1
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Musharaf Hossain M, Alinapon CV, Todd CD, Wei Y, Bonham-Smith PC. The Plasmodiophora brassicae Golgi-localized UPF0016 protein PbGDT1 mediates calcium but not manganese transport in yeast and Nicotiana benthamiana. Fungal Genet Biol 2024; 172:103896. [PMID: 38663635 DOI: 10.1016/j.fgb.2024.103896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/11/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
Manganese and calcium homeostasis and signalling, in eukaryotic organisms, are regulated through membrane located pumps, channels and exchangers, including the Mn2+/Ca2+ uncharacterized protein family 0016 (UPF0016). Here we show that Plasmodiophora brassicae PbGDT1 is a member of the UPF0016 and an ortholog of Saccharomyces cerevisiae Gdt1p (GCR Dependent Translation Factor 1) protein involved in manganese homeostasis as well as the calcium mediated stress response in yeast. PbGDT1 complemented the ScGdt1p and ScPMR1 (Ca2+ ATPase) double null mutant under elevated calcium stress but not under elevated manganese conditions. In both yeast and Nicotiana benthamiana, PbGDT1 localizes to the Golgi apparatus, with additional ER association in N. benthamiana. Expression of PbGDT1 in N. benthamiana, suppresses BAX-triggered cell death, further highlighting the importance of calcium homeostasis in maintaining cell physiology and integrity in a stress environment.
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Affiliation(s)
- Md Musharaf Hossain
- Department of Biology, University of Saskatchewan, Saskatoon S7N5E2, Saskatchewan, Canada
| | | | - Christopher D Todd
- Department of Biology, University of Saskatchewan, Saskatoon S7N5E2, Saskatchewan, Canada
| | - Yangdou Wei
- Department of Biology, University of Saskatchewan, Saskatoon S7N5E2, Saskatchewan, Canada
| | - Peta C Bonham-Smith
- Department of Biology, University of Saskatchewan, Saskatoon S7N5E2, Saskatchewan, Canada.
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2
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Strížová A, Šmátralová P, Chovančíková P, Machala Z, Polčic P. Defects in Mitochondrial Functions Affect the Survival of Yeast Cells Treated with Non-Thermal Plasma. Int J Mol Sci 2023; 24:ijms24119391. [PMID: 37298346 DOI: 10.3390/ijms24119391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/14/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Exposure of living cells to non-thermal plasma produced in various electrical discharges affects cell physiology and often results in cell death. Even though plasma-based techniques have started finding practical applications in biotechnology and medicine, the molecular mechanisms of interaction of cells with plasma remain poorly understood. In this study, the involvement of selected cellular components or pathways in plasma-induced cell killing was studied employing yeast deletion mutants. The changes in yeast sensitivity to plasma-activated water were observed in mutants with the defect in mitochondrial functions, including transport across the outer mitochondrial membrane (∆por1), cardiolipin biosynthesis (∆crd1, ∆pgs1), respiration (ρ0) and assumed signaling to the nucleus (∆mdl1, ∆yme1). Together these results indicate that mitochondria play an important role in plasma-activated water cell killing, both as the target of the damage and the participant in the damage signaling, which may lead to the induction of cell protection. On the other hand, our results show that neither mitochondria-ER contact sites, UPR, autophagy, nor proteasome play a major role in the protection of yeast cells from plasma-induced damage.
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Affiliation(s)
- Anna Strížová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina CH1, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Paulína Šmátralová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina CH1, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Petra Chovančíková
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina CH1, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Zdenko Machala
- Division of Environmental Physics, Faculty of Mathematics, Physics, and Informatics, Comenius University in Bratislava, Mlynská dolina F2, 84248 Bratislava, Slovakia
| | - Peter Polčic
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina CH1, Ilkovičova 6, 84215 Bratislava, Slovakia
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3
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Lebeaupin C, Blanc M, Vallée D, Keller H, Bailly-Maitre B. BAX inhibitor-1: between stress and survival. FEBS J 2020; 287:1722-1736. [PMID: 31841271 DOI: 10.1111/febs.15179] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/18/2019] [Accepted: 12/13/2019] [Indexed: 12/13/2022]
Abstract
Cellular gatekeepers are essential to maintain order within a cell and anticipate signals of stress to promote survival. BCL2 associated X, apoptosis regulator (BAX) inhibitor-1 (BI-1), also named transmembrane BAX inhibitor motif containing-6, is a highly conserved endoplasmic reticulum (ER) transmembrane protein. Originally identified as an inhibitor of BAX-induced apoptosis, its pro-survival properties have been expanded to include functions targeted against ER stress, calcium imbalance, reactive oxygen species accumulation, and metabolic dysregulation. Nevertheless, the structural biology and biochemical mechanism of action of BI-1 are still under debate. BI-1 has been implicated in several diseases, including chronic liver disease, diabetes, ischemia/reperfusion injury, neurodegeneration, and cancer. While most studies have demonstrated a beneficial role for BI-1 in the ubiquitous maintenance of cellular homeostasis, its expression in cancer cells seems most often to contribute to tumorigenesis and metastasis. Here, we summarize what is known about BI-1 and encourage future studies on BI-1's contribution to cellular life and death decisions to advocate its potential as a target for drug development and other therapeutic strategies.
