.3390/cells10030657] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 02/06/2023] Open
Abstract
The maintenance of cellular homeostasis involves the participation of multiple organelles. These organelles are associated in space and time, and either cooperate or antagonize each other with regards to cell function. Crosstalk between organelles has become a significant topic in research over recent decades. We believe that signal transduction between organelles, especially the endoplasmic reticulum (ER) and mitochondria, is a factor that can influence the cell fate. As the cellular center for protein folding and modification, the endoplasmic reticulum can influence a range of physiological processes by regulating the quantity and quality of proteins. Mitochondria, as the cellular "energy factory," are also involved in cell death processes. Some researchers regard the ER as the sensor of cellular stress and the mitochondria as an important actuator of the stress response. The scientific community now believe that bidirectional communication between the ER and the mitochondria can influence cell death. Recent studies revealed that the death signals can shuttle between the two organelles. Mitochondria-associated membranes (MAMs) play a vital role in the complex crosstalk between the ER and mitochondria. MAMs are known to play an important role in lipid synthesis, the regulation of Ca2+ homeostasis, the coordination of ER-mitochondrial function, and the transduction of death signals between the ER and the mitochondria. Clarifying the structure and function of MAMs will provide new concepts for studying the pathological mechanisms associated with neurodegenerative diseases, aging, and cancers. Here, we review the recent studies of the structure and function of MAMs and its roles involved in cell death, especially in apoptosis.
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Affiliation(s)
- Nan Wang
- China Japan Union Hospital, Jilin University, Changchun 130031, China; (N.W.); (C.W.); (H.Z.); (Y.H.); (B.L.)
| | - Chong Wang
- China Japan Union Hospital, Jilin University, Changchun 130031, China; (N.W.); (C.W.); (H.Z.); (Y.H.); (B.L.)
| | - Hongyang Zhao
- China Japan Union Hospital, Jilin University, Changchun 130031, China; (N.W.); (C.W.); (H.Z.); (Y.H.); (B.L.)
| | - Yichun He
- China Japan Union Hospital, Jilin University, Changchun 130031, China; (N.W.); (C.W.); (H.Z.); (Y.H.); (B.L.)
| | - Beiwu Lan
- China Japan Union Hospital, Jilin University, Changchun 130031, China; (N.W.); (C.W.); (H.Z.); (Y.H.); (B.L.)
| | - Liankun Sun
- Key Laboratory of Pathobiology, Ministry of Education, Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, Changchun 130012, China
- Correspondence: (L.S.); (Y.G.)
| | - Yufei Gao
- China Japan Union Hospital, Jilin University, Changchun 130031, China; (N.W.); (C.W.); (H.Z.); (Y.H.); (B.L.)
- Correspondence: (L.S.); (Y.G.)
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27
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Callens M, Kraskovskaya N, Derevtsova K, Annaert W, Bultynck G, Bezprozvanny I, Vervliet T. The role of Bcl-2 proteins in modulating neuronal Ca 2+ signaling in health and in Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:118997. [PMID: 33711363 DOI: 10.1016/j.bbamcr.2021.118997] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/23/2021] [Accepted: 02/25/2021] [Indexed: 12/11/2022]
Abstract
The family of B-cell lymphoma-2 (Bcl-2) proteins exerts key functions in cellular health. Bcl-2 primarily acts in mitochondria where it controls the initiation of apoptosis. However, during the last decades, it has become clear that this family of proteins is also involved in controlling intracellular Ca2+ signaling, a critical process for the function of most cell types, including neurons. Several anti- and pro-apoptotic Bcl-2 family members are expressed in neurons and impact neuronal function. Importantly, expression levels of neuronal Bcl-2 proteins are affected by age. In this review, we focus on the emerging roles of Bcl-2 proteins in neuronal cells. Specifically, we discuss how their dysregulation contributes to the onset, development, and progression of neurodegeneration in the context of Alzheimer's disease (AD). Aberrant Ca2+ signaling plays an important role in the pathogenesis of AD, and we propose that dysregulation of the Bcl-2-Ca2+ signaling axis may contribute to the progression of AD and that herein, Bcl-2 may constitute a potential therapeutic target for the treatment of AD.
