1
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Mystek P, Singh V, Horváth M, Honzejková K, Riegerová P, Evci H, Hof M, Obšil T, Šachl R. The minimal membrane requirements for BAX-induced pore opening upon exposure to oxidative stress. Biophys J 2024:S0006-3495(24)00564-2. [PMID: 39188056 DOI: 10.1016/j.bpj.2024.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/18/2024] [Accepted: 08/22/2024] [Indexed: 08/28/2024] Open
Abstract
Perforation of the outer mitochondrial membrane triggered by BAX and facilitated by its main activator cBID is a fundamental process in cell apoptosis. Here, we employ a newly designed correlative approach based on a combination of a fluorescence cross correlation binding with a calcein permeabilization assay to understand the involvement of BAX in pore formation under oxidative stress conditions. To mimic the oxidative stress, we enriched liposomal membranes by phosphatidylcholines with truncated sn-2 acyl chains terminated by a carboxyl or aldehyde moiety. Our observations revealed that oxidative stress enhances proapoptotic conditions involving accelerated pore-opening kinetics. This enhancement is achieved through increased recruitment of BAX to the membrane and facilitation of BAX membrane insertion. Despite these effects, the fundamental mechanism of pore formation remained unchanged, suggesting an all-or-none mechanism. In line with this mechanism, we demonstrated that the minimal number of BAX molecules at the membrane necessary for pore formation remains constant regardless of BAX activation by cBID or the presence of oxidized lipids. Overall, our findings give a comprehensive picture of the molecular mechanisms underlying apoptotic pore formation and highlight the selective amplifying role of oxidized lipids in triggering formation of membrane pores.
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Affiliation(s)
- Paweł Mystek
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Vandana Singh
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czech Republic; Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - Matěj Horváth
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Karolína Honzejková
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Petra Riegerová
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Hüseyin Evci
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czech Republic; Department of Chemistry, Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice, Czech Republic
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Tomáš Obšil
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Radek Šachl
- J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Prague, Czech Republic.
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2
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Subas Satish HP, Iyer S, Shi MX, Wong AW, Fischer KC, Wardak AZ, Lio D, Brouwer JM, Uren RT, Czabotar PE, Miller MS, Kluck RM. A novel inhibitory BAK antibody enables assessment of non-activated BAK in cancer cells. Cell Death Differ 2024; 31:711-721. [PMID: 38582955 PMCID: PMC11164899 DOI: 10.1038/s41418-024-01289-3] [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: 11/13/2023] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/08/2024] Open
Abstract
BAX and BAK are pro-apoptotic members of the BCL2 family that are required to permeabilize the mitochondrial outer membrane. The proteins can adopt a non-activated monomeric conformation, or an activated conformation in which the exposed BH3 domain facilitates binding either to a prosurvival protein or to another activated BAK or BAX protein to promote pore formation. Certain cancer cells are proposed to have high levels of activated BAK sequestered by MCL1 or BCLXL, thus priming these cells to undergo apoptosis in response to BH3 mimetic compounds that target MCL1 or BCLXL. Here we report the first antibody, 14G6, that is specific for the non-activated BAK conformer. A crystal structure of 14G6 Fab bound to BAK revealed a binding site encompassing both the α1 helix and α5-α6 hinge regions of BAK, two sites involved in the unfolding of BAK during its activation. In mitochondrial experiments, 14G6 inhibited BAK unfolding triggered by three diverse BAK activators, supporting crucial roles for both α1 dissociation and separation of the core (α2-α5) and latch (α6-α9) regions in BAK activation. 14G6 bound the majority of BAK in several leukaemia cell lines, and binding decreased following treatment with BH3 mimetics, indicating only minor levels of constitutively activated BAK in those cells. In summary, 14G6 provides a new means of assessing BAK status in response to anti-cancer treatments.
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Affiliation(s)
- Hema Preethi Subas Satish
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Sweta Iyer
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Melissa X Shi
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Agnes W Wong
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Karla C Fischer
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Ahmad Z Wardak
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Daisy Lio
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Jason M Brouwer
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Rachel T Uren
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Peter E Czabotar
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Michelle S Miller
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia.
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia.
| | - Ruth M Kluck
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, VIC, 3052, Australia.
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, 3010, Australia.
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3
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Pays E. The Janus-faced functions of Apolipoproteins L in membrane dynamics. Cell Mol Life Sci 2024; 81:134. [PMID: 38478101 PMCID: PMC10937811 DOI: 10.1007/s00018-024-05180-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/06/2024] [Accepted: 02/18/2024] [Indexed: 03/17/2024]
Abstract
The functions of human Apolipoproteins L (APOLs) are poorly understood, but involve diverse activities like lysis of bloodstream trypanosomes and intracellular bacteria, modulation of viral infection and induction of apoptosis, autophagy, and chronic kidney disease. Based on recent work, I propose that the basic function of APOLs is the control of membrane dynamics, at least in the Golgi and mitochondrion. Together with neuronal calcium sensor-1 (NCS1) and calneuron-1 (CALN1), APOL3 controls the activity of phosphatidylinositol-4-kinase-IIIB (PI4KB), involved in both Golgi and mitochondrion membrane fission. Whereas secreted APOL1 induces African trypanosome lysis through membrane permeabilization of the parasite mitochondrion, intracellular APOL1 conditions non-muscular myosin-2A (NM2A)-mediated transfer of PI4KB and APOL3 from the Golgi to the mitochondrion under conditions interfering with PI4KB-APOL3 interaction, such as APOL1 C-terminal variant expression or virus-induced inflammatory signalling. APOL3 controls mitophagy through complementary interactions with the membrane fission factor PI4KB and the membrane fusion factor vesicle-associated membrane protein-8 (VAMP8). In mice, the basic APOL1 and APOL3 activities could be exerted by mAPOL9 and mAPOL8, respectively. Perspectives regarding the mechanism and treatment of APOL1-related kidney disease are discussed, as well as speculations on additional APOLs functions, such as APOL6 involvement in adipocyte membrane dynamics through interaction with myosin-10 (MYH10).
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Affiliation(s)
- Etienne Pays
- Laboratory of Molecular Parasitology, IBMM, Université Libre de Bruxelles, 6041, Gosselies, Belgium.
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4
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Lin Z, Long F, Kang R, Klionsky DJ, Yang M, Tang D. The lipid basis of cell death and autophagy. Autophagy 2024; 20:469-488. [PMID: 37768124 PMCID: PMC10936693 DOI: 10.1080/15548627.2023.2259732] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
ABBREVIATIONS ACSL: acyl-CoA synthetase long chain family; DISC: death-inducing signaling complex; DAMPs: danger/damage-associated molecular patterns; Dtgn: dispersed trans-Golgi network; FAR1: fatty acyl-CoA reductase 1; GPX4: glutathione peroxidase 4; LPCAT3: lysophosphatidylcholine acyltransferase 3; LPS: lipopolysaccharide; MUFAs: monounsaturated fatty acids; MOMP: mitochondrial outer membrane permeabilization; MLKL, mixed lineage kinase domain like pseudokinase; oxPAPC: oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine; OxPCs: oxidized phosphatidylcholines; PUFAs: polyunsaturated fatty acids; POR: cytochrome p450 oxidoreductase; PUFAs: polyunsaturated fatty acids; RCD: regulated cell death; RIPK1: receptor interacting serine/threonine kinase 1; SPHK1: sphingosine kinase 1; SOAT1: sterol O-acyltransferase 1; SCP2: sterol carrier protein 2; SFAs: saturated fatty acids; SLC47A1: solute carrier family 47 member 1; SCD: stearoyl-CoA desaturase; VLCFA: very long chain fatty acids.
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Affiliation(s)
- Zhi Lin
- Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Clinical Research Center of Pediatric Cancer, Changsha, Hunan, China
| | - Fei Long
- Department of Gastrointestinal Surgery, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
- Postdoctoral Research Station of Basic Medicine, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Rui Kang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
| | - Daniel J. Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Minghua Yang
- Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Clinical Research Center of Pediatric Cancer, Changsha, Hunan, China
| | - Daolin Tang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
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5
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Oliveira RC, Gama J, Casanova J. B-cell lymphoma 2 family members and sarcomas: a promising target in a heterogeneous disease. EXPLORATION OF TARGETED ANTI-TUMOR THERAPY 2023; 4:583-599. [PMID: 37720343 PMCID: PMC10501895 DOI: 10.37349/etat.2023.00154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 04/14/2023] [Indexed: 09/19/2023] Open
Abstract
Targeting the B-cell lymphoma 2 (Bcl-2) family proteins has been the backbone for hematological malignancies with overall survival improvements. The Bcl-2 family is a major player in apoptosis regulation and, has captured the researcher's interest in the treatment of solid tumors. Sarcomas are a heterogeneous group of diseases, comprising several entities, with high morbidity and mortality and with few specific therapies available. The treatment for sarcomas is based on platinum regimens, with variable results and poor outcomes, especially in advanced lesions. The high number of different sarcoma entities makes treatment standardization as well as the performance of clinical trials difficult. The use of Bcl-2 family members modifiers has revealed promising results in in vitro and in vivo models and may be a valid option, especially when used in combination with chemotherapy. In this article, a revision of these results and possibilities for the use of Bcl-2 family members inhibitors in sarcomas was performed.
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Affiliation(s)
- Rui Caetano Oliveira
- Centro de Anatomia Patológica Germano de Sousa, 3000 Coimbra, Portugal
- Coimbra Institute for Clinical and Biomedical Research (iCBR), 3000 Coimbra, Portugal
- Centre of Investigation on Genetics and Oncobiology (CIMAGO), 3000 Coimbra, Portugal
| | - João Gama
- Pathology Department, Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
| | - José Casanova
- Centre of Investigation on Genetics and Oncobiology (CIMAGO), 3000 Coimbra, Portugal
- Orthopedic Oncology Department, Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
- Faculdade de Medicina da Universidade de Coimbra, 3000 Coimbra, Portugal
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6
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Gołąbek-Grenda A, Kaczmarek M, Juzwa W, Olejnik A. Natural resveratrol analogs differentially target endometriotic cells into apoptosis pathways. Sci Rep 2023; 13:11468. [PMID: 37454164 PMCID: PMC10349804 DOI: 10.1038/s41598-023-38692-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023] Open
Abstract
The specific characteristics of endometriotic cells are their ability to evade the apoptotic machinery and abnormal response to apoptotic stimuli. Natural-originated compounds may constitute a beneficial strategy in apoptosis modulation in endometriosis. We investigated and compared the potency of natural resveratrol analogs, including piceatannol, polydatin, and pterostilbene, in targeting cell death pathways, including apoptosis-related morphologic and biochemical processes, alongside the modulation of the critical genes expression. Upon resveratrol and pterostilbene treatment, a significant reduction of endometriotic cell viability and an increased apoptotic proportion of cells were noted. The lower antiproliferative potential was found for piceatannol and polydatin. Endometrial stromal T HESC cells were significantly more resistant than endometriotic epithelial 12Z cells to the cytotoxic activity of all analyzed compounds. They differentially affected endometriotic cell viability, cell cycle, anti- and proapoptotic genes regulation, caspases expression and enzymatic activity, and DNA fragmentation. Pterostilbene-mediated endometriotic cell apoptosis modulation was confirmed to be most effective but without evident caspase 3 upregulation. Our study provides valuable insight into the apoptogenic activity of resveratrol and its natural analogs in endometriotic cells. Data obtained revealed the highest therapeutic potential of pterostilbene by effectively targeting cell death determinants in endometriosis, strengthening its optimization in further extensive research.