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Affiliation(s)
- Cynthia Lebeaupin
- INSERM U1065, C3M, Université Côte d'Azur, Nice, France.,Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.,Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Marina Blanc
- INSERM U1065, C3M, Université Côte d'Azur, Nice, France
| | | | - Harald Keller
- INRA1355-CNRS7254, Université Côte d'Azur, Sophia Antipolis, France
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4
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Guo G, Xu M, Chang Y, Luyten T, Seitaj B, Liu W, Zhu P, Bultynck G, Shi L, Quick M, Liu Q. Ion and pH Sensitivity of a TMBIM Ca 2+ Channel. Structure 2019; 27:1013-1021.e3. [PMID: 30930064 PMCID: PMC6560632 DOI: 10.1016/j.str.2019.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 01/25/2019] [Accepted: 02/28/2019] [Indexed: 12/12/2022]
Abstract
The anti-apoptotic transmembrane Bax inhibitor motif (TMBIM) containing protein family regulates Ca2+ homeostasis, cell death, and the progression of diseases including cancers. The recent crystal structures of the TMBIM homolog BsYetJ reveal a conserved Asp171-Asp195 dyad that is proposed in regulating a pH-dependent Ca2+ translocation. Here we show that BsYetJ mediates Ca2+ fluxes in permeabilized mammalian cells, and its interaction with Ca2+ is sensitive to protons and other cations. We report crystal structures of BsYetJ in additional states, revealing the flexibility of the dyad in a closed state and a pore-opening mechanism. Functional studies show that the dyad is responsible for both Ca2+ affinity and pH dependence. Computational simulations suggest that protonation of Asp171 weakens its interaction with Arg60, leading to an open state. Our integrated analysis provides insights into the regulation of the BsYetJ Ca2+ channel that may inform understanding of human TMBIM proteins regarding their roles in cell death and diseases.
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Affiliation(s)
- Gongrui Guo
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA; NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Min Xu
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, MA 21224, USA
| | - Yanqi Chang
- New York Consortium on Membrane Protein Structure, New York Structural Biology Center, New York, NY 10027, USA
| | - Tomas Luyten
- Laboratory Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49 3000 Leuven, Belgium
| | - Bruno Seitaj
- Laboratory Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49 3000 Leuven, Belgium
| | - Wu Liu
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA; NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Ping Zhu
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Geert Bultynck
- Laboratory Molecular and Cellular Signaling, Department Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49 3000 Leuven, Belgium
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Unit, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, MA 21224, USA.
| | - Matthias Quick
- Department of Psychiatry, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA.
| | - Qun Liu
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA; NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA.
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5
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Carrara G, Parsons M, Saraiva N, Smith GL. Golgi anti-apoptotic protein: a tale of camels, calcium, channels and cancer. Open Biol 2018; 7:rsob.170045. [PMID: 28469007 PMCID: PMC5451544 DOI: 10.1098/rsob.170045] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 04/10/2017] [Indexed: 12/11/2022] Open
Abstract
Golgi anti-apoptotic protein (GAAP), also known as transmembrane Bax inhibitor-1 motif-containing 4 (TMBIM4) or Lifeguard 4 (Lfg4), shares remarkable amino acid conservation with orthologues throughout eukaryotes, prokaryotes and some orthopoxviruses, suggesting a highly conserved function. GAAPs regulate Ca2+ levels and fluxes from the Golgi and endoplasmic reticulum, confer resistance to a broad range of apoptotic stimuli, promote cell adhesion and migration via the activation of store-operated Ca2+ entry, are essential for the viability of human cells, and affect orthopoxvirus virulence. GAAPs are oligomeric, multi-transmembrane proteins that are resident in Golgi membranes and form cation-selective ion channels that may explain the multiple functions of these proteins. Residues contributing to the ion-conducting pore have been defined and provide the first clues about the mechanistic link between these very different functions of GAAP. Although GAAPs are naturally oligomeric, they can also function as monomers, a feature that distinguishes them from other virus-encoded ion channels that must oligomerize for function. This review summarizes the known functions of GAAPs and discusses their potential importance in disease.
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Affiliation(s)
- Guia Carrara
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Maddy Parsons
- Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Nuno Saraiva
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK .,CBIOS, Universidade Lusófona Research Centre for Biosciences and Health Technologies, Campo Grande 376, Lisbon 1749-024, Portugal
| | - Geoffrey L Smith
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
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6
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Huang E, Qu D, Huang T, Rizzi N, Boonying W, Krolak D, Ciana P, Woulfe J, Klein C, Slack RS, Figeys D, Park DS. PINK1-mediated phosphorylation of LETM1 regulates mitochondrial calcium transport and protects neurons against mitochondrial stress. Nat Commun 2017; 8:1399. [PMID: 29123128 PMCID: PMC5680261 DOI: 10.1038/s41467-017-01435-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 09/18/2017] [Indexed: 01/04/2023] Open
Abstract
Mutations in PTEN-induced kinase 1 (PINK1) result in a recessive familial form of Parkinson’s disease (PD). PINK1 loss is associated with mitochondrial Ca2+ mishandling, mitochondrial dysfunction, as well as increased neuronal vulnerability. Here we demonstrate that PINK1 directly interacts with and phosphorylates LETM1 at Thr192 in vitro. Phosphorylated LETM1 or the phospho-mimetic LETM1-T192E increase calcium release in artificial liposomes and facilitates calcium transport in intact mitochondria. Expression of LETM1-T192E but not LETM1-wild type (WT) rescues mitochondrial calcium mishandling in PINK1-deficient neurons. Expression of both LETM1-WT and LETM1-T192E protects neurons against MPP+–MPTP-induced neuronal death in PINK1 WT neurons, whereas only LETM1-T192E protects neurons under conditions of PINK1 loss. Our findings delineate a mechanism by which PINK1 regulates mitochondrial Ca2+ level through LETM1 and suggest a model by which PINK1 loss leads to deficient phosphorylation of LETM1 and impaired mitochondrial Ca2+ transport.. Mutations in the mitochondrial kinase PINK1 result in familial Parkinson’s disease. Here the authors show that LETM1, a mitochondrial inner membrane protein, is a substrate of PINK1 that regulates Ca2+ handling in mitochondria in response to mitochondrial toxins.