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Affiliation(s)
- Manon Callens
- KU Leuven, Laboratory of Molecular & Cellular Signaling, Department of Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Nina Kraskovskaya
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg State Polytechnic University, Saint Petersburg, Russia
| | - Kristina Derevtsova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg State Polytechnic University, Saint Petersburg, Russia
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB Center for Brain and Disease Research & KU Leuven, Department of Neurosciences, Gasthuisberg, O&N5, Rm 7.357, B-3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular & Cellular Signaling, Department of Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
| | - Ilya Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg State Polytechnic University, Saint Petersburg, Russia; Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX, United States.
| | - Tim Vervliet
- KU Leuven, Laboratory of Molecular & Cellular Signaling, Department of Cellular & Molecular Medicine, Campus Gasthuisberg O/N-I bus 802, Herestraat 49, BE-3000 Leuven, Belgium
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28
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Balancing ER-Mitochondrial Ca 2+ Fluxes in Health and Disease. Trends Cell Biol 2021; 31:598-612. [PMID: 33678551 DOI: 10.1016/j.tcb.2021.02.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/29/2021] [Accepted: 02/02/2021] [Indexed: 02/08/2023]
Abstract
Organelles cooperate with each other to control cellular homeostasis and cell functions by forming close connections through membrane contact sites. Important contacts are present between the endoplasmic reticulum (ER), the main intracellular Ca2+-storage organelle, and the mitochondria, the organelle responsible not only for the majority of cellular ATP production but also for switching on cell death processes. Several Ca2+-transport systems focalize at these contact sites, thereby enabling the efficient transmission of Ca2+ signals from the ER toward mitochondria. This provides tight control of mitochondrial functions at the microdomain level. Here, we discuss how ER-mitochondrial Ca2+ transfers support cell function and how their dysregulation underlies, drives, or contributes to pathogenesis and pathophysiology, with a major focus on cancer and neurodegeneration but also with attention to other diseases such as diabetes and rare genetic diseases.
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Carpio MA, Means RE, Brill AL, Sainz A, Ehrlich BE, Katz SG. BOK controls apoptosis by Ca 2+ transfer through ER-mitochondrial contact sites. Cell Rep 2021; 34:108827. [PMID: 33691099 PMCID: PMC7995216 DOI: 10.1016/j.celrep.2021.108827] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 11/20/2020] [Accepted: 02/16/2021] [Indexed: 12/11/2022] Open
Abstract
Calcium transfer from the endoplasmic reticulum (ER) to mitochondria is a critical contributor to apoptosis. B cell lymphoma 2 (BCL-2) ovarian killer (BOK) localizes to the ER and binds the inositol 1,4,5-trisphosophate receptor (IP3R). Here, we show that BOK is necessary for baseline mitochondrial calcium levels and stimulus-induced calcium transfer from the ER to the mitochondria. Murine embryonic fibroblasts deficient for BOK have decreased proximity of the ER to the mitochondria and altered protein composition of mitochondria-associated membranes (MAMs), which form essential calcium microdomains. Rescue of the ER-mitochondrial juxtaposition with drug-inducible interorganelle linkers reveals a kinetic disruption, which when overcome in Bok−/− cells is still insufficient to rescue thapsigargin-induced calcium transfer and apoptosis. Likewise, a BOK mutant unable to interact with IP3R restores ER-mitochondrial proximity, but not ER-mitochondrial calcium transfer, MAM protein composition, or apoptosis. This work identifies the dynamic coordination of ER-mitochondrial contact by BOK as an important control point for apoptosis. Carpio et al. demonstrate that the proapoptotic BCL-2 family member BOK is present in mitochondrial associated membranes (MAMs). The interaction of BOK with the IP3Rs is critical for its regulation of Ca2+ transfer to the mitochondria, ER-mitochondrial contact sites, and apoptosis.
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Affiliation(s)
- Marcos A Carpio
- Department of Pathology, Yale School of Medicine, New Haven, CT 06525, USA
| | - Robert E Means
- Department of Pathology, Yale School of Medicine, New Haven, CT 06525, USA
| | - Allison L Brill
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06525, USA
| | - Alva Sainz
- Department of Pathology, Yale School of Medicine, New Haven, CT 06525, USA
| | - Barbara E Ehrlich
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06525, USA; Department of Pharmacology, Yale School of Medicine, New Haven, CT 06525, USA
| | - Samuel G Katz
- Department of Pathology, Yale School of Medicine, New Haven, CT 06525, USA.