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Affiliation(s)
- Agata Gołąbek-Grenda
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, 48 Wojska Polskiego St., 60-627, Poznan, Poland
| | - Mariusz Kaczmarek
- Department of Cancer Immunology, Chair of Medical Biotechnology, Poznan University of Medical Sciences, 61-866, Poznan, Poland
- Department of Cancer Diagnostics and Immunology, Greater Poland Cancer Centre, 61-866, Poznan, Poland
| | - Wojciech Juzwa
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, 48 Wojska Polskiego St., 60-627, Poznan, Poland
| | - Anna Olejnik
- Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, 48 Wojska Polskiego St., 60-627, Poznan, Poland.
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7
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Clifton LA, Wacklin-Knecht HP, Ådén J, Mushtaq AU, Sparrman T, Gröbner G. Creation of distinctive Bax-lipid complexes at mitochondrial membrane surfaces drives pore formation to initiate apoptosis. SCIENCE ADVANCES 2023; 9:eadg7940. [PMID: 37267355 PMCID: PMC10413641 DOI: 10.1126/sciadv.adg7940] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/28/2023] [Indexed: 06/04/2023]
Abstract
Apotosis is an essential process tightly regulated by the Bcl-2 protein family where proapoptotic Bax triggers cell death by perforating the mitochondrial outer membrane. Although intensively studied, the molecular mechanism by which these proteins create apoptotic pores remains elusive. Here, we show that Bax creates pores by extracting lipids from outer mitochondrial membrane mimics by formation of Bax/lipid clusters that are deposited on the membrane surface. Time-resolved neutron reflectometry and Fourier transform infrared spectroscopy revealed two kinetically distinct phases in the pore formation process, both of which were critically dependent on cardiolipin levels. The initially fast adsorption of Bax on the mitochondrial membrane surface is followed by a slower formation of pores and Bax-lipid clusters on the membrane surface. Our findings provide a robust molecular understanding of mitochondrial membrane perforation by cell-killing Bax protein and illuminate the initial phases of programmed cellular death.
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Affiliation(s)
- Luke A. Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 OQX, UK
| | - Hanna P. Wacklin-Knecht
- European Spallation Source ERIC, ESS, P.O. Box 176, SE-22100 Lund, Sweden
- Department of Chemistry, Division of Physical Chemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
| | - Jörgen Ådén
- Department of Chemistry, University of Umeå, SE-90187 Umeå, Sweden
| | - Ameeq Ul Mushtaq
- Department of Chemistry, University of Umeå, SE-90187 Umeå, Sweden
| | - Tobias Sparrman
- Department of Chemistry, University of Umeå, SE-90187 Umeå, Sweden
| | - Gerhard Gröbner
- Department of Chemistry, University of Umeå, SE-90187 Umeå, Sweden
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8
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Dai H, Peterson KL, Flatten KS, Meng XW, Venkatachalam A, Correia C, Ramirez-Alvarado M, Pang YP, Kaufmann SH. A BAK subdomain that binds mitochondrial lipids selectively and releases cytochrome C. Cell Death Differ 2023; 30:794-808. [PMID: 36376382 PMCID: PMC9984382 DOI: 10.1038/s41418-022-01083-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 10/20/2022] [Accepted: 10/28/2022] [Indexed: 11/16/2022] Open
Abstract
How BAK and BAX induce mitochondrial outer membrane (MOM) permeabilization (MOMP) during apoptosis is incompletely understood. Here we have used molecular dynamics simulations, surface plasmon resonance, and assays for membrane permeabilization in vitro and in vivo to assess the structure and function of selected BAK subdomains and their derivatives. Results of these studies demonstrate that BAK helical regions α5 and α6 bind the MOM lipid cardiolipin. While individual peptides corresponding to these helical regions lack the full biological activity of BAK, tandem peptides corresponding to α4-α5, α5-α6, or α6-α7/8 can localize exogenous proteins to mitochondria, permeabilize liposomes composed of MOM lipids, and cause MOMP in the absence of the remainder of the BAK protein. Importantly, the ability of these tandem helices to induce MOMP under cell-free conditions is diminished by mutations that disrupt the U-shaped helix-turn-helix structure of the tandem peptides or decrease their lipid binding. Likewise, BAK-induced apoptosis in intact cells is diminished by CLS1 gene interruption, which decreases mitochondrial cardiolipin content, or by BAK mutations that disrupt the U-shaped tandem peptide structure or diminish lipid binding. Collectively, these results suggest that BAK structural rearrangements during apoptosis might mobilize helices involved in specific protein-lipid interactions that are critical for MOMP.
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Affiliation(s)
- Haiming Dai
- Division of Oncology Research, Mayo Clinic, Rochester, MN, 55905, USA.
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA.
- Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China.
- Hefei Cancer Hospital, Chinese Academy of Sciences, Hefei, 230031, China.
| | - Kevin L Peterson
- Division of Oncology Research, Mayo Clinic, Rochester, MN, 55905, USA
| | - Karen S Flatten
- Division of Oncology Research, Mayo Clinic, Rochester, MN, 55905, USA
| | - X Wei Meng
- Division of Oncology Research, Mayo Clinic, Rochester, MN, 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | | | - Cristina Correia
- Division of Oncology Research, Mayo Clinic, Rochester, MN, 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | | | - Yuan-Ping Pang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA
| | - Scott H Kaufmann
- Division of Oncology Research, Mayo Clinic, Rochester, MN, 55905, USA.
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, 55905, USA.
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9
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Pore-forming proteins as drivers of membrane permeabilization in cell death pathways. Nat Rev Mol Cell Biol 2022; 24:312-333. [PMID: 36543934 DOI: 10.1038/s41580-022-00564-w] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2022] [Indexed: 12/24/2022]
Abstract
Regulated cell death (RCD) relies on activation and recruitment of pore-forming proteins (PFPs) that function as executioners of specific cell death pathways: apoptosis regulator BAX (BAX), BCL-2 homologous antagonist/killer (BAK) and BCL-2-related ovarian killer protein (BOK) for apoptosis, gasdermins (GSDMs) for pyroptosis and mixed lineage kinase domain-like protein (MLKL) for necroptosis. Inactive precursors of PFPs are converted into pore-forming entities through activation, membrane recruitment, membrane insertion and oligomerization. These mechanisms involve protein-protein and protein-lipid interactions, proteolytic processing and phosphorylation. In this Review, we discuss the structural rearrangements incurred by RCD-related PFPs and describe the mechanisms that manifest conversion from autoinhibited to membrane-embedded molecular states. We further discuss the formation and maturation of membrane pores formed by BAX/BAK/BOK, GSDMs and MLKL, leading to diverse pore architectures. Lastly, we highlight commonalities and differences of PFP mechanisms involving BAX/BAK/BOK, GSDMs and MLKL and conclude with a discussion on how, in a population of challenged cells, the coexistence of cell death modalities may have profound physiological and pathophysiological implications.
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10
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Mushtaq AU, Ådén J, Ali K, Gröbner G. Domain-specific insight into the recognition of BH3-death motifs by the pro-survival Bcl-2 protein. Biophys J 2022; 121:4517-4525. [PMID: 36325615 PMCID: PMC9748362 DOI: 10.1016/j.bpj.2022.10.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 10/09/2022] [Accepted: 10/27/2022] [Indexed: 11/07/2022] Open
Abstract
Programmed mammalian cell death (apoptosis) is an essential mechanism in life that tightly regulates embryogenesis and removal of dysfunctional cells. In its intrinsic (mitochondrial) pathway, opposing members of the Bcl-2 (B cell lymphoma 2) protein family meet at the mitochondrial outer membrane (MOM) to control its integrity. Any imbalance can cause disorders, with upregulation of the cell-guarding antiapoptotic Bcl-2 protein itself being common in many, often incurable, cancers. Normally, the Bcl-2 protein itself is embedded in the MOM where it sequesters cell-killing apoptotic proteins such as Bax (Bcl-2-associated X protein) that would otherwise perforate the MOM and subsequently cause cell death. However, the molecular basis of Bcl-2's ability to recognize those apoptotic proteins via their common BH3 death motifs remains elusive due to the lack of structural insight. By employing nuclear magnetic resonance on fully functional human Bcl-2 protein in membrane-mimicking micelles, we identified glycine residues across all functional domains of the Bcl-2 protein and could monitor their residue-specific individual response upon the presence of a Bax-derived 36aa long BH3 domain. The observed chemical shift perturbations allowed us to determine the response and individual affinity of each glycine residue and provide an overall picture of the individual roles by which Bcl-2's functional domains engage in recognizing and inhibiting apoptotic proteins via their prominent BH3 motifs. This way, we provide a unique residue- and domain-specific insight into the molecular functioning of Bcl-2 at the membrane level, an insight also opening up for interfering with this cell-protecting mechanism in cancer therapy.
