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Teardo E, Carraretto L, Wagner S, Formentin E, Behera S, De Bortoli S, Larosa V, Fuchs P, Lo Schiavo F, Raffaello A, Rizzuto R, Costa A, Schwarzländer M, Szabò I. Physiological Characterization of a Plant Mitochondrial Calcium Uniporter in Vitro and in Vivo. PLANT PHYSIOLOGY 2017; 173:1355-1370. [PMID: 28031475 PMCID: PMC5291028 DOI: 10.1104/pp.16.01359] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/21/2016] [Indexed: 05/19/2023]
Abstract
Over the recent years, several proteins that make up the mitochondrial calcium uniporter complex (MCUC) mediating Ca2+uptake into the mitochondrial matrix have been identified in mammals, including the channel-forming protein MCU. Although six MCU gene homologs are conserved in the model plant Arabidopsis (Arabidopsis thaliana) in which mitochondria can accumulate Ca2+, a functional characterization of plant MCU homologs has been lacking. Using electrophysiology, we show that one isoform, AtMCU1, gives rise to a Ca2+-permeable channel activity that can be observed even in the absence of accessory proteins implicated in the formation of the active mammalian channel. Furthermore, we provide direct evidence that AtMCU1 activity is sensitive to the mitochondrial calcium uniporter inhibitors Ruthenium Red and Gd3+, as well as to the Arabidopsis protein MICU, a regulatory MCUC component. AtMCU1 is prevalently expressed in roots, localizes to mitochondria, and its absence causes mild changes in Ca2+ dynamics as assessed by in vivo measurements in Arabidopsis root tips. Plants either lacking or overexpressing AtMCU1 display root mitochondria with altered ultrastructure and show shorter primary roots under restrictive growth conditions. In summary, our work adds evolutionary depth to the investigation of mitochondrial Ca2+ transport, indicates that AtMCU1, together with MICU as a regulator, represents a functional configuration of the plant mitochondrial Ca2+ uptake complex with differences to the mammalian MCUC, and identifies a new player of the intracellular Ca2+ regulation network in plants.
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Affiliation(s)
- Enrico Teardo
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy;
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.);
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.);
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Luca Carraretto
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Stephan Wagner
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Elide Formentin
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Smrutisanjita Behera
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Sara De Bortoli
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Véronique Larosa
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Philippe Fuchs
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Fiorella Lo Schiavo
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Anna Raffaello
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Rosario Rizzuto
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Alex Costa
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Markus Schwarzländer
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.)
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.)
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
| | - Ildiko Szabò
- Department of Biology (E.T., L.C., E.F., S.D.B., V.L., F.L.S., I.S.) and Department of Biomedical Sciences (A.R., R.R.), University of Padova, 35121 Padova, Italy;
- CNR Institute of Neuroscience, Padova, Italy, Department of Biomedical Sciences, University of Padua, 35121 Padova, Italy (E.T., I.S.);
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany (S.W., P.F., M.S.);
- Department of Biosciences, University of Milan, 20133 Milan, Italy (S.B., A.C.); and
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy (A.C.)
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102
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Kwong JQ. The mitochondrial calcium uniporter in the heart: energetics and beyond. J Physiol 2017; 595:3743-3751. [PMID: 27991671 DOI: 10.1113/jp273059] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 11/21/2016] [Indexed: 01/11/2023] Open
Abstract
Ca2+ and mitochondria are inextricably linked to cardiac function and dysfunction. Ca2+ is central to cardiac excitation-contraction coupling and stimulates mitochondrial energy production to fuel contraction. Under pathological conditions of dysregulated Ca2+ cycling, mitochondrial Ca2+ overload activates cellular death pathways. Thus, in the cardiomyocyte, the mitochondrial Ca2+ microdomain is where contraction, energy and death collide. A key component of mitochondrial Ca2+ signalling is the mitochondrial Ca2+ uniporter complex (uniplex), an inner membrane Ca2+ transporter and major pathway of mitochondrial Ca2+ entry. Once known only as the unidentified target for ruthenium red and related compounds, in recent years, the uniplex has evolved into a complex multiprotein assembly. The identification of the molecular constituents of the uniplex has made possible the generation of targeted genetic models to interrogate uniplex function in vivo. This review will summarize our current understanding of the molecular structure of the uniplex, its impact on mitochondrial energetics and cardiac physiology, its contribution to cardiomyocyte death, and its expanding roles in cardiac biology.