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30
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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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Progression of heart failure is attenuated by antioxidant therapy with N-acetylcysteine in myocardial infarcted female rats. Mol Biol Rep 2020; 47:8645-8656. [PMID: 33048324 DOI: 10.1007/s11033-020-05907-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/07/2020] [Indexed: 01/09/2023]
Abstract
This study investigated the therapeutic potential of N-acetylcysteine (NAC) in the treatment of heart failure in female rats. Myocardial infarcted (MI) rats were given NAC (250 mg/kg/day p.o.) during 28 days after surgery (MI + NAC) or vehicle (MI + Placebo), and sham-operated rats received the same treatments (Sham + NAC and Sham + Placebo). Electrocardiographic and echocardiographic analyses were performed in the last week of treatment. Cardiac mRNA levels of types I and II superoxide dismutase (SOD), catalase, types I and III glutathione peroxidase (GPX), nerve growth factor (NGF), β1-adrenergic receptor (β1ADR), and type 2 muscarinic receptor (M2R) were assessed. Cardiac levels NADPH oxidase (NOX) activity, total content of reduced thiols, and SOD, GPX, and catalase activity were assessed. Compared to MI + Placebo group, MI + NAC group exhibited decreased NOX activity, increased content of reduced thiols, increased GPX activity, and normalized GPX III mRNA levels (p < 0.05). Heart and lung weights, left ventricular (LV) end-diastolic volume and left atrium/aorta ratio were decreased, while LV posterior wall thickness and ejection fraction were increased in MI + NAC group versus MI + Placebo rats (p < 0.05). Power density of low frequency band was decreased, while power density of high frequency and the root mean square of the successive differences were increased in MI + NAC rats versus MI + Placebo (p < 0.05). These findings indicate that NAC promotes therapeutic effects in the progression of MI-induced heart failure in female rats.
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32
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Loncke J, Kerkhofs M, Kaasik A, Bezprozvanny I, Bultynck G. Recent advances in understanding IP3R function with focus on ER-mitochondrial Ca2+ transfers. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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33
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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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34
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Dong Y, Lee Y, Cui K, He M, Wang B, Bhattacharjee S, Zhu B, Yago T, Zhang K, Deng L, Ouyang K, Wen A, Cowan DB, Song K, Yu L, Brophy ML, Liu X, Wylie-Sears J, Wu H, Wong S, Cui G, Kawashima Y, Matsumoto H, Kodera Y, Wojcikiewicz RJH, Srivastava S, Bischoff J, Wang DZ, Ley K, Chen H. Epsin-mediated degradation of IP3R1 fuels atherosclerosis. Nat Commun 2020; 11:3984. [PMID: 32770009 PMCID: PMC7414107 DOI: 10.1038/s41467-020-17848-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 07/15/2020] [Indexed: 12/18/2022] Open
Abstract
The epsin family of endocytic adapter proteins are widely expressed, and interact with both proteins and lipids to regulate a variety of cell functions. However, the role of epsins in atherosclerosis is poorly understood. Here, we show that deletion of endothelial epsin proteins reduces inflammation and attenuates atherosclerosis using both cell culture and mouse models of this disease. In atherogenic cholesterol-treated murine aortic endothelial cells, epsins interact with the ubiquitinated endoplasmic reticulum protein inositol 1,4,5-trisphosphate receptor type 1 (IP3R1), which triggers proteasomal degradation of this calcium release channel. Epsins potentiate its degradation via this interaction. Genetic reduction of endothelial IP3R1 accelerates atherosclerosis, whereas deletion of endothelial epsins stabilizes IP3R1 and mitigates inflammation. Reduction of IP3R1 in epsin-deficient mice restores atherosclerotic progression. Taken together, epsin-mediated degradation of IP3R1 represents a previously undiscovered biological role for epsin proteins and may provide new therapeutic targets for the treatment of atherosclerosis and other diseases. Endothelial cell (EC) dysfunction and inflammation contribute to plaque destabilization in atherosclerosis, increasing the risk of thrombotic events. Here, the authors show that epsin promotes EC inflammation via a mechanism involving IP3R1 degradation, and that deletion of epsin in the endothelium prevents EC dysfunctoin and atherosclerosis in mice.