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Affiliation(s)
| | - Jörgen Ådén
- Department of Chemistry, University of Umeå, Umeå, Sweden
| | - Katan Ali
- Department of Chemistry, University of Umeå, Umeå, Sweden
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11
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Wolf P, Schoeniger A, Edlich F. Pro-apoptotic complexes of BAX and BAK on the outer mitochondrial membrane. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119317. [PMID: 35752202 DOI: 10.1016/j.bbamcr.2022.119317] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/02/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
In multicellular organisms the regulated cell death apoptosis is critically important for both ontogeny and homeostasis. Mitochondria are indispensable for stress-induced apoptosis. The BCL-2 protein family controls mitochondrial apoptosis and initiates cell death through the pro-apoptotic activities of BAX and BAK at the outer mitochondrial membrane (OMM). Cellular survival is ensured by the retrotranslocation of mitochondrial BAX and BAK into the cytosol by anti-apoptotic BCL-2 proteins. BAX/BAK-dependent OMM permeabilization releases the mitochondrial cytochrome c (cyt c), which initiates activation of caspase-9. The caspase cascade leads to cell shrinkage, plasma membrane blebbing, chromatin condensation, and apoptotic body formation. Although it is clear that ultimately complexes of active BAX and BAK commit the cell to apoptosis, the nature of these complexes is still enigmatic. Excessive research has described a range of complexes, varying from a few molecules to several 10,000, in different systems. BAX/BAK complexes potentially form ring-like structures that could expose the inner mitochondrial membrane. It has been suggested that these pores allow the efflux of small proteins and even mitochondrial DNA. Here we summarize the current state of knowledge for mitochondrial BAX/BAK complexes and the interactions between these proteins and the membrane.
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Affiliation(s)
- Philipp Wolf
- Institute of Biochemistry, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Axel Schoeniger
- Institute of Biochemistry, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Frank Edlich
- Institute of Biochemistry, Faculty of Veterinary Medicine, University of Leipzig, 04103 Leipzig, Germany.
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12
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Marwarha G, Røsand Ø, Slagsvold KH, Høydal MA. GSK3β Inhibition Is the Molecular Pivot That Underlies the Mir-210-Induced Attenuation of Intrinsic Apoptosis Cascade during Hypoxia. Int J Mol Sci 2022; 23:ijms23169375. [PMID: 36012628 PMCID: PMC9409400 DOI: 10.3390/ijms23169375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/09/2022] [Accepted: 08/17/2022] [Indexed: 11/16/2022] Open
Abstract
Apoptotic cell death is a deleterious consequence of hypoxia-induced cellular stress. The master hypoxamiR, microRNA-210 (miR-210), is considered the primary driver of the cellular response to hypoxia stress. We have recently demonstrated that miR-210 attenuates hypoxia-induced apoptotic cell death. In this paper, we unveil that the miR-210-induced inhibition of the serine/threonine kinase Glycogen Synthase Kinase 3 beta (GSK3β) in AC-16 cardiomyocytes subjected to hypoxia stress underlies the salutary protective response of miR-210 in mitigating the hypoxia-induced apoptotic cell death. Using transient overexpression vectors to augment miR-210 expression concomitant with the ectopic expression of the constitutive active GSK3β S9A mutant (ca-GSK3β S9A), we exhaustively performed biochemical and molecular assays to determine the status of the hypoxia-induced intrinsic apoptosis cascade. Caspase-3 activity analysis coupled with DNA fragmentation assays cogently demonstrate that the inhibition of GSK3β kinase activity underlies the miR-210-induced attenuation in the hypoxia-driven apoptotic cell death. Further elucidation and delineation of the upstream cellular events unveiled an indispensable role of the inhibition of GSK3β kinase activity in mediating the miR-210-induced mitigation of the hypoxia-driven BAX and BAK insertion into the outer mitochondria membrane (OMM) and the ensuing Cytochrome C release into the cytosol. Our study is the first to unveil that the inhibition of GSK3β kinase activity is indispensable in mediating the miR-210-orchestrated protective cellular response to hypoxia-induced apoptotic cell death.
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Affiliation(s)
- Gurdeep Marwarha
- Group of Molecular and Cellular Cardiology, Department of Circulation and Medical Imaging, Faculty of Medicine and Health, Norwegian University of Science and Technology (NTNU), 7034 Trondheim, Norway
| | - Øystein Røsand
- Group of Molecular and Cellular Cardiology, Department of Circulation and Medical Imaging, Faculty of Medicine and Health, Norwegian University of Science and Technology (NTNU), 7034 Trondheim, Norway
| | - Katrine Hordnes Slagsvold
- Group of Molecular and Cellular Cardiology, Department of Circulation and Medical Imaging, Faculty of Medicine and Health, Norwegian University of Science and Technology (NTNU), 7034 Trondheim, Norway
- Department of Cardiothoracic Surgery, St. Olavs University Hospital, 7030 Trondheim, Norway
| | - Morten Andre Høydal
- Group of Molecular and Cellular Cardiology, Department of Circulation and Medical Imaging, Faculty of Medicine and Health, Norwegian University of Science and Technology (NTNU), 7034 Trondheim, Norway
- Correspondence: ; Tel.: +47-48134843
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13
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Kyrychenko A, Vasquez-Montes V, Ladokhin AS. Advantages of Quantitative Analysis of Depth-Dependent Fluorescence Quenching: Case Study of BAX. J Membr Biol 2022; 255:461-468. [PMID: 34994819 DOI: 10.1007/s00232-021-00211-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 12/15/2021] [Indexed: 11/26/2022]
Abstract
Dynamic disorder of the lipid bilayer presents a challenge for establishing structure-function relationships in membrane proteins, especially to those that insert by refolding from soluble states, e.g., bacterial toxins and Bcl-2 apoptotic regulators. Because many high-resolution structural techniques cannot be easily applied to such systems, methods like depth-dependent fluorescence quenching gained prominence. Over three decades ago, Prof. Erwin London and his co-workers revolutionized the studies of membrane protein insertion by introducing a quantitative approach to the analysis of membrane quenching data and inspired many researchers to continue this work. Here, we illustrate how the application of the quantitative analysis yields new insights into previously published results. We have used the method of distribution analysis (DA) to calculate the precise immersion depth of NBD fluorophores selectively attached to various single-cysteine mutants of the apoptotic factor BAX from quenching data obtained with a series of spin-labeled lipids. The original qualitative analysis interpreted the higher quenching determined for shallower probes in positions flanking the helix 9 of BAX as evidence of a transmembrane helix 9 topology. The quantitative DA, however, revealed that a transmembrane topology of helix 9 of BAX is unlikely, as it would require labeling sites that are only 15 residues apart in a helical conformation to be separated by a transverse distance of over 45 Å.
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Affiliation(s)
- Alexander Kyrychenko
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS, 66160-7421, USA.
- Institute of Chemistry and School of Chemistry, V. N. Karazin Kharkiv National University, 4 Svobody Square, Kharkiv, 61022, Ukraine.
| | - Victor Vasquez-Montes
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS, 66160-7421, USA
| | - Alexey S Ladokhin
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS, 66160-7421, USA
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14
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Apoptosis, Pyroptosis, and Necroptosis-Oh My! The Many Ways a Cell Can Die. J Mol Biol 2021; 434:167378. [PMID: 34838807 DOI: 10.1016/j.jmb.2021.167378] [Citation(s) in RCA: 150] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/12/2021] [Accepted: 11/21/2021] [Indexed: 12/12/2022]
Abstract
Cell death is an essential process in all living organisms and occurs through different mechanisms. The three main types of programmed cell death are apoptosis, pyroptosis, and necroptosis, and each of these pathways employs complex molecular and cellular mechanisms. Although there are mechanisms and outcomes specific to each pathway, they share common components and features. In this review, we discuss recent discoveries in these three best understood modes of cell death, highlighting their singularities, and examining the intriguing notion that common players shape different individual pathways in this highly interconnected and coordinated cell death system. Understanding the similarities and differences of these cell death processes is crucial to enable targeted strategies to manipulate these pathways for therapeutic benefit.
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15
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Speir M, Chan AH, Simpson DS, Khan T, Saunders TL, Poon IK, Atkin-Smith GK. The Australasian Cell Death Society (ACDS): celebrating 50 years of Australasian cell death research. Immunol Cell Biol 2021; 100:9-14. [PMID: 34761822 DOI: 10.1111/imcb.12510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 11/28/2022]
Affiliation(s)
- Mary Speir
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Molecular and Translational Science, Monash University, Clayton, VIC, Australia
| | - Amy H Chan
- Institute for Molecular Bioscience (IMB), IMB Centre for Inflammation and Disease Research, The University of Queensland, St Lucia, QLD, Australia
| | - Daniel S Simpson
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Tashbib Khan
- Beth Israel Deaconess Medical Centre, Harvard Medical School, Boston, MA, USA
| | - Tahnee L Saunders
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Ivan Kh Poon
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, Australia
| | - Georgia K Atkin-Smith
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, Australia
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16
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Sperl LE, Rührnößl F, Schiller A, Haslbeck M, Hagn F. High-resolution analysis of the conformational transition of pro-apoptotic Bak at the lipid membrane. EMBO J 2021; 40:e107159. [PMID: 34523144 PMCID: PMC8521305 DOI: 10.15252/embj.2020107159] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 08/09/2021] [Accepted: 08/20/2021] [Indexed: 12/21/2022] Open
Abstract
Permeabilization of the outer mitochondrial membrane by pore-forming Bcl2 proteins is a crucial step for the induction of apoptosis. Despite a large set of data suggesting global conformational changes within pro-apoptotic Bak during pore formation, high-resolution structural details in a membrane environment remain sparse. Here, we used NMR and HDX-MS (Hydrogen deuterium exchange mass spectrometry) in lipid nanodiscs to gain important high-resolution structural insights into the conformational changes of Bak at the membrane that are dependent on a direct activation by BH3-only proteins. Furthermore, we determined the first high-resolution structure of the Bak transmembrane helix. Upon activation, α-helix 1 in the soluble domain of Bak dissociates from the protein and adopts an unfolded and dynamic potentially membrane-bound state. In line with this finding, comparative protein folding experiments with Bak and anti-apoptotic BclxL suggest that α-helix 1 in Bak is a metastable structural element contributing to its pro-apoptotic features. Consequently, mutagenesis experiments aimed at stabilizing α-helix 1 yielded Bak variants with delayed pore-forming activity. These insights will contribute to a better mechanistic understanding of Bak-mediated membrane permeabilization.