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Affiliation(s)
- En Huang
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Dianbo Qu
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Tianwen Huang
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Nicoletta Rizzi
- Center of Excellence on Neurodegenerative Diseases, Department of Pharmacological Sciences, University of Milan, Via Balzaretti 9, 20133, Milan, Italy
| | - Wassamon Boonying
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Dorothy Krolak
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Paolo Ciana
- Center of Excellence on Neurodegenerative Diseases, Department of Oncology and Hemato-Oncology, University of Milan, Via Balzaretti 9, 20133, Milan, Italy
| | - John Woulfe
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute and Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Christine Klein
- Institute of Neurogenetics, University of Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany
| | - Ruth S Slack
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - Daniel Figeys
- Department of Biochemistry, Microbiology and Immunology, Department of Chemistry and Biomolecular Sciences, and Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON, Canada, K1H 8M5
| | - David S Park
- University of Ottawa Brain and Mind Research Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada, K1H 8M5.
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7
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Liu Q. TMBIM-mediated Ca 2+ homeostasis and cell death. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:850-857. [PMID: 28064000 DOI: 10.1016/j.bbamcr.2016.12.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 12/22/2016] [Accepted: 12/22/2016] [Indexed: 11/25/2022]
Abstract
Ca2+ is a ubiquitous intracellular messenger that regulates numerous physiological activities in humans, animals, plants, and bacteria. Cytosolic Ca2+ is kept at a low level, but subcellular organelles such as the endoplasmic reticulum (ER) and Golgi apparatus maintain high-concentration Ca2+ stores. Under resting conditions, store Ca2+ homeostasis is dynamically regulated to equilibrate between active Ca2+ uptake and passive Ca2+ leak processes. The evolutionarily conserved Transmembrane BAX Inhibitor-1 Motif-containing (TMBIM) proteins mediate Ca2+ homeostasis and cell death. This review focuses on recent advances in functional and structural analysis of TMBIM proteins in regulation of the two related functions. The roles of TMBIM proteins in pathogen infection and cancer are also discussed with prospects for treatment. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Qun Liu
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
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8
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Carrara G, Saraiva N, Parsons M, Byrne B, Prole DL, Taylor CW, Smith GL. Golgi anti-apoptotic proteins are highly conserved ion channels that affect apoptosis and cell migration. J Biol Chem 2015; 290:11785-801. [PMID: 25713081 PMCID: PMC4416878 DOI: 10.1074/jbc.m115.637306] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Indexed: 12/03/2022] Open
Abstract
Golgi anti-apoptotic proteins (GAAPs) are multitransmembrane proteins that are expressed in the Golgi apparatus and are able to homo-oligomerize. They are highly conserved throughout eukaryotes and are present in some prokaryotes and orthopoxviruses. Within eukaryotes, GAAPs regulate the Ca2+ content of intracellular stores, inhibit apoptosis, and promote cell adhesion and migration. Data presented here demonstrate that purified viral GAAPs (vGAAPs) and human Bax inhibitor 1 form ion channels and that vGAAP from camelpox virus is selective for cations. Mutagenesis of vGAAP, including some residues conserved in the recently solved structure of a related bacterial protein, BsYetJ, altered the conductance (E207Q and D219N) and ion selectivity (E207Q) of the channel. Mutation of residue Glu-207 or -178 reduced the effects of GAAP on cell migration and adhesion without affecting protection from apoptosis. In contrast, mutation of Asp-219 abrogated the anti-apoptotic activity of GAAP but not its effects on cell migration and adhesion. These results demonstrate that GAAPs are ion channels and define residues that contribute to the ion-conducting pore and affect apoptosis, cell adhesion, and migration independently.
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Affiliation(s)
- Guia Carrara
- From the Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
| | - Nuno Saraiva
- From the Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom
| | - Maddy Parsons
- the Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom
| | - Bernadette Byrne
- the Division of Molecular Biosciences, Imperial College London, London SW7 2AZ, United Kingdom, and
| | - David L Prole
- the Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom,
| | - Colin W Taylor
- the Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom,
| | - Geoffrey L Smith
- From the Department of Pathology, University of Cambridge, Cambridge CB2 1QP, United Kingdom,
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9
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Bultynck G, Kiviluoto S, Methner A. Bax Inhibitor-1 Is Likely a pH-Sensitive Calcium Leak Channel, Not a H+/Ca2+ Exchanger. Sci Signal 2014; 7:pe22. [DOI: 10.1126/scisignal.2005764] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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10
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Akl H, Vervloessem T, Kiviluoto S, Bittremieux M, Parys JB, De Smedt H, Bultynck G. A dual role for the anti-apoptotic Bcl-2 protein in cancer: mitochondria versus endoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2240-52. [PMID: 24768714 DOI: 10.1016/j.bbamcr.2014.04.017] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 12/14/2022]
Abstract
Anti-apoptotic Bcl-2 contributes to cancer formation and progression by promoting the survival of altered cells. Hence, it is a prime target for novel specific anti-cancer therapeutics. In addition to its canonical anti-apoptotic role, Bcl-2 has an inhibitory effect on cell-cycle progression. Bcl-2 acts at two different intracellular compartments, the mitochondria and the endoplasmic reticulum (ER). At the mitochondria, Bcl-2 via its hydrophobic cleft scaffolds the Bcl-2-homology (BH) domain 3 (BH3) of pro-apoptotic Bcl-2-family members. Small molecules (like BH3 mimetics) can disrupt this interaction, resulting in apoptotic cell death in cancer cells. At the ER, Bcl-2 modulates Ca(2+) signaling, thereby promoting proliferation while increasing resistance to apoptosis. Bcl-2 at the ER acts via its N-terminal BH4 domain, which directly binds and inhibits the inositol 1,4,5-trisphosphate receptor (IP3R), the main intracellular Ca(2+)-release channel. Tools targeting the BH4 domain of Bcl-2 reverse Bcl-2's inhibitory action on IP3Rs and trigger pro-apoptotic Ca(2+) signaling in cancer B-cells, including chronic lymphocytic leukemia (CLL) cells and diffuse large B-cell lymphoma (DLBCL) cells. The sensitivity of DLBCL cells to BH4-domain targeting tools strongly correlated with the expression levels of the IP3R2 channel, the IP3R isoform with the highest affinity for IP3. Interestingly, bio-informatic analysis of a database of primary CLL patient cells also revealed a transcriptional upregulation of IP3R2. Finally, this review proposes a model, in which cancer cell survival depends on Bcl-2 at the mitochondria and/or the ER. This dependence likely will have an impact on their responses to BH3-mimetic drugs and BH4-domain targeting tools. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Haidar Akl