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Affiliation(s)
- Yunzhou Dong
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Yang Lee
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Kui Cui
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Ming He
- Department of Medicine, University of California, San Diego, San Diego, CA, 92093, USA
| | - Beibei Wang
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Sudarshan Bhattacharjee
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Bo Zhu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Tadayuki Yago
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Kun Zhang
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Lin Deng
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Kunfu Ouyang
- Department of Medicine, University of California, San Diego, San Diego, CA, 92093, USA
| | - Aiyun Wen
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Douglas B Cowan
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.,Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Kai Song
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Lili Yu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Megan L Brophy
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Xiaolei Liu
- Center for Vascular and Developmental Biology, Feinberg Cardiovascular Research Institute, Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Jill Wylie-Sears
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Hao Wu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Scott Wong
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Guanglin Cui
- Department of Nutrition and Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Yusuke Kawashima
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.,Center for Disease Proteomics, Kitasato University School of Science, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Hiroyuki Matsumoto
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Yoshio Kodera
- Center for Disease Proteomics, Kitasato University School of Science, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | | | - Sanjay Srivastava
- Department of Medicine, Division of Cardiovascular Medicine, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Joyce Bischoff
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Da-Zhi Wang
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Klaus Ley
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA
| | - Hong Chen
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
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35
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Lamb HM. Double agents of cell death: novel emerging functions of apoptotic regulators. FEBS J 2020; 287:2647-2663. [PMID: 32239637 PMCID: PMC8796856 DOI: 10.1111/febs.15308] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 01/28/2020] [Accepted: 03/24/2020] [Indexed: 12/13/2022]
Abstract
Apoptosis is a highly regulated form of cell death that is required for many homeostatic and pathological processes. Recently, alternative cell death pathways have emerged whose regulation is dependent on proteins with canonical functions in apoptosis. Dysregulation of apoptotic signaling frequently underlies the pathogenesis of many cancers, reinforcing the need to develop therapies that initiate alternative cell death processes. This review outlines the convergence points between apoptosis and other death pathways with the purpose of identifying novel strategies for the treatment of apoptosis-refractory cancers. Apoptosis proteins can play key roles in the initiation, regulation, and execution of nonapoptotic death processes that include necroptosis, autophagy, pyroptosis, mPTP-mediated necrosis, and ferroptosis. Notably, recent evidence illustrates that dying cells can exhibit biochemical and molecular characteristics of more than one different type of regulated cell death. Thus, this review highlights the amazing complexity and interconnectivity of cell death processes and also raises the idea that a top-to-bottom approach to describing cell death mechanisms may be inadequate for fully understanding the means by which cells die.
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Affiliation(s)
- Heather M. Lamb
- W. Harry Feinstone Department of Molecular Microbiology and
Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore,
MD 21205 USA
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36
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Ivanova H, Vervliet T, Monaco G, Terry LE, Rosa N, Baker MR, Parys JB, Serysheva II, Yule DI, Bultynck G. Bcl-2-Protein Family as Modulators of IP 3 Receptors and Other Organellar Ca 2+ Channels. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035089. [PMID: 31501195 DOI: 10.1101/cshperspect.a035089] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The pro- and antiapoptotic proteins belonging to the B-cell lymphoma-2 (Bcl-2) family exert a critical control over cell-death processes by enabling or counteracting mitochondrial outer membrane permeabilization. Beyond this mitochondrial function, several Bcl-2 family members have emerged as critical modulators of intracellular Ca2+ homeostasis and dynamics, showing proapoptotic and antiapoptotic functions. Bcl-2 family proteins specifically target several intracellular Ca2+-transport systems, including organellar Ca2+ channels: inositol 1,4,5-trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs), Ca2+-release channels mediating Ca2+ flux from the endoplasmic reticulum, as well as voltage-dependent anion channels (VDACs), which mediate Ca2+ flux across the mitochondrial outer membrane into the mitochondria. Although the formation of protein complexes between Bcl-2 proteins and these channels has been extensively studied, a major advance during recent years has been elucidating the complex interaction of Bcl-2 proteins with IP3Rs. Distinct interaction sites for different Bcl-2 family members were identified in the primary structure of IP3Rs. The unique molecular profiles of these Bcl-2 proteins may account for their distinct functional outcomes when bound to IP3Rs. Furthermore, Bcl-2 inhibitors used in cancer therapy may affect IP3R function as part of their proapoptotic effect and/or as an adverse effect in healthy cells.