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Affiliation(s)
- Laura E Sperl
- Bavarian NMR Center at the Department of ChemistryTechnical University of MunichGarchingGermany
- Institute of Structural BiologyHelmholtz Zentrum MünchenNeuherbergGermany
| | - Florian Rührnößl
- Center for Functional Protein Assemblies and Department of ChemistryTechnical University of MunichGarchingGermany
| | - Anita Schiller
- Bavarian NMR Center at the Department of ChemistryTechnical University of MunichGarchingGermany
- Institute of Structural BiologyHelmholtz Zentrum MünchenNeuherbergGermany
| | - Martin Haslbeck
- Center for Functional Protein Assemblies and Department of ChemistryTechnical University of MunichGarchingGermany
| | - Franz Hagn
- Bavarian NMR Center at the Department of ChemistryTechnical University of MunichGarchingGermany
- Institute of Structural BiologyHelmholtz Zentrum MünchenNeuherbergGermany
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17
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Rose M, Kurylowicz M, Mahmood M, Winkel S, Moran-Mirabal JM, Fradin C. Direct Measurement of the Affinity between tBid and Bax in a Mitochondria-Like Membrane. Int J Mol Sci 2021; 22:8240. [PMID: 34361006 PMCID: PMC8348223 DOI: 10.3390/ijms22158240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 01/05/2023] Open
Abstract
The execution step in apoptosis is the permeabilization of the outer mitochondrial membrane, controlled by Bcl-2 family proteins. The physical interactions between the different proteins in this family and their relative abundance literally determine the fate of the cells. These interactions, however, are difficult to quantify, as they occur in a lipid membrane and involve proteins with multiple conformations and stoichiometries which can exist both in soluble and membrane. Here we focus on the interaction between two core Bcl-2 family members, the executor pore-forming protein Bax and the truncated form of the activator protein Bid (tBid), which we imaged at the single particle level in a mitochondria-like planar supported lipid bilayer. We inferred the conformation of the proteins from their mobility, and detected their transient interactions using a novel single particle cross-correlation analysis. We show that both tBid and Bax have at least two different conformations at the membrane, and that their affinity for one another increases by one order of magnitude (with a 2D-KD decreasing from ≃1.6μm-2 to ≃0.1μm-2) when they pass from their loosely membrane-associated to their transmembrane form. We conclude by proposing an updated molecular model for the activation of Bax by tBid.
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Affiliation(s)
- Markus Rose
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Martin Kurylowicz
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Mohammad Mahmood
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Sheldon Winkel
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Jose M. Moran-Mirabal
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada;
| | - Cécile Fradin
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
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18
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Lv F, Qi F, Zhang Z, Wen M, Kale J, Piai A, Du L, Wang S, Zhou L, Yang Y, Wu B, Liu Z, Del Rosario J, Pogmore J, Chou JJ, Andrews DW, Lin J, OuYang B. An amphipathic Bax core dimer forms part of the apoptotic pore wall in the mitochondrial␣membrane. EMBO J 2021; 40:e106438. [PMID: 34101209 PMCID: PMC8280806 DOI: 10.15252/embj.2020106438] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 04/17/2021] [Accepted: 04/27/2021] [Indexed: 02/01/2023] Open
Abstract
Bax proteins form pores in the mitochondrial outer membrane to initiate apoptosis. This might involve their embedding in the cytosolic leaflet of the lipid bilayer, thus generating tension to induce a lipid pore with radially arranged lipids forming the wall. Alternatively, Bax proteins might comprise part of the pore wall. However, there is no unambiguous structural evidence for either hypothesis. Using NMR, we determined a high-resolution structure of the Bax core region, revealing a dimer with the nonpolar surface covering the lipid bilayer edge and the polar surface exposed to water. The dimer tilts from the bilayer normal, not only maximizing nonpolar interactions with lipid tails but also creating polar interactions between charged residues and lipid heads. Structure-guided mutations demonstrate the importance of both types of protein-lipid interactions in Bax pore assembly and core dimer configuration. Therefore, the Bax core dimer forms part of the proteolipid pore wall to permeabilize mitochondria.
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Affiliation(s)
- Fujiao Lv
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Fei Qi
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Zhi Zhang
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Maorong Wen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Justin Kale
- Biological Sciences, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
| | - Alessandro Piai
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Lingyu Du
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Shuqing Wang
- School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Liujuan Zhou
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yaqing Yang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Bin Wu
- National Facility for Protein Science in Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Zhijun Liu
- National Facility for Protein Science in Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Juan Del Rosario
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Justin Pogmore
- Biological Sciences, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
| | - James J Chou
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - David W Andrews
- Biological Sciences, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
| | - Jialing Lin
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Stephenson Cancer Center, Oklahoma City, OK, USA
| | - Bo OuYang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
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19
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Hung CL, Chang HH, Lee SW, Chiang YW. Stepwise activation of the pro-apoptotic protein Bid at mitochondrial membranes. Cell Death Differ 2021; 28:1910-1925. [PMID: 33462413 PMCID: PMC8184993 DOI: 10.1038/s41418-020-00716-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 12/01/2020] [Accepted: 12/16/2020] [Indexed: 01/30/2023] Open
Abstract
Caspase-8-cleaved Bid (cBid) associates with mitochondria and promotes the activation of BAX, leading to mitochondria outer membrane permeabilization (MOMP) and apoptosis. However, current structural models of cBid are largely based on studies using membrane vesicles and detergent micelles. Here we employ spin-label ESR and site-directed PEGylation methods to identify conformations of cBid at real mitochondrial membranes, revealing stepwise mechanisms in the activation process. Upon the binding of cBid to mitochondria, its structure is reorganized to expose the BH3 domain while leaving the structural integrity only slightly altered. The mitochondria-bound cBid is in association with Mtch2 and it remains in the primed state until interacting with BAX. The interaction subsequently triggers the fragmentation of cBid, causes large conformational changes, and promotes BAX-mediated MOMP. Our results reveal structural differences of cBid between mitochondria and other lipid-like environments and, moreover, highlight the role of the membrane binding in modifying cBid structure and assisting the inactive-to-active transition in function.
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Affiliation(s)
- Chien-Lun Hung
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Hsin-Ho Chang
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Su Wei Lee
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Yun-Wei Chiang
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan.
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20
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Birkinshaw RW, Iyer S, Lio D, Luo CS, Brouwer JM, Miller MS, Robin AY, Uren RT, Dewson G, Kluck RM, Colman PM, Czabotar PE. Structure of detergent-activated BAK dimers derived from the inert monomer. Mol Cell 2021; 81:2123-2134.e5. [PMID: 33794146 DOI: 10.1016/j.molcel.2021.03.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 01/11/2021] [Accepted: 03/09/2021] [Indexed: 01/27/2023]
Abstract
A body of data supports the existence of core (α2-α5) dimers of BAK and BAX in the oligomeric, membrane-perturbing conformation of these essential apoptotic effector molecules. Molecular structures for these dimers have only been captured for truncated constructs encompassing the core domain alone. Here, we report a crystal structure of BAK α2-α8 dimers (i.e., minus its flexible N-terminal helix and membrane-anchoring C-terminal segment) that has been obtained through the activation of monomeric BAK with the detergent C12E8. Core dimers are evident, linked through the crystal by contacts via latch (α6-α8) domains. This crystal structure shows activated BAK dimers with the extended latch domain present. Our data provide direct evidence for the conformational change converting BAK from inert monomer to the functional dimer that destroys mitochondrial integrity. This dimer is the smallest functional unit for recombinant BAK or BAX described so far.
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Affiliation(s)
- Richard W Birkinshaw
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia.
| | - Sweta Iyer
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Daisy Lio
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Cindy S Luo
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Jason M Brouwer
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Michelle S Miller
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Adeline Y Robin
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Rachel T Uren
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Grant Dewson
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Ruth M Kluck
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Peter M Colman
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Peter E Czabotar
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia.
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21
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Mushtaq AU, Ådén J, Clifton LA, Wacklin-Knecht H, Campana M, Dingeldein APG, Persson C, Sparrman T, Gröbner G. Neutron reflectometry and NMR spectroscopy of full-length Bcl-2 protein reveal its membrane localization and conformation. Commun Biol 2021; 4:507. [PMID: 33907308 PMCID: PMC8079415 DOI: 10.1038/s42003-021-02032-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 03/25/2021] [Indexed: 12/20/2022] Open
Abstract
B-cell lymphoma 2 (Bcl-2) proteins are the main regulators of mitochondrial apoptosis. Anti-apoptotic Bcl-2 proteins possess a hydrophobic tail-anchor enabling them to translocate to their target membrane and to shift into an active conformation where they inhibit pro-apoptotic Bcl-2 proteins to ensure cell survival. To address the unknown molecular basis of their cell-protecting functionality, we used intact human Bcl-2 protein natively residing at the mitochondrial outer membrane and applied neutron reflectometry and NMR spectroscopy. Here we show that the active full-length protein is entirely buried into its target membrane except for the regulatory flexible loop domain (FLD), which stretches into the aqueous exterior. The membrane location of Bcl-2 and its conformational state seems to be important for its cell-protecting activity, often infamously upregulated in cancers. Most likely, this situation enables the Bcl-2 protein to sequester pro-apoptotic Bcl-2 proteins at the membrane level while sensing cytosolic regulative signals via its FLD region.
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Affiliation(s)
| | - Jörgen Ådén
- Department of Chemistry, University of Umeå, Umeå, Sweden
| | - Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science&Innovation Campus, Didcot, Oxfordshire, UK
| | - Hanna Wacklin-Knecht
- European Spallation Source ERIC, ESS, Lund, Sweden
- Department of Chemistry, Division of Physical Chemistry, Lund University, Lund, Sweden
| | - Mario Campana
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science&Innovation Campus, Didcot, Oxfordshire, UK
| | | | - Cecilia Persson
- The Swedish NMR Center, University of Gothenburg, Gothenburg, Sweden
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22
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Targeting BCL-2 in Cancer: Advances, Challenges, and Perspectives. Cancers (Basel) 2021; 13:cancers13061292. [PMID: 33799470 PMCID: PMC8001391 DOI: 10.3390/cancers13061292] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/08/2021] [Accepted: 03/10/2021] [Indexed: 12/19/2022] Open
Abstract
Simple Summary Apoptosis, a programmed form of cell death, represents the main mechanism by which cells die. Such phenomenon is highly regulated by the BCL-2 family of proteins, which includes both pro-apoptotic and pro-survival proteins. The decision whether cells live or die is tightly controlled by a balance between these two classes of proteins. Notably, the pro-survival Bcl-2 proteins are frequently overexpressed in cancer cells dysregulating this balance in favor of survival and also rendering cells more resistant to therapeutic interventions. In this review, we outlined the most important steps in the development of targeting the BCL-2 survival proteins, which laid the ground for the discovery and the development of the selective BCL-2 inhibitor venetoclax as a therapeutic drug in hematological malignancies. The limitations and future directions are also discussed. Abstract The major form of cell death in normal as well as malignant cells is apoptosis, which is a programmed process highly regulated by the BCL-2 family of proteins. This includes the antiapoptotic proteins (BCL-2, BCL-XL, MCL-1, BCLW, and BFL-1) and the proapoptotic proteins, which can be divided into two groups: the effectors (BAX, BAK, and BOK) and the BH3-only proteins (BIM, BAD, NOXA, PUMA, BID, BIK, HRK). Notably, the BCL-2 antiapoptotic proteins are often overexpressed in malignant cells. While this offers survival advantages to malignant cells and strengthens their drug resistance capacity, it also offers opportunities for novel targeted therapies that selectively kill such cells. This review provides a comprehensive overview of the extensive preclinical and clinical studies targeting BCL-2 proteins with various BCL-2 proteins inhibitors with emphasis on venetoclax as a single agent, as well as in combination with other therapeutic agents. This review also discusses recent advances, challenges focusing on drug resistance, and future perspectives for effective targeting the Bcl-2 family of proteins in cancer.