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Affiliation(s)
- Jennifer Q Kwong
- Department of Pediatrics, Division of Cardiovascular Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
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103
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Bhosale G, Sharpe JA, Koh A, Kouli A, Szabadkai G, Duchen MR. Pathological consequences of MICU1 mutations on mitochondrial calcium signalling and bioenergetics. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1009-1017. [PMID: 28132899 PMCID: PMC5424885 DOI: 10.1016/j.bbamcr.2017.01.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/20/2017] [Accepted: 01/21/2017] [Indexed: 01/07/2023]
Abstract
Loss of function mutations of the protein MICU1, a regulator of mitochondrial Ca2 + uptake, cause a neuronal and muscular disorder characterised by impaired cognition, muscle weakness and an extrapyramidal motor disorder. We have shown previously that MICU1 mutations cause increased resting mitochondrial Ca2+ concentration ([Ca2 +]m). We now explore the functional consequences of MICU1 mutations in patient derived fibroblasts in order to clarify the underlying pathophysiology of this disorder. We propose that deregulation of mitochondrial Ca2+ uptake through loss of MICU1 raises resting [Ca2+]m, initiating a futile Ca2+ cycle, whereby continuous mitochondrial Ca2+ influx is balanced by Ca2+ efflux through the sodium calcium exchanger (NLCXm). Thus, inhibition of NCLXm by CGP-37157 caused rapid mitochondrial Ca2+ accumulation in patient but not control cells. We suggest that increased NCLX activity will increase sodium/proton exchange, potentially undermining oxidative phosphorylation, although this is balanced by dephosphorylation and activation of pyruvate dehydrogenase (PDH) in response to the increased [Ca2+]m. Consistent with this model, while ATP content in patient derived or control fibroblasts was not different, ATP increased significantly in response to CGP-37157 in the patient but not the control cells. In addition, EMRE expression levels were altered in MICU1 patient cells compared to the controls. The MICU1 mutations were associated with mitochondrial fragmentation which we show is related to altered DRP1 phosphorylation. Thus, MICU1 serves as a signal–noise discriminator in mitochondrial calcium signalling, limiting the energetic costs of mitochondrial Ca2+ signalling which may undermine oxidative phosphorylation, especially in tissues with highly dynamic energetic demands. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech. Loss of MICU1 protein expression in human fibroblasts increases resting mitochondrial calcium concentration ([Ca2+]m). The increased mitochondrial Ca2+ uptake causes a futile Ca2+ cycle in MICU1 deficient cells. Increased [Ca2+]mactivates pyruvate dehydrogenase (PDH) by activating PDH phosphatase, consequently dephosphorylating PDH. Loss of MICU1 leads to modifications of the MCU complex composition and mitochondrial fragmentation.
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Affiliation(s)
- Gauri Bhosale
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Jenny A Sharpe
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Amanda Koh
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Antonina Kouli
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Gyorgy Szabadkai
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom; Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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104
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Gao Y, Hou R, Fei Q, Fang L, Han Y, Cai R, Peng C, Qi Y. The Three-Herb Formula Shuang-Huang-Lian stabilizes mast cells through activation of mitochondrial calcium uniporter. Sci Rep 2017; 7:38736. [PMID: 28045016 PMCID: PMC5206722 DOI: 10.1038/srep38736] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 11/14/2016] [Indexed: 12/31/2022] Open
Abstract
Mast cells (MCs) are key effector cells of IgE-FcεRI- or MrgprX2-mediated signaling event. Shuang-Huang-Lian (SHL), a herbal formula from Chinese Pharmacopoeia, has been clinically used in type I hypersensitivity. Our previous study demonstrated that SHL exerted a non-negligible effect on MC stabilization. Herein, we sought to elucidate the molecular mechanisms of the prominent anti-allergic ability of SHL. MrgprX2- and IgE-FcεRI-mediated MC activation in vitro and in vivo models were developed by using compound 48/80 (C48/80) and shrimp tropomyosin (ST), respectively. Our data showed that SHL markedly dampened C48/80- or ST-induced MC degranulation in vitro and in vivo. Mechanistic study indicated that cytosolic Ca2+ (Ca2+[c]) level decreased rapidly and sustainably after SHL treatment, and then returned to homeostasis when SHL was withdrawn. Moreover, SHL decreases Ca2+[c] levels mainly through enhancing the mitochondrial Ca2+ (Ca2+[m]) uptake. After genetically silencing or pharmacologic inhibiting mitochondrial calcium uniporter (MCU), the effect of SHL on the Ca2+[c] level and MC degranulation was significantly weakened. Simultaneously, the activation of SHL on Ca2+[m] uptake was completely lost. Collectively, by activating MCU, SHL decreases Ca2+[c] level to stabilize MCs, thus exerting a remarkable anti-allergic activity, which could have considerable influences on clinical practice and research.