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Affiliation(s)
- Hristina Ivanova
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Tim Vervliet
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Giovanni Monaco
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Lara E Terry
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642
| | - Nicolas Rosa
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Mariah R Baker
- Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, Structural Biology Imaging Center, Houston, Texas 77030
| | - Jan B Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
| | - Irina I Serysheva
- Department of Biochemistry and Molecular Biology, McGovern Medical School at The University of Texas Health Science Center at Houston, Structural Biology Imaging Center, Houston, Texas 77030
| | - David I Yule
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, B-3000 Leuven, Belgium
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37
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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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New Insights in the IP 3 Receptor and Its Regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:243-270. [PMID: 31646513 DOI: 10.1007/978-3-030-12457-1_10] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) is a Ca2+-release channel mainly located in the endoplasmic reticulum (ER). Three IP3R isoforms are responsible for the generation of intracellular Ca2+ signals that may spread across the entire cell or occur locally in so-called microdomains. Because of their ubiquitous expression, these channels are involved in the regulation of a plethora of cellular processes, including cell survival and cell death. To exert their proper function a fine regulation of their activity is of paramount importance. In this review, we will highlight the recent advances in the structural analysis of the IP3R and try to link these data with the newest information concerning IP3R activation and regulation. A special focus of this review will be directed towards the regulation of the IP3R by protein-protein interaction. Especially the protein family formed by calmodulin and related Ca2+-binding proteins and the pro- and anti-apoptotic/autophagic Bcl-2-family members will be highlighted. Finally, recently identified and novel IP3R regulatory proteins will be discussed. A number of these interactions are involved in cancer development, illustrating the potential importance of modulating IP3R-mediated Ca2+ signaling in cancer treatment.
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39
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Zheng JH, Grace CR, Guibao CD, McNamara DE, Llambi F, Wang YM, Chen T, Moldoveanu T. Intrinsic Instability of BOK Enables Membrane Permeabilization in Apoptosis. Cell Rep 2019; 23:2083-2094.e6. [PMID: 29768206 PMCID: PMC6500462 DOI: 10.1016/j.celrep.2018.04.060] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 03/21/2018] [Accepted: 04/14/2018] [Indexed: 11/26/2022] Open
Abstract
The effector B cell lymphoma-2 (BCL-2) protein BCL-2 ovarian killer (BOK) induces mitochondrial outer membrane permeabilization (MOMP) to initiate apoptosis upon inhibition of the proteasome. How BOK mediates MOMP is mechanistically unknown. The NMR structure of the BCL-2 core of human BOK reveals a conserved architecture with an atypical hydrophobic groove that undergoes conformational exchange. Remarkably, the BCL-2 core of BOK spontaneously associates with purified mitochondria to release cytochrome c in MOMP assays. Alanine substitution of a unique glycine in helix α1 stabilizes BOK, as shown by thermal shift and urea denaturation analyses, and significantly inhibits MOMP, liposome permeabilization, and cell death. Activated BID does not activate WT BOK or the stabilized alanine mutant to promote cell death. We propose that BOK-mediated membrane permeabilization is governed in part by its unique metastability of the hydrophobic groove and helix α1 and not through activation by BH3 ligands.
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Affiliation(s)
- Janet H Zheng
- 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
| | - 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
| | - 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
| | | | - Yue-Ming Wang
- 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
| | - 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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40
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Abstract
In the body, extracellular stimuli produce inositol 1,4,5-trisphosphate (IP3), an intracellular chemical signal that binds to the IP3 receptor (IP3R) to release calcium ions (Ca2+) from the endoplasmic reticulum. In the past 40 years, the wide-ranging functions mediated by IP3R and its genetic defects causing a variety of disorders have been unveiled. Recent cryo-electron microscopy and X-ray crystallography have resolved IP3R structures and begun to integrate with concurrent functional studies, which can explicate IP3-dependent opening of Ca2+-conducting gates placed ∼90 Å away from IP3-binding sites and its regulation by Ca2+. This review highlights recent research progress on the IP3R structure and function. We also propose how protein plasticity within IP3R, which involves allosteric gating and assembly transformations accompanied by rapid and chronic structural changes, would enable it to regulate diverse functions at cellular microdomains in pathophysiological states.