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23
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Price DA, Hill TD, Hutson KA, Rightnowar BW, Moran SD. Membrane-dependent amyloid aggregation of human BAX α9 (173-192). Protein Sci 2021; 30:1072-1080. [PMID: 33641228 DOI: 10.1002/pro.4053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 02/08/2021] [Accepted: 02/24/2021] [Indexed: 11/07/2022]
Abstract
Mitochondrial outer membrane permeabilization, which is a critical step in apoptosis, is initiated upon transmembrane insertion of the C-terminal α-helix (α9) of the proapoptotic Bcl-2 family protein BAX. The isolated α9 fragment (residues 173-192) is also competent to disrupt model membranes, and the structures of its membrane-associated oligomers are of interest in understanding the potential roles of this sequence in apoptosis. Here, we used ultrafast two-dimensional infrared (2D IR) spectroscopy, thioflavin T binding, and transmission electron microscopy to show that the synthetic BAX α9 peptide (α9p) forms amyloid aggregates in aqueous environments and on the surfaces of anionic small unilamellar vesicles. Its inherent amyloidogenicity was predicted by sequence analysis, and 2D IR spectra reveal that vesicles modulate the β-sheet structures of insoluble aggregates, motivating further examination of the formation or suppression of BAX amyloids in apoptosis.
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Affiliation(s)
- David A Price
- Department of Chemistry and Biochemistry, Southern Illinois University Carbondale, Carbondale, Illinois, USA
| | - Tayler D Hill
- Department of Chemistry and Biochemistry, Southern Illinois University Carbondale, Carbondale, Illinois, USA
| | - Kaitlyn A Hutson
- Department of Chemistry and Biochemistry, Southern Illinois University Carbondale, Carbondale, Illinois, USA
| | - Blaze W Rightnowar
- Department of Chemistry and Biochemistry, Southern Illinois University Carbondale, Carbondale, Illinois, USA
| | - Sean D Moran
- Department of Chemistry and Biochemistry, Southern Illinois University Carbondale, Carbondale, Illinois, USA
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Eliwa H, Brizard B, Le Guisquet AM, Hen R, Belzung C, Surget A. Adult neurogenesis augmentation attenuates anhedonia and HPA axis dysregulation in a mouse model of chronic stress and depression. Psychoneuroendocrinology 2021; 124:105097. [PMID: 33302237 PMCID: PMC8715720 DOI: 10.1016/j.psyneuen.2020.105097] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/06/2020] [Accepted: 11/26/2020] [Indexed: 11/26/2022]
Abstract
Major depressive disorder is a common debilitating mental health problem that represents one of the leading causes of disability. Up to date, the therapeutic targets and approaches are still limited. Adult hippocampal neurogenesis (AHN) has been proposed as a critical contributor to the pathophysiology and treatment of depression, altering the hippocampal control over stress response at network, neuroendocrine and behavioral levels. These findings together have suggested that manipulating AHN may be a promising therapeutic strategy for depression. To investigate this question, we assessed whether increasing adult neurogenesis would be sufficient to produce antidepressant-like effects at behavioral and neuroendocrine levels in a mouse model of depression; the unpredictable chronic mild stress (UCMS). For this purpose, we used a bi-transgenic mouse line (iBax) in which AHN increase was induced by deletion of the pro-apoptotic gene Bax from the neural progenitors following the tamoxifen-dependent action of CreERT2 recombinases. UCMS induced a syndrome that is reminiscent of depression-like states, including anhedonia (cookie test), physical changes (coat deterioration, reduced weight gain), anxiety-like behaviors (higher latency in the novelty-supressed feeding -NSF- test), passive stress-coping behaviors (immobility in the forced swim test -FST-) and a blunted hypothalamo-pituitary-adrenal (HPA) axis reactivity to acute stress in addition to AHN decrease. Tamoxifen injection reversed the AHN decrease as well as partly counteracted UCMS effects on the cookie test and HPA axis but not for the coat state, weight gain, NSF test and FST. Taken together, our results suggest that a strategy directing at increasing AHN may be able to alleviate some depression-related behavioral and neuroendocrine dimensions of UCMS, such as anhedonia and HPA axis reactivity deficits, but may be hardly sufficient to produce a complete recovery.
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Affiliation(s)
- Hoda Eliwa
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France; Department of Cell Biology, Medical Research Institute, Alexandria University, Egypt
| | - Bruno Brizard
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France
| | | | - René Hen
- Departments of Neuroscience, Psychiatry, & Pharmacology, Columbia University, New York, NY, USA; Division of Integrative Neuroscience, Department of Psychiatry, New York State Psychiatric Institute, New York, NY, USA; Kavli Institute for Brain Sciences, Columbia University, New York, NY, USA
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25
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Abstract
Chemical compounds induce cytotoxicity by various mechanisms, including interference in membrane integrity, metabolism, cellular component degradation or release, and cell division. Between the classic death pathways, namely, autophagy, apoptosis, and necrosis, apoptosis have been in the focus for the last several years as an important pathway for the toxicity of different types of xenobiotics. Because of that, having the tools to evaluate it is key for understanding and explaining the toxicodynamics of different classes of substances. Here, we describe a wide array of classic assays that can be easily implemented to evaluate apoptosis induction.
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Affiliation(s)
- Lilian Cristina Pereira
- Department of Clinical, Toxicological and Bromatological Analysis, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
- Department of Bioprocesses and Biotechnology, Faculty of Agronomic Sciences of Botucatu, São Paulo State University, Botucatu, SP, Brazil
- Center for Evaluation of Environmental Impact on Human Health (TOXICAM), Botucatu, São Paulo, Brazil
| | - Alecsandra Oliveira de Souza
- Federal Institute of Science and Technology Education of Rondônia-Campus Porto Velho Calama, Porto Velho, RO, Brazil
- FFCLRP-USP, Department of Chemistry, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Raul Ghiraldelli Miranda
- Department of Clinical, Toxicological and Bromatological Analysis, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Daniel Junqueira Dorta
- FFCLRP-USP, Department of Chemistry, Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
- Instituto Nacional de Tecnologias Alternativas de Detecção, Avaliação Toxicológica e Remoção de Micropututantes e Radioativos (INCT-DATREM), Unesp, Instituto de Química, Caixa Postal 355, CEP: 14800-900, Araraquara, SP, Brazil.
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26
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Flores‐Romero H, Ros U, Garcia‐Saez AJ. Pore formation in regulated cell death. EMBO J 2020; 39:e105753. [PMID: 33124082 PMCID: PMC7705454 DOI: 10.15252/embj.2020105753] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/13/2020] [Accepted: 10/06/2020] [Indexed: 12/21/2022] Open
Abstract
The discovery of alternative signaling pathways that regulate cell death has revealed multiple strategies for promoting cell death with diverse consequences at the tissue and organism level. Despite the divergence in the molecular components involved, membrane permeabilization is a common theme in the execution of regulated cell death. In apoptosis, the permeabilization of the outer mitochondrial membrane by BAX and BAK releases apoptotic factors that initiate the caspase cascade and is considered the point of no return in cell death commitment. Pyroptosis and necroptosis also require the perforation of the plasma membrane at the execution step, which involves Gasdermins in pyroptosis, and MLKL in the case of necroptosis. Although BAX/BAK, Gasdermins and MLKL share certain molecular features like oligomerization, they form pores in different cellular membranes via distinct mechanisms. Here, we compare and contrast how BAX/BAK, Gasdermins, and MLKL alter membrane permeability from a structural and biophysical perspective and discuss the general principles of membrane permeabilization in the execution of regulated cell death.
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Affiliation(s)
- Hector Flores‐Romero
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Uris Ros
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Ana J Garcia‐Saez
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
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27
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Sinha S, Ghosh Dastidar S. Shifting Polar Residues Across Primary Sequence Frames of Transmembrane Domains Calibrates Membrane Permeation Thermodynamics. Biochemistry 2020; 59:4353-4366. [PMID: 33136366 DOI: 10.1021/acs.biochem.0c00536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Permeation of the mitochondrial outer membrane (MOM) using the transmembrane domains (TMDs) is the key step of the Bcl-2 family of proteins to control apoptosis. The primary sequences of the TMDs of the family members like Bcl-xL, Bcl-2, Bak, etc. indicate the presence of charged residues at the C-terminal tip to be essential for drilling the membrane. However, Bax, a variant of the same family, is an exception, as the charged residues are shifted away from the tip by two positional frames in the primary sequence, but does it matter really? The free energy landscapes of membrane permeation, computed from a total of ∼13.3 μs of conformational sampling, show how such shifting of the amino acid frames in the primary sequence is correlated with the energy landscape that ensures the balance between membrane permeation and cytosolic population. Shifting the charged residues back to the terminal, in suitable mutants of Bax, proves the necessity of terminal charged residues by improving the insertion free energy but adds a high energy barrier unless some other polar residues are adjusted further. The difference in the TMDs of Bcl-xL and Bax is also reflected in their mechanism to drill the MOM-like anionic membrane; only Bax-TMD requires surface crowding to favorably shape the permeation landscape by weakening the bilayer integrity. So, this investigation suggests that such proteins can calibrate the free energy landscape of membrane permeation by adjusting the positions of the charged or polar residues in the primary sequence frames, a strategy analogous to the game of the "sliding tile puzzle" but played with primary sequence frames.