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
| | - Tamara Vervloessem
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Santeri Kiviluoto
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Mart Bittremieux
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Humbert De Smedt
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Molecular and Cellular Medicine, Campus Gasthuisberg, O/N-I, Bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
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11
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Ivanova H, Vervliet T, Missiaen L, Parys JB, De Smedt H, Bultynck G. Inositol 1,4,5-trisphosphate receptor-isoform diversity in cell death and survival. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2164-83. [PMID: 24642269 DOI: 10.1016/j.bbamcr.2014.03.007] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/06/2014] [Accepted: 03/09/2014] [Indexed: 01/22/2023]
Abstract
Cell-death and -survival decisions are critically controlled by intracellular Ca(2+) homeostasis and dynamics at the level of the endoplasmic reticulum (ER). Inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) play a pivotal role in these processes by mediating Ca(2+) flux from the ER into the cytosol and mitochondria. Hence, it is clear that many pro-survival and pro-death signaling pathways and proteins affect Ca(2+) signaling by directly targeting IP3R channels, which can happen in an IP3R-isoform-dependent manner. In this review, we will focus on how the different IP3R isoforms (IP3R1, IP3R2 and IP3R3) control cell death and survival. First, we will present an overview of the isoform-specific regulation of IP3Rs by cellular factors like IP3, Ca(2+), Ca(2+)-binding proteins, adenosine triphosphate (ATP), thiol modification, phosphorylation and interacting proteins, and of IP3R-isoform specific expression patterns. Second, we will discuss the role of the ER as a Ca(2+) store in cell death and survival and how IP3Rs and pro-survival/pro-death proteins can modulate the basal ER Ca(2+) leak. Third, we will review the regulation of the Ca(2+)-flux properties of the IP3R isoforms by the ER-resident and by the cytoplasmic proteins involved in cell death and survival as well as by redox regulation. Hence, we aim to highlight the specific roles of the various IP3R isoforms in cell-death and -survival signaling. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Hristina Ivanova
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Tim Vervliet
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Ludwig Missiaen
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Humbert De Smedt
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium.
| | - Geert Bultynck
- KU Leuven Lab. of Molecular and Cellular Signaling, Dept. of Cellular and Molecular Medicine, Campus Gasthuisberg O&N I Box 802, Herestraat 49, BE-3000 Leuven, Belgium.
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12
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B L, R.K Y, G.S J, H.-R K, H.-J C. The characteristics of Bax inhibitor-1 and its related diseases. Curr Mol Med 2014; 14:603-15. [PMID: 24894176 PMCID: PMC4083451 DOI: 10.2174/1566524014666140603101113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 10/01/2013] [Accepted: 11/24/2013] [Indexed: 11/28/2022]
Abstract
Bax inhibitor-1 (BI-1) is an evolutionarily-conserved endoplasmic reticulum protein. The expression of BI-1 in mammalian cells suppresses apoptosis induced by Bax, a pro-apoptotic member of the Bcl-2 family. BI-1 has been shown to be associated with calcium (Ca(2+)) levels, reactive oxygen species (ROS) production, cytosolic acidification, and autophagy as well as endoplasmic reticulum stress signaling pathways. According to both in vitro and clinical studies, BI-1 promotes the characteristics of cancers. In other diseases, BI-1 has also been shown to regulate insulin resistance, adipocyte differentiation, hepatic dysfunction and depression. However, the roles of BI-1 in these disease conditions are not fully consistent among studies. Until now, the molecular mechanisms of BI-1 have not directly explained with regard to how these conditions can be regulated. Therefore, this review investigates the physiological role of BI-1 through molecular mechanism studies and its application in various diseases.
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Affiliation(s)
- Li B
- Department of Pharmacology, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
| | - Yadav R.K
- Department of Pharmacology, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
| | - Jeong G.S
- Department of Pharmacology, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
| | - Kim H.-R
- Department of Dental Pharmacology and Wonkwang Dental Research Institute, School of Dentistry, Wonkwang University, Iksan, 570-749, Republic of Korea
| | - Chae H.-J
- Department of Pharmacology, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
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13
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Saraiva N, Prole DL, Carrara G, Johnson BF, Taylor CW, Parsons M, Smith GL. hGAAP promotes cell adhesion and migration via the stimulation of store-operated Ca2+ entry and calpain 2. ACTA ACUST UNITED AC 2013; 202:699-713. [PMID: 23940116 PMCID: PMC3747308 DOI: 10.1083/jcb.201301016] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Golgi antiapoptotic proteins (GAAPs) are highly conserved Golgi membrane proteins that inhibit apoptosis and promote Ca(2+) release from intracellular stores. Given the role of Ca(2+) in controlling cell adhesion and motility, we hypothesized that human GAAP (hGAAP) might influence these events. In this paper, we present evidence that hGAAP increased cell adhesion, spreading, and migration in a manner that depended on the C-terminal domain of hGAAP. We show that hGAAP increased store-operated Ca(2+) entry and thereby the activity of calpain at newly forming protrusions. These hGAAP-dependent effects regulated focal adhesion dynamics and cell migration. Indeed, inhibition or knockdown of calpain 2 abrogated the effects of hGAAP on cell spreading and migration. Our data reveal that hGAAP is a novel regulator of focal adhesion dynamics, cell adhesion, and migration by controlling localized Ca(2+)-dependent activation of calpain.