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Affiliation(s)
- Kozo Hamada
- Laboratory of Cell Calcium Signaling, Shanghai Institute for Advanced Immunochemical Studies (SIAIS), ShanghaiTech University, Shanghai, 201210, China; ,
| | - Katsuhiko Mikoshiba
- Laboratory of Cell Calcium Signaling, Shanghai Institute for Advanced Immunochemical Studies (SIAIS), ShanghaiTech University, Shanghai, 201210, China; ,
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41
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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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42
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Prole DL, Taylor CW. Structure and Function of IP 3 Receptors. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a035063. [PMID: 30745293 DOI: 10.1101/cshperspect.a035063] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs), by releasing Ca2+ from the endoplasmic reticulum (ER) of animal cells, allow Ca2+ to be redistributed from the ER to the cytosol or other organelles, and they initiate store-operated Ca2+ entry (SOCE). For all three IP3R subtypes, binding of IP3 primes them to bind Ca2+, which then triggers channel opening. We are now close to understanding the structural basis of IP3R activation. Ca2+-induced Ca2+ release regulated by IP3 allows IP3Rs to regeneratively propagate Ca2+ signals. The smallest of these regenerative events is a Ca2+ puff, which arises from the nearly simultaneous opening of a small cluster of IP3Rs. Ca2+ puffs are the basic building blocks for all IP3-evoked Ca2+ signals, but only some IP3 clusters, namely those parked alongside the ER-plasma membrane junctions where SOCE occurs, are licensed to respond. The location of these licensed IP3Rs may allow them to selectively regulate SOCE.
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Affiliation(s)
- David L Prole
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom
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43
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Abstract
BCL-2 family members have additional roles beyond direct regulation of mitochondrial outer membrane permeabilization (MOMP) in apoptosis. One such important function is the release of calcium from the endoplasmic reticulum (ER), which critically contributes to the process of apoptosis. Here, we describe a protocol to measure calcium levels in the ER, mitochondria, and cytosol, with specific consideration of BCL-2 family biology.
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Affiliation(s)
- Marcos A Carpio
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.,CIQUIBIC-Department of Biological Chemistry, National University of Cordoba, Cordoba, Argentina
| | - Samuel G Katz
- Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.
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44
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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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45
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Distelhorst CW. Targeting Bcl-2-IP 3 receptor interaction to treat cancer: A novel approach inspired by nearly a century treating cancer with adrenal corticosteroid hormones. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1795-1804. [PMID: 30053503 DOI: 10.1016/j.bbamcr.2018.07.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 12/12/2022]
Abstract
Bcl-2 inhibits cell death by at least two different mechanisms. On the one hand, its BH3 domain binds to pro-apoptotic proteins such as Bim and prevents apoptosis induction. On the other hand, the BH4 domain of Bcl-2 binds to the inositol 1,4,5-trisphosphate receptor (IP3R), preventing Ca2+ signals that mediate cell death. In normal T-cells, Bcl-2 levels increase during the immune response, protecting against cell death, and then decline as apoptosis ensues and the immune response dissipates. But in many cancers Bcl-2 is aberrantly expressed and exploited to prevent cell death by inhibiting IP3R-mediated Ca2+ elevation. This review summarizes what is known about the mechanism of Bcl-2's control over IP3R-mediated Ca2+ release and cell death induction. Early insights into the role of Ca2+ elevation in corticosteroid-mediated cell death serves as a model for how targeting IP3R-mediated Ca2+ elevation can be a highly effective therapeutic approach for different types of cancer. Moreover, the successful development of ABT-199 (Venetoclax), a small molecule targeting the BH3 domain of Bcl-2 but without effects on Ca2+, serves as proof of principle that targeting Bcl-2 can be an effective therapeutic approach. BIRD-2, a synthetic peptide that inhibits Bcl-2-IP3R interaction, induces cell death induction in ABT-199 (Venetoclax)-resistant cancer models, attesting to the value of developing therapeutic agents that selectively target Bcl-2-IP3R interaction, inducing Ca2+-mediated cell death.