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Affiliation(s)
- Souvik Sinha
- Division of Bioinformatics, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata 700054, India
| | - Shubhra Ghosh Dastidar
- Division of Bioinformatics, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata 700054, India
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28
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Kong Z, Zhou C, Kang J, Tan Z. Comparison of the Effects of Nonprotein and Protein Nitrogen on Apoptosis and Autophagy of Rumen Epithelial Cells in Goats. Animals (Basel) 2020; 10:E2079. [PMID: 33182520 PMCID: PMC7696569 DOI: 10.3390/ani10112079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 11/05/2020] [Indexed: 12/04/2022] Open
Abstract
Protein nutrition is particularly important for the self-renewal processes of gastrointestinal epithelial cells. The self-renewal of cells is inseparable from the interaction between apoptosis and autophagy. However, there are few reports on the relationship between different nitrogen sources and apoptosis/autophagy. In this study, the relative protein expression of Bcl-2-associated X protein(Bax), caspase-3, and p62 was significantly higher (p < 0.05), while that of Bcl-xl, Bcl-2, Beclin1, and Microtuble-associated protein light chain 3 (LC3-II) was significantly lower (p < 0.05), in the NH4Cl group in comparison with the NH4Cl + 4-phenylbutyric acid (4PBA) group. In addition, the relative protein expression of Bax and caspase-3 was significantly higher (p < 0.05), while that of Bcl-2 and Bcl-xl was decreased significantly (p < 0.05), in the NH4Cl + 3-Methyladenine (3-MA) group and the methionine (Met) + 3-MA group in comparison with the NH4Cl group. Furthermore, the relative protein expression of Beclin1 and LC3B-II was significantly lower (p < 0.05), while that of p62 was significantly higher (p < 0.05), in the NH4Cl + Z-VAD-FMK group and the Met + Z-VAD-FMK group in comparison with the NH4Cl group. In conclusion, our results suggested that endoplasmic reticulum (ER) stress played a critical role in the crosstalk between apoptosis and autophagy induced by NH4Cl and Met. Autophagy had a more obvious ameliorative effect on ruminal epithelial cell apoptosis after treatment with nonprotein nitrogen than after treatment with protein nitrogen. These findings may reveal the molecular mechanism of apoptosis and autophagy induced by nonprotein nitrogen and protein nitrogen.
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Affiliation(s)
- Zhiwei Kong
- CAS Key Laboratory for Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (Z.K.); (J.K.); (Z.T.)
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
- College of Food Engineering and Biotechnology, Han Shan Normal University, Chaozhou 521041, China
| | - Chuanshe Zhou
- CAS Key Laboratory for Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (Z.K.); (J.K.); (Z.T.)
- Hunan Co-Innovation Center of Safety Animal Production, CICSAP, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha 410128, China
| | - Jinhe Kang
- CAS Key Laboratory for Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (Z.K.); (J.K.); (Z.T.)
- Hunan Co-Innovation Center of Safety Animal Production, CICSAP, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha 410128, China
| | - Zhiliang Tan
- CAS Key Laboratory for Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (Z.K.); (J.K.); (Z.T.)
- Hunan Co-Innovation Center of Safety Animal Production, CICSAP, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha 410128, China
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29
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Cowan AD, Smith NA, Sandow JJ, Kapp EA, Rustam YH, Murphy JM, Brouwer JM, Bernardini JP, Roy MJ, Wardak AZ, Tan IK, Webb AI, Gulbis JM, Smith BJ, Reid GE, Dewson G, Colman PM, Czabotar PE. BAK core dimers bind lipids and can be bridged by them. Nat Struct Mol Biol 2020; 27:1024-1031. [DOI: 10.1038/s41594-020-0494-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 07/31/2020] [Indexed: 12/27/2022]
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30
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Yan Z, Zhan J, Qi W, Lin J, Huang Y, Xue X, Pan X. The Protective Effect of Luteolin in Glucocorticoid-Induced Osteonecrosis of the Femoral Head. Front Pharmacol 2020; 11:1195. [PMID: 32903480 PMCID: PMC7435053 DOI: 10.3389/fphar.2020.01195] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/22/2020] [Indexed: 01/22/2023] Open
Abstract
Glucocorticoid-induced osteonecrosis of the femoral head (GIONFH) is a frequently occurring type of nontraumatic osteonecrosis. A failure of the timely treatment can eventually result in the collapse of the subchondral bone structure. Luteolin (Lut), a compound extracted from Rhizoma Drynariae, is reported to possess multiple pharmacological properties including anticancer, antioxidant, antiapoptosis, and antiinflammatory properties. However, whether Lut has a protective effect on the development of GIONFH remains unclear. In this study, we evaluated the effect of Lut on Dexamethasone (Dex)-induced STAT1/caspase3 pathway in vitro and evaluated GIONFH model in vivo. In vitro, Lut inhibited the upregulation of Dex-induced phospho-STAT1, cleaved caspase9, and cleaved caspase3. In addition, Lut inhibited Dex-induced expression of Bax and cytochrome c and increased the expression of B cell lymphoma-2(Bcl-2). In vivo, Lut decreased the proportion of empty lacunae in rats with GIONFH. Taken together, these findings indicate that Lut may have therapeutic potential in the treatment of GIONFH. Further, this effect might be achieved by suppressing mitochondrial apoptosis of osteoblasts via inhibition of STAT1 activity.
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Affiliation(s)
- Zijian Yan
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China.,Department of Orthopaedics, Zhejiang Provincial Key Laboratory of Orthpaedics, Wenzhou, China.,The Second School of Medicine, WenZhou Medical University, Wenzhou, China
| | - Jingdi Zhan
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China.,Department of Orthopaedics, Zhejiang Provincial Key Laboratory of Orthpaedics, Wenzhou, China.,The Second School of Medicine, WenZhou Medical University, Wenzhou, China
| | - Weihui Qi
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China.,Department of Orthopaedics, Zhejiang Provincial Key Laboratory of Orthpaedics, Wenzhou, China.,The Second School of Medicine, WenZhou Medical University, Wenzhou, China
| | - Jian Lin
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yijiang Huang
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xinghe Xue
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiaoyun Pan
- Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
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31
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Abstract
Mitochondria regulate major aspects of cell function by producing ATP, contributing to Ca2+ signaling, influencing redox potential, and controlling levels of reactive oxygen species. In this review, we will discuss recent findings that illustrate how mitochondrial respiration, Ca2+ handling, and production of reactive oxygen species affect vascular smooth muscle cell function during neointima formation. We will review mitochondrial fission/fusion as fundamental mechanisms for smooth muscle proliferation, migration, and metabolism and examine the role of mitochondrial mobility in cell migration. In addition, we will summarize novel aspects by which mitochondria regulate apoptosis.
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Affiliation(s)
- Isabella M Grumbach
- From the Abboud Cardiovascular Research Center, Division of Cardiovascular Medicine, Department of Internal Medicine (I.M.G., E.K.N.), University of Iowa, Iowa City.,Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center (I.M.G.), University of Iowa, Iowa City.,Iowa City VA Health Care System (I.M.G.)
| | - Emily K Nguyen
- From the Abboud Cardiovascular Research Center, Division of Cardiovascular Medicine, Department of Internal Medicine (I.M.G., E.K.N.), University of Iowa, Iowa City
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32
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Flores-Romero H, Ros U, García-Sáez AJ. A lipid perspective on regulated cell death. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2019; 351:197-236. [PMID: 32247580 DOI: 10.1016/bs.ircmb.2019.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lipids are fundamental to life as structural components of cellular membranes and for signaling. They are also key regulators of different cellular processes such as cell division, proliferation, and death. Regulated cell death (RCD) requires the engagement of lipids and lipid metabolism for the initiation and execution of its killing machinery. The permeabilization of lipid membranes is a hallmark of RCD that involves, for each kind of cell death, a unique lipid profile. While the permeabilization of the mitochondrial outer membrane allows the release of apoptotic factors to the cytosol during apoptosis, permeabilization of the plasma membrane facilitates the release of intracellular content in other nonapoptotic types of RCD like necroptosis and ferroptosis. Lipids and lipid membranes are important accessory molecules required for the activation of protein executors of cell death such as BAX in apoptosis and MLKL in necroptosis. Peroxidation of membrane phospholipids and the subsequent membrane destabilization is a prerequisite to ferroptosis. Here, we discuss how lipids are essential players in apoptosis, the most common form of RCD, and also their role in necroptosis and ferroptosis. Altogether, we aim to highlight the contribution of lipids and membrane dynamics in cell death regulation.
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Affiliation(s)
- Hector Flores-Romero
- Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Uris Ros
- Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Ana J García-Sáez
- Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.
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33
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The Incomplete Puzzle of the BCL2 Proteins. Cells 2019; 8:cells8101176. [PMID: 31569576 PMCID: PMC6830314 DOI: 10.3390/cells8101176] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 09/25/2019] [Accepted: 09/26/2019] [Indexed: 02/07/2023] Open
Abstract
The proteins of the BCL2 family are key players in multiple cellular processes, chief amongst them being the regulation of mitochondrial integrity and apoptotic cell death. These proteins establish an intricate interaction network that expands both the cytosol and the surface of organelles to dictate the cell fate. The complexity and unpredictability of the BCL2 interactome resides in the large number of family members and of interaction surfaces, as well as on their different behaviours in solution and in the membrane. Although our current structural knowledge of the BCL2 proteins has been proven therapeutically relevant, the precise structure of membrane-bound complexes and the regulatory effect that membrane lipids exert over these proteins remain key questions in the field. Here, we discuss the complexity of BCL2 interactome, the new insights, and the black matter in the field.
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34
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Lai Y, Kuo Y, Chiang Y. Identifying Protein Conformational Dynamics Using Spin‐label ESR. Chem Asian J 2019; 14:3981-3991. [DOI: 10.1002/asia.201900855] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/02/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Yei‐Chen Lai
- Department of Chemistry National Tsing Hua University Hsinchu 30013 Taiwan
- Department of Chemistry&Biochemistry University of California Santa Barbara CA 93106-9510 USA
| | - Yun‐Hsuan Kuo
- Department of Chemistry National Tsing Hua University Hsinchu 30013 Taiwan
| | - Yun‐Wei Chiang
- Department of Chemistry National Tsing Hua University Hsinchu 30013 Taiwan
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35
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健愉 冯, 玉山 朱, 陈 权, 凌 林, Jianyu F, Yushan Z, Quan C, Jialing L. [Physiological Function and Structural Basis of Bcl-2 Family Proteins]. ZHONGGUO XI BAO SHENG WU XUE XUE BAO 2019; 41:1477-1489. [PMID: 34249113 PMCID: PMC8265309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Apoptosis is an important biological process that plays a key role in the regulation of cell fate and homeostasis. The B-cell lymphoma-2 (Bcl-2) family proteins are important regulators of the apoptotic pathway, and their dysfunction is associated with a variety of diseases, including cancer, neurodegenerative and autoimmune diseases. In the past decade, a large number of research work on the physiological functions and atomic structures of Bcl-2 family proteins have been reported, which has deepened our understanding of the molecular mechanism and pathological significance of Bcl-2 family proteins. Recently, new drugs targeting different Bcl-2 proteins have been developed and used in clinics or tested in clinical trials. However, the complexity and diversity in functions and structures of Bcl-2 family have left many unsolved problems. This article summarizes current knowledge of the structure and function of Bcl-2 family proteins and discusses the pharmacological significance of Bcl-2 proteins as effective therapeutic targets.