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Affiliation(s)
- Nuno Saraiva
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, England, UK
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14
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Kiviluoto S, Luyten T, Schneider L, Lisak D, Rojas-Rivera D, Welkenhuyzen K, Missaen L, De Smedt H, Parys JB, Hetz C, Methner A, Bultynck G. Bax Inhibitor-1-mediated Ca2+ leak is decreased by cytosolic acidosis. Cell Calcium 2013; 54:186-92. [PMID: 23867001 DOI: 10.1016/j.ceca.2013.06.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 05/10/2013] [Accepted: 06/07/2013] [Indexed: 10/26/2022]
Abstract
Bax Inhibitor-1 (BI-1) is an evolutionarily conserved six-transmembrane domain endoplasmic reticulum (ER)-localized protein that protects against ER stress-induced apoptotic cell death. This function is closely connected to its ability to lower steady-state ER Ca2+ levels. Recently, we elucidated BI-1's Ca(2+)-channel pore in the C-terminal part of the protein and identified the critical amino acids of its pore. Based on these insights, a Ca(2+)-channel pore-dead mutant BI-1 (BI-1(D213R)) was developed. We determined whether BI-1 behaves as a bona fide H+/Ca2+ antiporter or as an ER Ca(2+)-leak channel by investigating the effect of pH on unidirectional Ca(2+)-efflux rates. At pH 6.8, wild-type BI-1 expression in BI-1(-/-) cells increased the ER Ca(2+)-leak rate, correlating with its localization in the ER compartment. In contrast, BI-1(D231R) expression in BI-1(-/-), despite its ER localization, did not increase the ER Ca(2+)-leak rate. However, at pH < 6.8, the BI-1-mediated ER Ca2+ leak was blocked. Finally, a peptide representing the Ca(2+)-channel pore of BI-1 promoting Ca2+ flux from the ER was used. Lowering the pH from 6.8 to 6.0 completely abolished the ability of the BI-1 peptide to mediate Ca2+ flux from the ER. We propose that this pH dependence is due to two aspartic acid residues critical for the function of the Ca(2+)-channel pore and located in the ER membrane-dipping domain, which facilitates the protonation of these residues.
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Affiliation(s)
- Santeri Kiviluoto
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg O/N-I, Herestraat 49--box 802, BE-3000 Leuven, Belgium
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15
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Saraiva N, Prole DL, Carrara G, Maluquer de Motes C, Johnson BF, Byrne B, Taylor CW, Smith GL. Human and viral Golgi anti-apoptotic proteins (GAAPs) oligomerize via different mechanisms and monomeric GAAP inhibits apoptosis and modulates calcium. J Biol Chem 2013; 288:13057-67. [PMID: 23508950 PMCID: PMC3642348 DOI: 10.1074/jbc.m112.414367] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Golgi anti-apoptotic proteins (GAAPs) are hydrophobic proteins resident in membranes of the Golgi complex. They protect cells from a range of apoptotic stimuli, reduce the Ca2+ content of intracellular stores, and regulate Ca2+ fluxes. GAAP was discovered in camelpox virus, but it is highly conserved throughout evolution and encoded by all eukaryote genomes examined. GAAPs are part of the transmembrane Bax inhibitor-containing motif (TMBIM) family that also includes other anti-apoptotic and Ca2+-modulating membrane proteins. Most TMBIM members show multiple bands when analyzed by SDS-PAGE, suggesting that they may be oligomeric. However, the molecular mechanisms of oligomerization, the native state of GAAPs in living cells and the functional significance of oligomerization have not been addressed. TMBIM members are thought to have evolved from an ancestral GAAP. Two different GAAPs, human (h) and viral (v)GAAP were therefore selected as models to examine oligomerization of TMBIM family members. We show that both hGAAP and vGAAP in their native states form oligomers and that oligomerization is pH-dependent. Surprisingly, hGAAP and vGAAP do not share the same oligomerization mechanism. Oligomerization of hGAAP is independent of cysteines, but oligomerization of vGAAP depends on cysteines 9 and 60. A mutant vGAAP that is unable to oligomerize revealed that monomeric vGAAP retains both its anti-apoptotic function and its effect on intracellular Ca2+ stores. In conclusion, GAAP can oligomerize in a pH-regulated manner, and monomeric GAAP is functional.
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Affiliation(s)
- Nuno Saraiva
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
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16
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Regulation of inositol 1,4,5-trisphosphate receptors during endoplasmic reticulum stress. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1612-24. [PMID: 23380704 DOI: 10.1016/j.bbamcr.2013.01.026] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 01/13/2013] [Accepted: 01/21/2013] [Indexed: 12/15/2022]
Abstract
The endoplasmic reticulum (ER) performs multiple functions in the cell: it is the major site of protein and lipid synthesis as well as the most important intracellular Ca(2+) reservoir. Adverse conditions, including a decrease in the ER Ca(2+) level or an increase in oxidative stress, impair the formation of new proteins, resulting in ER stress. The subsequent unfolded protein response (UPR) is a cellular attempt to lower the burden on the ER and to restore ER homeostasis by imposing a general arrest in protein synthesis, upregulating chaperone proteins and degrading misfolded proteins. This response can also lead to autophagy and, if the stress can not be alleviated, to apoptosis. The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) and IP3-induced Ca(2+) signaling are important players in these processes. Not only is the IP3R activity modulated in a dual way during ER stress, but also other key proteins involved in Ca(2+) signaling are modulated. Changes also occur at the structural level with a strengthening of the contacts between the ER and the mitochondria, which are important determinants of mitochondrial Ca(2+) uptake. The resulting cytoplasmic and mitochondrial Ca(2+) signals will control cellular decisions that either promote cell survival or cause their elimination via apoptosis. This article is part of a Special Issue entitled: 12th European Symposium on Calcium.