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Affiliation(s)
- Clark W Distelhorst
- Case Western University School of Medicine, Case Comprehensive Cancer Center, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, United States of America.
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46
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Wang L, Yule DI. Differential regulation of ion channels function by proteolysis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1698-1706. [PMID: 30009861 DOI: 10.1016/j.bbamcr.2018.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/06/2018] [Accepted: 07/10/2018] [Indexed: 12/23/2022]
Abstract
Ion channels are pore-forming protein complexes in membranes that play essential roles in a diverse array of biological activities. Ion channel activity is strictly regulated at multiple levels and by numerous cellular events to selectively activate downstream effectors involved in specific biological activities. For example, ions, binding proteins, nucleotides, phosphorylation, the redox state, channel subunit composition have all been shown to regulate channel activity and subsequently allow channels to participate in distinct cellular events. While these forms of modulation are well documented and have been extensively reviewed, in this article, we will first review and summarize channel proteolysis as a novel and quite widespread mechanism for altering channel activity. We will then highlight the recent findings demonstrating that proteolysis profoundly alters Inositol 1,4,5 trisphosphate receptor activity, and then discuss its potential functional ramifications in various developmental and pathological conditions.
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Affiliation(s)
- Liwei Wang
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, United States of America
| | - David I Yule
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, United States of America.
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47
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Bcl-2 inhibitors as anti-cancer therapeutics: The impact of and on calcium signaling. Cell Calcium 2018; 70:102-116. [DOI: 10.1016/j.ceca.2017.05.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 01/08/2023]
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48
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Popgeorgiev N, Jabbour L, Gillet G. Subcellular Localization and Dynamics of the Bcl-2 Family of Proteins. Front Cell Dev Biol 2018; 6:13. [PMID: 29497611 PMCID: PMC5819560 DOI: 10.3389/fcell.2018.00013] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/30/2018] [Indexed: 12/12/2022] Open
Abstract
Bcl-2 family proteins are recognized as major regulators of the mitochondrial pathway of apoptosis. They control the mitochondrial outer membrane permeabilization (MOMP) by directly localizing to this organelle. Further investigations demonstrated that Bcl-2 related proteins are also found in other intracellular compartments such as the endoplasmic reticulum, the Golgi apparatus, the nucleus and the peroxisomes. At the level of these organelles, Bcl-2 family proteins not only regulate MOMP in a remote fashion but also participate in major cellular processes including calcium homeostasis, cell cycle control and cell migration. With the advances of live cell imaging techniques and the generation of fluorescent recombinant proteins, it became clear that the distribution of Bcl-2 proteins inside the cell is a dynamic process which is profoundly affected by changes in the cellular microenvironment. Here, we describe the current knowledge related to the subcellular distribution of the Bcl-2 family of proteins and further emphasize on the emerging concept that this highly dynamic process is critical for cell fate determination.