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Affiliation(s)
| | | | | | - 林家 凌
- 俄克拉荷马大学健康科学中心生物化学与分子生物学系, 俄克拉何马城 73126-0901
| | - Feng Jianyu
- College of Life Sciences, Nankai University, Tianjin 300074, China
| | - Zhu Yushan
- College of Life Sciences, Nankai University, Tianjin 300074, China
| | - Chen Quan
- College of Life Sciences, Nankai University, Tianjin 300074, China
| | - Lin Jialing
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma 73126, USA
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36
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Zhou Y, Richards AM, Wang P. MicroRNA-221 Is Cardioprotective and Anti-fibrotic in a Rat Model of Myocardial Infarction. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 17:185-197. [PMID: 31261033 PMCID: PMC6606926 DOI: 10.1016/j.omtn.2019.05.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 05/21/2019] [Accepted: 05/21/2019] [Indexed: 01/22/2023]
Abstract
Reduced myocardial miR-221 expression is associated with severe cardiac fibrosis in heart failure patients. We aimed to demonstrate its mechanisms in cardioprotection and remodeling following myocardial infarction (MI). Using in vitro hypoxia and reoxygenation (H/R) of H9c2 and rat cardiac fibroblast (cFB) models, we found that miR-221 protects H9c2 through combined anti-apoptotic and anti-autophagic effects and cFB via anti-autophagic effects alone in H/R. It inhibits myofibroblast (myoFB) activation as indicated by lowering α-smooth muscle actin (α-SMA) expression, gel contraction, and collagen synthesis (Sircol assay). In vivo, following left coronary artery ligation (MI), rats were treated with miR-221 mimics (intravenous [i.v.], 1 mg/kg). With treatment, miR-221 increased by ∼15-fold in infarct and peri-infarct zones at day 2 post-MI. At days 7 and 30 post-MI, miR-221 reduced infarct size, fibrosis, and α-SMA+ cells in both infarct and remote myocardium. Left ventricle (LV) function was preserved as indicated by ejection fraction, infarct thickness, LV developed pressure, ±dP/dt, and end diastolic pressure. We demonstrated the anti-apoptotic and anti-autophagic effects were due to combined mechanisms of direct targeting on Bak1 and P53 and inhibition of phosphorylation at Ser46 and direct targeting on Ddit4, respectively. miR-221 enhances cardiomyocyte survival and protects cardiac function post-MI. It enhances cFB survival yet inhibits their activation, thus reducing adverse cardiac fibrosis.
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Affiliation(s)
- Yue Zhou
- Cardiovascular Research Institute, National University Health System, Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Arthur Mark Richards
- Cardiovascular Research Institute, National University Health System, Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; Christchurch Heart Institute, Department of Medicine, University of Otago, Christchurch, Christchurch, New Zealand
| | - Peipei Wang
- Cardiovascular Research Institute, National University Health System, Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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37
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Contribution of Mitochondrial Ion Channels to Chemo-Resistance in Cancer Cells. Cancers (Basel) 2019; 11:cancers11060761. [PMID: 31159324 PMCID: PMC6627730 DOI: 10.3390/cancers11060761] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 05/16/2019] [Accepted: 05/23/2019] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial ion channels are emerging oncological targets, as modulation of these ion-transporting proteins may impact on mitochondrial membrane potential, efficiency of oxidative phosphorylation and reactive oxygen production. In turn, these factors affect the release of cytochrome c, which is the point of no return during mitochondrial apoptosis. Many of the currently used chemotherapeutics induce programmed cell death causing damage to DNA and subsequent activation of p53-dependent pathways that finally leads to cytochrome c release from the mitochondrial inter-membrane space. The view is emerging, as summarized in the present review, that ion channels located in this organelle may account in several cases for the resistance that cancer cells can develop against classical chemotherapeutics, by preventing drug-induced apoptosis. Thus, pharmacological modulation of these channel activities might be beneficial to fight chemo-resistance of different types of cancer cells.
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38
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Bax to the future - A novel, high-yielding approach for purification and expression of full-length Bax protein for structural studies. Protein Expr Purif 2019; 158:20-26. [PMID: 30738180 DOI: 10.1016/j.pep.2019.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 01/18/2019] [Accepted: 02/05/2019] [Indexed: 01/27/2023]
Abstract
Mitochondria-mediated apoptosis (programmed cell death) involves a sophisticated signaling and regulatory network that is regulated by the Bcl-2 protein family. Members of this family have either pro- or anti-apoptotic functions. An important pro-apoptotic member of this family is the cytosolic Bax. This protein is crucial for the onset of apoptosis by perforating the mitochondrial outer membrane (MOM). This process can be seen as point of no return, since disintegration of the MOM leads to the release of apotogenic factors such as cytochrome c into the cytosol triggering the activation of caspases and subsequent apoptotic steps. Bax is able to interact with the MOM with both its termini, making it inherently difficult to express in E. coli. In this study, we present a novel approach to express and purify full-length Bax with significantly increased yields, when compared to the commonly applied strategy. Using a double fusion approach with an N-terminal GST-tag and a C-terminal Intein-CBD-tag, we were able to render both Bax termini inactive and prevent disruptive interactions from occurring during gene expression. By deploying an Intein-CBD-tag at the C-terminus we were further able to avoid the introduction of any artificial residues, hence ensuring the native like activity of the membrane-penetrating C-terminus of Bax. Further, by engineering a His6-tag to the C-terminus of the CBD-tag we greatly improved the robustness of the purification procedure. We report yields for pure, full-length Bax protein that are increased by an order of magnitude, when compared to commonly used Bax expression protocols.
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39
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Ader NR, Hoffmann PC, Ganeva I, Borgeaud AC, Wang C, Youle RJ, Kukulski W. Molecular and topological reorganizations in mitochondrial architecture interplay during Bax-mediated steps of apoptosis. eLife 2019; 8:40712. [PMID: 30714902 PMCID: PMC6361589 DOI: 10.7554/elife.40712] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 01/22/2019] [Indexed: 12/25/2022] Open
Abstract
During apoptosis, Bcl-2 proteins such as Bax and Bak mediate the release of pro-apoptotic proteins from the mitochondria by clustering on the outer mitochondrial membrane and thereby permeabilizing it. However, it remains unclear how outer membrane openings form. Here, we combined different correlative microscopy and electron cryo-tomography approaches to visualize the effects of Bax activity on mitochondria in human cells. Our data show that Bax clusters localize near outer membrane ruptures of highly variable size. Bax clusters contain structural elements suggesting a higher order organization of their components. Furthermore, unfolding of inner membrane cristae is coupled to changes in the supramolecular assembly of ATP synthases, particularly pronounced at membrane segments exposed to the cytosol by ruptures. Based on our results, we propose a comprehensive model in which molecular reorganizations of the inner membrane and sequestration of outer membrane components into Bax clusters interplay in the formation of outer membrane ruptures. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- Nicholas R Ader
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Patrick C Hoffmann
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Iva Ganeva
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Alicia C Borgeaud
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Chunxin Wang
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Richard J Youle
- Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Wanda Kukulski
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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40
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Abstract
The Bcl-2 family of proteins regulates mitochondrial outer membrane permeability thereby making life or death decisions for cells. Most of Bcl-2 proteins contain hydrophobic regions that are embedded in intracellular membranes such as mitochondria. These membrane proteins are difficult to express and purify thereby preluding biochemical and biophysical characterizations. Here, we describe a photocrosslinking approach based on in vitro synthesis of Bcl-2 proteins with photoreactive amino acid analogs incorporated at specific locations. These photoreactive proteins are reconstituted into liposomal membranes with defined phospholipids or mitochondrial membranes isolated from animals, and their interactions with other Bcl-2 proteins are detected by photocrosslinking.
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41
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Topology of active, membrane-embedded Bax in the context of a toroidal pore. Cell Death Differ 2018; 25:1717-1731. [PMID: 30185826 DOI: 10.1038/s41418-018-0184-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/20/2018] [Accepted: 05/21/2018] [Indexed: 01/18/2023] Open
Abstract
Bax is a Bcl-2 protein critical for apoptosis induction. In healthy cells, Bax is mostly a monomeric, cytosolic protein, while upon apoptosis initiation it inserts into the outer mitochondrial membrane, oligomerizes, and forms pores that release proapoptotic factors like Cytochrome c into the cytosol. The structures of active Bax and its homolog Bak are only partially understood and the topology of the proteins with respect to the membrane bilayer is controversially described in the literature. Here, we systematically review and examine the protein-membrane, protein-water, and protein-protein contacts of the nine helices of active Bax and Bak, and add a new set of topology data obtained by fluorescence and EPR methods. We conclude based on the consistent part of the datasets that the core/dimerization domain of Bax (Bak) is water exposed with only helices 4 and 5 in membrane contact, whereas the piercing/latch domain is in peripheral membrane contact, with helix 9 being transmembrane. Among the available structural models, those considering the dimerization/core domain at the rim of a toroidal pore are the most plausible to describe the active state of the proteins, although the structural flexibility of the piercing/latch domain does not allow unambiguous discrimination between the existing models.
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42
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Proteomic analysis of monolayer-integrated proteins on lipid droplets identifies amphipathic interfacial α-helical membrane anchors. Proc Natl Acad Sci U S A 2018; 115:E8172-E8180. [PMID: 30104359 DOI: 10.1073/pnas.1807981115] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Despite not spanning phospholipid bilayers, monotopic integral proteins (MIPs) play critical roles in organizing biochemical reactions on membrane surfaces. Defining the structural basis by which these proteins are anchored to membranes has been hampered by the paucity of unambiguously identified MIPs and a lack of computational tools that accurately distinguish monolayer-integrating motifs from bilayer-spanning transmembrane domains (TMDs). We used quantitative proteomics and statistical modeling to identify 87 high-confidence candidate MIPs in lipid droplets, including 21 proteins with predicted TMDs that cannot be accommodated in these monolayer-enveloped organelles. Systematic cysteine-scanning mutagenesis showed the predicted TMD of one candidate MIP, DHRS3, to be a partially buried amphipathic α-helix in both lipid droplet monolayers and the cytoplasmic leaflet of endoplasmic reticulum membrane bilayers. Coarse-grained molecular dynamics simulations support these observations, suggesting that this helix is most stable at the solvent-membrane interface. The simulations also predicted similar interfacial amphipathic helices when applied to seven additional MIPs from our dataset. Our findings suggest that interfacial helices may be a common motif by which MIPs are integrated into membranes, and provide high-throughput methods to identify and study MIPs.