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17
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Li B, Reed JC, Kim HR, Chae HJ. Proteomic profiling of differentially expressed proteins from Bax inhibitor-1 knockout and wild type mice. Mol Cells 2012; 34:15-23. [PMID: 22736268 PMCID: PMC3887783 DOI: 10.1007/s10059-012-0001-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 04/04/2012] [Accepted: 05/12/2012] [Indexed: 02/02/2023] Open
Abstract
Bax inhibitor-1 (BI-1) is an anti-apoptotic protein located in the endoplasmic reticulum (ER). The role of BI-1 has been studied in different physiopathological models including ischemia, diabetes, liver regeneration and cancer. However, fundamental knowledge about the effects of BI-1 deletion on the proteome is lacking. To further explore this protein, we compared the levels of different proteins in bi-1 (-/-) and bi-1 (+/+) mouse tissues by two-dimensional electrophoresis (2-DE) and mass spectrometry (MS). In several bi-1 (-/-) mice, glucose-regulated protein 75 (GRP75/mortalin/ PBP74/mthsp70), peroxiredoxin6 (Prx6) and fumarylacetoacetate hydrolase (FAH) showed a pI shift that could be attributed to post-translational modifications. Selenium-binding protein 2 (SBP2) and ferritin light chain 1 levels were significantly increased. Phosphatidylethanolamine-binding protein-1 (PEBP-1) was dramatically decreased in bi-1 (-/-) mice, which was confirmed by Western blotting. The phosphorylation of GRP75, Prx6 and FAH were compared between bi-1 (+/+) and bi-1 (-/-) mice using liver tissue lysates. Of these three proteins, only one exhibited modified phosphorylation; Tyr phosphorylation of Prx6 was increased in bi-1 (-/-) mice. Our protein profiling results provide fundamental knowledge about the physiopathological function of BI-1.
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Affiliation(s)
- Bo Li
- Department of Pharmacology and Cardiovascular Research Center, Chonbuk National University, Jeonju 561-182,
Korea
| | - John C. Reed
- Burnham Institute for Medical Research, California 92037,
USA
| | - Hyung-Ryong Kim
- Department of Dental Pharmacology, School of Dentistry, Wonkwang University, Iksan 570-749,
Korea
| | - Han-Jung Chae
- Department of Pharmacology and Cardiovascular Research Center, Chonbuk National University, Jeonju 561-182,
Korea
- Research Center for Pulmonary Disorders, Chonbuk National University Hospital, Jeonju 561-182,
Korea
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18
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Carrara G, Saraiva N, Gubser C, Johnson BF, Smith GL. Six-transmembrane topology for Golgi anti-apoptotic protein (GAAP) and Bax inhibitor 1 (BI-1) provides model for the transmembrane Bax inhibitor-containing motif (TMBIM) family. J Biol Chem 2012; 287:15896-905. [PMID: 22418439 PMCID: PMC3346125 DOI: 10.1074/jbc.m111.336149] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Golgi anti-apoptotic protein (GAAP) is a hydrophobic Golgi protein that regulates intracellular calcium fluxes and apoptosis. GAAP is highly conserved throughout eukaryotes and some strains of vaccinia virus (VACV) and camelpox virus. Based on sequence, phylogeny, and hydrophobicity, GAAPs were classified within the transmembrane Bax inhibitor-containing motif (TMBIM) family. TMBIM members are anti-apoptotic and were predicted to have seven-transmembrane domains (TMDs). However, topology prediction programs are inconsistent and predicted that GAAP and other TMBIM members have six or seven TMDs. To address this discrepancy, we mapped the transmembrane topology of viral (vGAAP) and human (hGAAP), as well as Bax inhibitor (BI-1). Data presented show a six-, not seven-, transmembrane topology for vGAAP with a putative reentrant loop at the C terminus and both termini located in the cytosol. We find that this topology is also conserved in hGAAP and BI-1. This places the charged C terminus in the cytosol, and mutation of these charged residues in hGAAP ablated its anti-apoptotic function. Given the highly conserved hydrophobicity profile within the TMBIM family and recent phylogenetic data indicating that a GAAP-like protein may have been the ancestral progenitor of a subset of the TMBIM family, we propose that this vGAAP topology may be used as a model for the remainder of the TMBIM family of proteins. The topology described provides valuable information on the structure and function of an important but poorly understood family of proteins.
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Affiliation(s)
- Guia Carrara
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom
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19
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Yun CH, Chae HJ, Kim HR, Ahn T. Doxorubicin- and daunorubicin-induced regulation of Ca2+ and H+ fluxes through human bax inhibitor-1 reconstituted into membranes. J Pharm Sci 2011; 101:1314-26. [PMID: 22147501 DOI: 10.1002/jps.23007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 09/28/2011] [Accepted: 11/15/2011] [Indexed: 11/05/2022]
Abstract
Bax inhibitor-1 (BI-1) is an evolutionarily conserved cell death suppressor in both animals and plants. We examined the effect of doxorubicin (DXR) and daunorubicin (DNR), which are clinically important anthracycline compounds, on the functional regulation of BI-1 reconstituted into membranes. DXR and DNR inhibited the proton-induced efflux of encapsulated Ca(2+) from membranes in a drug concentration-dependent manner. Both compounds also reduced the H(+) influx activity of BI-1. The proteoliposomes containing BI-1 increased the quenching of DXR fluorescence by Cu(2+), and the fluorescence energy transfer between pyrene-labeled BI-1 and DXR was enhanced with increasing DXR concentrations. The dissociation constants and the number of binding sites for both drugs in BI-1 were determined to be in the range of 3.7-4.5 × 10(-6) m and approximately 4-5/BI-1 molecule, respectively, using a proteomicelle system. DXR also induced secondary structural changes in reconstituted BI-1 and abolished the ability of BI-1-overexpressing cells to protect against endoplasmic reticulum stress-induced cell death. However, when mitoxantrone was used instead of DNR and DXR as an anthracycline analog, no significant effects were observed. These results suggest that BI-1 can be considered to be a new cancer therapeutic target by anthracyclines because of its stimulatory effects in cancer/tumor progression.