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Affiliation(s)
- Nikolay Popgeorgiev
- Université de Lyon, Centre de Recherche en Cancérologie de Lyon, U1052 Institut National de la Santé et de la Recherche Médicale, UMR Centre National de la Recherche Scientifique 5286, Université Lyon I, Centre Léon Bérard, Lyon, France
| | - Lea Jabbour
- Université de Lyon, Centre de Recherche en Cancérologie de Lyon, U1052 Institut National de la Santé et de la Recherche Médicale, UMR Centre National de la Recherche Scientifique 5286, Université Lyon I, Centre Léon Bérard, Lyon, France
| | - Germain Gillet
- Université de Lyon, Centre de Recherche en Cancérologie de Lyon, U1052 Institut National de la Santé et de la Recherche Médicale, UMR Centre National de la Recherche Scientifique 5286, Université Lyon I, Centre Léon Bérard, Lyon, France.,Hospices Civils de Lyon, Laboratoire d'anatomie et Cytologie Pathologiques, Centre Hospitalier Lyon Sud, Pierre Bénite, France
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49
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The BAX/BAK-like protein BOK is a prognostic marker in colorectal cancer. Cell Death Dis 2018; 9:125. [PMID: 29374142 PMCID: PMC5833733 DOI: 10.1038/s41419-017-0140-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/27/2017] [Accepted: 11/07/2017] [Indexed: 12/18/2022]
Abstract
The intrinsic or mitochondrial apoptosis pathway is controlled by the interaction of antiapoptotic and pro-apoptotic members of the BCL-2 protein family. Activation of this death pathway plays a crucial role in cancer progression and chemotherapy responses. The BCL-2-related ovarian killer (BOK) possesses three BCL-2 homology domains and has been proposed to act in a similar pro-apoptotic pathway as the pro-apoptotic proteins BAX and BAK. In this study, we showed that stage II and III colorectal cancer patients possessed decreased levels of BOK protein in their tumours compared to matched normal tissue. BOK protein levels in tumours were also prognostic of clinical outcome but increased BOK protein levels surprisingly associated with earlier disease recurrence and reduced overall survival. We found no significant association of BOK protein tumour levels with ER stress markers GRP78 or GRP94 or with cleaved caspase-3. In contrast, BOK protein levels correlated with Calreticulin. These data indicate BOK as a prognostic marker in colorectal cancer and suggest that different activities of BOK may contribute to cancer progression and prognosis.
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50
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Yu R, Hou C, Lin H, Zhao J, Zong H, Lin Y. [Experimental study of urinary center change in pons after conus medullaris injury in rats]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2018; 32:75-79. [PMID: 29806370 DOI: 10.7507/1002-1892.201708126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 09/26/2022]
Abstract
Objective To observe the structural changes of urinary center and the expression of Bcl-2 after conus medullaris injury in rats brain so as to explore the possible influence factors of degeneration in brain. Methods Thirty-six adult Sprague-Dawley rats were randomly divided into experimental group ( n=30) and control group ( n=6). In the experimental group, the conus medullaris injury model was established by cutting off the spinal nerve below L 4, and no treatment was done in the control group. The modeling operations in the experimental group were successful, and 2 rats died at 3 months and 5 months after modeling operation respectively, which may be caused by renal failure or urinary tract infection. In the experimental group, 6, 6, 6, 5, and 5 rats were killed at 1 day, 1 week, and 1, 3, 6 months after operation respectively, and 1 rat was killed at each time point in the control group. The dorsolateral tissue of the pontine tegmentum was harvested to perform HE staining and Bcl-2 immunohistochemical SP staining. Results HE staining showed that there was no obvious difference between the experimental group and the control group at 1 day after operation, the neurons were densely packed, arranged neatly, and the nucleoli were clear; at 1 week, the space between the neurons in the experimental group were slightly widened; at 1 month, nucleus retraction in some neurons happened in the experimental group; at 3 and 6 months, the nuclei in the experimental group were more and more condensed, and even some cells disappeared. Bcl-2 immunohistochemical SP staining showed that the expression of Bcl-2 in the control group was weakly positive. The positive expression of Bcl-2 was found at 1 day after operation in the experimental group; the positive expression of Bcl-2 at 7 days after operation was significantly higher than that in the control group, and reached the peak; the positive expression of Bcl-2 decreased gradually at 1, 3, and 6 months after modeling operation, but it was still higher than that of the control group. Conclusion The urinary center appears structure degeneration and necrocytosis after conus medullaris injury in rats brain. The elevated expression of Bcl-2 may be associated with brain tissue repair and function remodeling.
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Affiliation(s)
- Ronghua Yu
- Second Military Medical University, Shanghai, 200433, P.R.China;Department of Orthopaedics, Changzheng Hospital, Shanghai, 200003, P.R.China
| | - Chunlin Hou
- Department of Orthopaedics, Changzheng Hospital, Shanghai, 200003,
| | - Haodong Lin
- Department of Orthopaedics, Changzheng Hospital, Shanghai, 200003, P.R.China
| | - Jianguo Zhao
- Department of Orthopaedics, Changzheng Hospital, Shanghai, 200003, P.R.China
| | - Haiyang Zong
- Department of Orthopaedics, Changzheng Hospital, Shanghai, 200003, P.R.China
| | - Yaofa Lin
- Department of Orthopaedics, Changzheng Hospital, Shanghai, 200003, P.R.China
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