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43
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Lai YC, Li CC, Sung TC, Chang CW, Lan YJ, Chiang YW. The role of cardiolipin in promoting the membrane pore-forming activity of BAX oligomers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:268-280. [PMID: 29958826 DOI: 10.1016/j.bbamem.2018.06.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/17/2018] [Accepted: 06/22/2018] [Indexed: 01/31/2023]
Abstract
BCL-2-associated X (BAX) protein acts as a gatekeeper in regulating mitochondria-dependent apoptosis. Under cellular stress, BAX becomes activated and transforms into a lethal oligomer that causes mitochondrial outer membrane permeabilization (MOMP). Previous studies have identified several structural features of the membrane-associated BAX oligomer; they include the formation of the BH3-in-groove dimer, the collapse of the helical hairpin α5-α6, and the membrane insertion of α9 helix. However, it remains unclear as to the role of lipid environment in determining the conformation and the pore-forming activity of the BAX oligomers. Here we study molecular details of the membrane-associated BAX in various lipid environments using fluorescence and ESR techniques. We identify the inactive versus active forms of membrane-associated BAX, only the latter of which can induce stable and large membrane pores that are sufficient in size to pass apoptogenic factors. We reveal that the presence of CL is crucial to promoting the association between BAX dimers, hence the active oligomers. Without the presence of CL, BAX dimers assemble into an inactive oligomer that lacks the ability to form stable pores in the membrane. This study suggests an important role of CL in determining the formation of active BAX oligomers.
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Affiliation(s)
- Yei-Chen Lai
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chieh-Chin Li
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Tai-Ching Sung
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chia-Wei Chang
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yu-Jing Lan
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yun-Wei Chiang
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
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44
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Edlich F. BCL-2 proteins and apoptosis: Recent insights and unknowns. Biochem Biophys Res Commun 2018; 500:26-34. [DOI: 10.1016/j.bbrc.2017.06.190] [Citation(s) in RCA: 233] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 06/30/2017] [Indexed: 01/08/2023]
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45
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New limits of sensitivity of site-directed spin labeling electron paramagnetic resonance for membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:841-853. [DOI: 10.1016/j.bbamem.2017.12.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 11/27/2017] [Accepted: 12/09/2017] [Indexed: 01/27/2023]
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46
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Fricker M, Tolkovsky AM, Borutaite V, Coleman M, Brown GC. Neuronal Cell Death. Physiol Rev 2018; 98:813-880. [PMID: 29488822 PMCID: PMC5966715 DOI: 10.1152/physrev.00011.2017] [Citation(s) in RCA: 677] [Impact Index Per Article: 112.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/23/2017] [Accepted: 07/10/2017] [Indexed: 02/07/2023] Open
Abstract
Neuronal cell death occurs extensively during development and pathology, where it is especially important because of the limited capacity of adult neurons to proliferate or be replaced. The concept of cell death used to be simple as there were just two or three types, so we just had to work out which type was involved in our particular pathology and then block it. However, we now know that there are at least a dozen ways for neurons to die, that blocking a particular mechanism of cell death may not prevent the cell from dying, and that non-neuronal cells also contribute to neuronal death. We review here the mechanisms of neuronal death by intrinsic and extrinsic apoptosis, oncosis, necroptosis, parthanatos, ferroptosis, sarmoptosis, autophagic cell death, autosis, autolysis, paraptosis, pyroptosis, phagoptosis, and mitochondrial permeability transition. We next explore the mechanisms of neuronal death during development, and those induced by axotomy, aberrant cell-cycle reentry, glutamate (excitoxicity and oxytosis), loss of connected neurons, aggregated proteins and the unfolded protein response, oxidants, inflammation, and microglia. We then reassess which forms of cell death occur in stroke and Alzheimer's disease, two of the most important pathologies involving neuronal cell death. We also discuss why it has been so difficult to pinpoint the type of neuronal death involved, if and why the mechanism of neuronal death matters, the molecular overlap and interplay between death subroutines, and the therapeutic implications of these multiple overlapping forms of neuronal death.
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Affiliation(s)
- Michael Fricker
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Aviva M Tolkovsky
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Vilmante Borutaite
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Michael Coleman
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Guy C Brown
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
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47
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Ugarte-Uribe B, García-Sáez AJ. Apoptotic foci at mitochondria: in and around Bax pores. Philos Trans R Soc Lond B Biol Sci 2018. [PMID: 28630156 DOI: 10.1098/rstb.2016.0217] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The permeabilization of the mitochondrial outer membrane by Bax and Bak during apoptosis is considered a key step and a point of no return in the signalling pathway. It is always closely related to the reorganization of mitochondrial cristae that frees cytochrome c to the intermembrane space and to massive mitochondrial fragmentation mediated by the dynamin-like protein Drp1. Despite multiple evidence in favour of a functional link between these processes, the molecular mechanisms that connect them and their relevance for efficient apoptosis signalling remain obscure. In this review, we discuss recent progress on our understanding of how Bax forms pores in the context of Drp1-stabilized signalling platforms at apoptotic foci in mitochondria.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.
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Affiliation(s)
- Begoña Ugarte-Uribe
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe Seyler Straße 4, 72076 Tübingen, Germany.,Biofisika Institute (UPV/EHU, CSIC), Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Ana J García-Sáez
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe Seyler Straße 4, 72076 Tübingen, Germany .,Max Planck Institute for Intelligent Systems, Stuttgart, Germany
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48
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Uren RT, Iyer S, Kluck RM. Pore formation by dimeric Bak and Bax: an unusual pore? Philos Trans R Soc Lond B Biol Sci 2018. [PMID: 28630157 DOI: 10.1098/rstb.2016.0218] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Apoptotic cell death via the mitochondrial pathway occurs in all vertebrate cells and requires the formation of pores in the mitochondrial outer membrane. Two Bcl-2 protein family members, Bak and Bax, form these pores during apoptosis, and how they do so has been investigated for the last two decades. Many of the conformation changes that occur during their transition to pore-forming proteins have now been delineated. Notably, biochemical, biophysical and structural studies indicate that symmetric homodimers are the basic unit of pore formation. Each dimer contains an extended hydrophobic surface that lies on the outer membrane, and is anchored at either end by a transmembrane domain. Membrane-remodelling events such as positive membrane curvature have been reported to accompany apoptotic pore formation, suggesting Bak and Bax form lipidic pores rather than proteinaceous pores. However, it remains unclear how symmetric dimers assemble to porate the membrane. Here, we review how clusters of dimers and their lipid-mediated interactions provide a molecular explanation for the heterogeneous assemblies of Bak and Bax observed during apoptosis.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.
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Affiliation(s)
- Rachel T Uren
- Molecular Genetics of Cancer Division, The Walter and Eliza Hall Institute of Medical Research, The University of Melbourne, 1G Royal Parade, Parkville, Victoria 3052, Australia.,Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - Sweta Iyer
- Molecular Genetics of Cancer Division, The Walter and Eliza Hall Institute of Medical Research, The University of Melbourne, 1G Royal Parade, Parkville, Victoria 3052, Australia.,Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, Victoria 3052, Australia
| | - Ruth M Kluck
- Molecular Genetics of Cancer Division, The Walter and Eliza Hall Institute of Medical Research, The University of Melbourne, 1G Royal Parade, Parkville, Victoria 3052, Australia .,Department of Medical Biology, The University of Melbourne, 1G Royal Parade, Parkville, Victoria 3052, Australia
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49
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Raltchev K, Pipercevic J, Hagn F. Production and Structural Analysis of Membrane-Anchored Proteins in Phospholipid Nanodiscs. Chemistry 2018; 24:5493-5499. [DOI: 10.1002/chem.201800812] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Indexed: 01/03/2023]
Affiliation(s)
- Kolio Raltchev
- Bavarian NMR Center at the Department of Chemistry and Institute for Advanced Study; Technical University of Munich; Lichtenbergstrasse 4 85747 Garching Germany
- Institute of Structural Biology; Helmholtz Zentrum München; Ingolstädter Landstrasse 1 85764 Neuherberg Germany
| | - Joka Pipercevic
- Bavarian NMR Center at the Department of Chemistry and Institute for Advanced Study; Technical University of Munich; Lichtenbergstrasse 4 85747 Garching Germany
- Institute of Structural Biology; Helmholtz Zentrum München; Ingolstädter Landstrasse 1 85764 Neuherberg Germany
| | - Franz Hagn
- Bavarian NMR Center at the Department of Chemistry and Institute for Advanced Study; Technical University of Munich; Lichtenbergstrasse 4 85747 Garching Germany
- Institute of Structural Biology; Helmholtz Zentrum München; Ingolstädter Landstrasse 1 85764 Neuherberg Germany
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50
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Membrane insertion of the BAX core, but not latch domain, drives apoptotic pore formation. Sci Rep 2017; 7:16259. [PMID: 29176554 PMCID: PMC5701199 DOI: 10.1038/s41598-017-16384-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 10/31/2017] [Indexed: 12/31/2022] Open
Abstract
Despite intensive research effort, how the paradigmatic proapoptotic protein BAX forms lethal apoptotic pores at the mitochondrial outer membrane (MOM) remains incompletely understood. Here, we used biophysical tools and minimalist model systems to identify the specific regions in BAX driving apoptotic pore formation, and to gain more insight into underlying mechanisms. Fluorescence mapping revealed that fully active BAX adopts a BH3-in-groove dimeric conformation in MOM-like membranes, with BAX α4-α5 helices belonging to its core domain inserting deeper into the membrane lipid bilayer than BAX α6-α8 helices belonging to its latch domain. In our reconstituted systems, antiapoptotic BCLXL formed canonical heterodimeric BH3-in-groove complexes with BAX, and blocked membrane insertion of BAX core α4-α5 helices, but not BAX latch α6-α8 helices. Moreover, poly(ethylene glycol) (PEG) conjugation (PEGylation) at multiple individual sites along the BAX core, but not latch domain, potently inhibited BAX pore-forming activity. Additional combined computational and experimental evidence revealed that the BAX core α5 helix displays a bilayer-destabilizing membrane interaction mode that is absent in BAX latch α6-α8 helices. Based on this collective set of evidence, we propose that membrane insertion of the BAX core, but not latch domain, is critical for BAX apoptotic pore formation.
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