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Affiliation(s)
- Chul-ho Yun
- School of Biological Sciences and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea
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20
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Bultynck G, Kiviluoto S, Henke N, Ivanova H, Schneider L, Rybalchenko V, Luyten T, Nuyts K, De Borggraeve W, Bezprozvanny I, Parys JB, De Smedt H, Missiaen L, Methner A. The C terminus of Bax inhibitor-1 forms a Ca2+-permeable channel pore. J Biol Chem 2011; 287:2544-57. [PMID: 22128171 DOI: 10.1074/jbc.m111.275354] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Bax inhibitor-1 (BI-1) is a multitransmembrane domain-spanning endoplasmic reticulum (ER)-located protein that is evolutionarily conserved and protects against apoptosis and ER stress. Furthermore, BI-1 is proposed to modulate ER Ca(2+) homeostasis by acting as a Ca(2+)-leak channel. Based on experimental determination of the BI-1 topology, we propose that its C terminus forms a Ca(2+) pore responsible for its Ca(2+)-leak properties. We utilized a set of C-terminal peptides to screen for Ca(2+) leak activity in unidirectional (45)Ca(2+)-flux experiments and identified an α-helical 20-amino acid peptide causing Ca(2+) leak from the ER. The Ca(2+) leak was independent of endogenous ER Ca(2+)-release channels or other Ca(2+)-leak mechanisms, namely translocons and presenilins. The Ca(2+)-permeating property of the peptide was confirmed in lipid-bilayer experiments. Using mutant peptides, we identified critical residues responsible for the Ca(2+)-leak properties of this BI-1 peptide, including a series of critical negatively charged aspartate residues. Using peptides corresponding to the equivalent BI-1 domain from various organisms, we found that the Ca(2+)-leak properties were conserved among animal, but not plant and yeast orthologs. By mutating one of the critical aspartate residues in the proposed Ca(2+)-channel pore in full-length BI-1, we found that Asp-213 was essential for BI-1-dependent ER Ca(2+) leak. Thus, we elucidated residues critically important for BI-1-mediated Ca(2+) leak and its potential channel pore. Remarkably, one of these residues was not conserved among plant and yeast BI-1 orthologs, indicating that the ER Ca(2+)-leak properties of BI-1 are an added function during evolution.
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Affiliation(s)
- Geert Bultynck
- Department of Molecular Cell Biology, Laboratory of Molecular and Cellular Signaling, K.U. Leuven, B-3000 Leuven, Belgium.
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21
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Lee GH, Hwang JD, Choi JY, Park HJ, Cho JY, Kim KW, Chae HJ, Kim HR. An acidic pH environment increases cell death and pro-inflammatory cytokine release in osteoblasts: The involvement of BAX Inhibitor-1. Int J Biochem Cell Biol 2011; 43:1305-17. [DOI: 10.1016/j.biocel.2011.05.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 04/08/2011] [Accepted: 05/04/2011] [Indexed: 12/29/2022]
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22
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Henke N, Lisak DA, Schneider L, Habicht J, Pergande M, Methner A. The ancient cell death suppressor BAX inhibitor-1. Cell Calcium 2011; 50:251-60. [PMID: 21663964 DOI: 10.1016/j.ceca.2011.05.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Revised: 05/03/2011] [Accepted: 05/05/2011] [Indexed: 10/18/2022]
Abstract
Bax inhibitor-1 (BI-1) was initially identified for its ability to inhibit BAX-induced apoptosis in yeast cells and is the founding member of a family of highly hydrophobic proteins localized in diverse cellular membranes. It is evolutionarily conserved and orthologues from plants can substitute for mammalian BI-1 in regard to its anti-apoptotic function suggesting a high degree of functional conservation. BI-1 interacts with BCL-2 and BCL-XL and, similar to these two anti-apoptotic proteins, the effect of BI-1 on cell death involves changes in the amount of Ca(2+) releasable from intracellular stores. However, BI-1 is also a negative regulator of the endoplasmic reticulum stress sensor IRE1 α, it interacts with G-actin and increases actin polymerization, enhances cancer metastasis by altering glucose metabolism and activating the sodium-hydrogen exchanger, and reduces the production of reactive oxygen species through direct interaction with NADPH-P450 reductase. In this contribution, we summarize what is known about the expression, intracellular localization and structure of BI-1 and specifically illuminate its effects on the intracellular Ca(2+) homeostasis and how this might relate to its other functions. We also present a thorough phylogenetic analysis of BI-1 proteins from major phyla together with paralogues from all BI-1 family members.
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Affiliation(s)
- Nadine Henke
- Neurologische Klinik, Universitätsklinikum Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
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23
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Cebulski J, Malouin J, Pinches N, Cascio V, Austriaco N. Yeast Bax inhibitor, Bxi1p, is an ER-localized protein that links the unfolded protein response and programmed cell death in Saccharomyces cerevisiae. PLoS One 2011; 6:e20882. [PMID: 21673967 PMCID: PMC3108976 DOI: 10.1371/journal.pone.0020882] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 05/11/2011] [Indexed: 12/27/2022] Open
Abstract
Bax inhibitor-1 (BI-1) is an anti-apoptotic gene whose expression is upregulated in a wide range of human cancers. Studies in both mammalian and plant cells suggest that the BI-1 protein resides in the endoplasmic reticulum and is involved in the unfolded protein response (UPR) that is triggered by ER stress. It is thought to act via a mechanism involving altered calcium dynamics. In this paper, we provide evidence that the Saccharomyces cerevisiae protein encoded by the open reading frame, YNL305C, is a bona fide homolog for BI-1. First, we confirm that yeast cells from two different strain backgrounds lacking YNL305C, which we have renamed BXI1, are more sensitive to heat-shock induced cell death than wildtype controls even though they have indistinguishable growth rates at 30°C. They are also more susceptible both to ethanol-induced and to glucose-induced programmed cell death. Significantly, we show that Bxi1p-GFP colocalizes with the ER localized protein Sec63p-RFP. We have also discovered that Δbxi1 cells are not only more sensitive to drugs that induce ER stress, but also have a decreased unfolded protein response as measured with a UPRE-lacZ reporter. Finally, we have discovered that deleting BXI1 diminishes the calcium signaling response in response to the accumulation of unfolded proteins in the ER as measured by a calcineurin-dependent CDRE-lacZ reporter. In toto, our data suggests that the Bxi1p, like its metazoan homologs, is an ER-localized protein that links the unfolded protein response and programmed cell death.
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Affiliation(s)
- James Cebulski
- Department of Biology, Providence College, Providence, Rhode Island, United States of America
| | - Joshua Malouin
- Department of Biology, Providence College, Providence, Rhode Island, United States of America
| | - Nathan Pinches
- Department of Biology, Providence College, Providence, Rhode Island, United States of America
| | - Vincent Cascio
- Department of Biology, Providence College, Providence, Rhode Island, United States of America
| | - Nicanor Austriaco
- Department of Biology, Providence College, Providence, Rhode Island, United States of America
- * E-mail:
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24
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Ishikawa T, Watanabe N, Nagano M, Kawai-Yamada M, Lam E. Bax inhibitor-1: a highly conserved endoplasmic reticulum-resident cell death suppressor. Cell Death Differ 2011; 18:1271-8. [PMID: 21597463 DOI: 10.1038/cdd.2011.59] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In spite of fundamental differences between plant and animal cells, it is remarkable that some cell death regulators that were identified to control cell death in metazoans can also function in plants. The fact that most of these proteins do not have structural homologs in plant genomes suggests that they may be targeting a highly conserved 'core' mechanism with conserved functions that is present in all eukaryotes. The ubiquitous Bax inhibitor-1 (BI-1) is a common cell death suppressor in eukaryotes that has provided a potential portal to this cell death core. In this review, we will update the current status of our understanding on the function and activities of this intriguing protein. Genetic, molecular and biochemical studies have so far suggested a consistent view that BI-1 is an endoplasmic reticulum (ER)-resident transmembrane protein that can interact with multiple partners to alter intracellular Ca(2+) flux control and lipid dynamics. Functionally, the level of BI-1 protein has been hypothesized to have the role of a rheostat to regulate the threshold of ER-stress inducible cell death. Further, delineation of the cell death suppression mechanism by BI-1 should shed light on an ancient cell death core-control pathway in eukaryotes, as well as novel ways to improve stress tolerance.
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Affiliation(s)
- T Ishikawa
- Department of Environmental Science and Technology, Saitama University, Saitama 338-8570, Japan
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25
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Robinson KS, Clements A, Williams AC, Berger CN, Frankel G. Bax Inhibitor 1 in apoptosis and disease. Oncogene 2011; 30:2391-400. [DOI: 10.1038/onc.2010.636] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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26
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Ahn T, Yun CH, Kim HR, Chae HJ. Cardiolipin, phosphatidylserine, and BH4 domain of Bcl-2 family regulate Ca2+/H+ antiporter activity of human Bax inhibitor-1. Cell Calcium 2010; 47:387-96. [PMID: 20193962 DOI: 10.1016/j.ceca.2010.02.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 02/05/2010] [Accepted: 02/05/2010] [Indexed: 11/30/2022]
Abstract
We investigated the effects of phospholipid composition in membranes and Bcl-2 homology (BH) domains of the Bcl-2 family on Ca2+/H+ antiporter activity of human recombinant Bax inhibitor-1 (BI-1) reconstituted into membranes. Cardiolipin (CL) and phosphatidylserine (PS) stimulated the proton-mediated efflux of Ca2+ ions encapsulated into proteoliposomes when compared to Ca2+ efflux from 100% phosphatidylcholine (PC) membranes in a CL or PS concentration-dependent manner. Concomitantly, the anionic phospholipids also enhanced H+ ion influx into the membranes. Lateral segregations of CL and PS were observed through the fluorescence properties of fluorophore-labeled phospholipids upon BI-1 reconstitution in PC/CL or PC/PS binary systems. However, other anionic phospholipids, such as phosphatidic acid, phosphatidylglycerol, and phosphatidylinositol did not influence the stimulation of BI-1 functions in membranes. The peptide corresponding to the BH4 domain of Bcl-2 and Bcl-xL proteins stimulated the BI-1 activities in 100% PC membranes. The peptide also showed an additive effect with CL or PS. Furthermore, the CL, PS, and BH4 domains specifically increased oligomerization levels such as dimer and tetramer of BI-1 in membranes. Taken together, these results suggest that the CL, PS, and BH4 domains were stimulating factors for the Ca2+/H+ antiporter activities of BI-1 through protein oligomerization.
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Affiliation(s)
- Taeho Ahn
- Department of Biochemistry, College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, Republic of Korea.
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27
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Bax Inhibitor-1, a conserved cell death suppressor, is a key molecular switch downstream from a variety of biotic and abiotic stress signals in plants. Int J Mol Sci 2009; 10:3149-3167. [PMID: 19742129 PMCID: PMC2738916 DOI: 10.3390/ijms10073149] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 07/06/2009] [Accepted: 07/06/2009] [Indexed: 02/03/2023] Open
Abstract
In Nature plants are constantly challenged by a variety of environmental stresses that could lead to disruptions in cellular homeostasis. Programmed cell death (PCD) is a fundamental cellular process that is often associated with defense responses to pathogens, during development and in response to abiotic stresses in fungi, animals and plants. Although there are many characteristics shared between different types of PCD events, it remains unknown whether a common mechanism drives various types of PCD in eukaryotes. One candidate regulator for such a mechanism is Bax Inhibitor-1 (BI-1), an evolutionary conserved, endoplasmic reticulum (ER)-resident protein that represents an ancient cell death regulator that potentially regulates PCD in all eukaryotes. Recent findings strongly suggested that BI-1 plays an important role in the conserved ER stress response pathway to modulate cell death induction in response to multiple types of cell death signals. As ER stress signaling pathways has been suggested to play important roles not only in the control of ER homeostasis but also in other biological processes such as the response to pathogens and abiotic stress in plants, BI-1 might function to control the convergence point that modulates the level of the “pro-survival and pro-death” signals under multiple stress conditions.
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Chapter 7 Influenza A M2. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/s1554-4516(09)10007-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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