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Affiliation(s)
- Yuan Gao
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences &Peking Union Medical College, Beijing, 100193, China.,Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Rui Hou
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences &Peking Union Medical College, Beijing, 100193, China
| | - Qiaoling Fei
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences &Peking Union Medical College, Beijing, 100193, China
| | - Lei Fang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences &Peking Union Medical College, Beijing, 100193, China
| | - Yixin Han
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences &Peking Union Medical College, Beijing, 100193, China
| | - Runlan Cai
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences &Peking Union Medical College, Beijing, 100193, China
| | - Cheng Peng
- Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Yun Qi
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences &Peking Union Medical College, Beijing, 100193, China
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105
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Mishra J, Jhun BS, Hurst S, O-Uchi J, Csordás G, Sheu SS. The Mitochondrial Ca 2+ Uniporter: Structure, Function, and Pharmacology. Handb Exp Pharmacol 2017; 240:129-156. [PMID: 28194521 PMCID: PMC5554456 DOI: 10.1007/164_2017_1] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Mitochondrial Ca2+ uptake is crucial for an array of cellular functions while an imbalance can elicit cell death. In this chapter, we briefly reviewed the various modes of mitochondrial Ca2+ uptake and our current understanding of mitochondrial Ca2+ homeostasis in regards to cell physiology and pathophysiology. Further, this chapter focuses on the molecular identities, intracellular regulators as well as the pharmacology of mitochondrial Ca2+ uniporter complex.
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Affiliation(s)
- Jyotsna Mishra
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, 1020 Locust Street, Suite 543D, Philadelphia, PA, 19107, USA
| | - Bong Sook Jhun
- Cardiovascular Research Center, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, 02903, USA
| | - Stephen Hurst
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, 1020 Locust Street, Suite 543D, Philadelphia, PA, 19107, USA
| | - Jin O-Uchi
- Cardiovascular Research Center, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI, 02903, USA.
| | - György Csordás
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA.
| | - Shey-Shing Sheu
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, 1020 Locust Street, Suite 543D, Philadelphia, PA, 19107, USA.
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106
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Spät A, Szanda G. The Role of Mitochondria in the Activation/Maintenance of SOCE: Store-Operated Ca 2+ Entry and Mitochondria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:257-275. [PMID: 28900919 DOI: 10.1007/978-3-319-57732-6_14] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mitochondria extensively modify virtually all cellular Ca2+ transport processes, and store-operated Ca2+ entry (SOCE) is no exception to this rule. The interaction between SOCE and mitochondria is complex and reciprocal, substantially altering and, ultimately, fine-tuning both capacitative Ca2+ influx and mitochondrial function. Mitochondria, owing to their considerable Ca2+ accumulation ability, extensively buffer the cytosolic Ca2+ in their vicinity. In turn, the accumulated ion is released back into the neighboring cytosol during net Ca2+ efflux. Since store depletion itself and the successive SOCE are both Ca2+-regulated phenomena, mitochondrial Ca2+ handling may have wide-ranging effects on capacitative Ca2+ influx at any given time. In addition, mitochondria may also produce or consume soluble factors known to affect store-operated channels. On the other hand, Ca2+ entering the cell during SOCE is sensed by mitochondria, and the ensuing mitochondrial Ca2+ uptake boosts mitochondrial energy metabolism and, if Ca2+ overload occurs, may even lead to apoptosis or cell death. In several cell types, mitochondria seem to be sterically excluded from the confined space that forms between the plasma membrane (PM) and endoplasmic reticulum (ER) during SOCE. This implies that high-Ca2+ microdomains comparable to those observed between the ER and mitochondria do not form here. In the following chapter, the above aspects of the many-sided SOCE-mitochondrion interplay will be discussed in greater detail.
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Affiliation(s)
- András Spät
- Department of Physiology, Semmelweis University Medical School, POB 2, 1428, Budapest, Hungary.
- Laboratory of Molecular Physiology, Hungarian Academy of Sciences, Budapest, Hungary.
| | - Gergö Szanda
- Department of Physiology, Semmelweis University Medical School, POB 2, 1428, Budapest, Hungary
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107
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Mitochondrial Calcium Handling in Physiology and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 982:25-47. [PMID: 28551780 DOI: 10.1007/978-3-319-55330-6_2] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Calcium (Ca2+) accumulation inside mitochondria represents a pleiotropic signal controlling a wide range of cellular functions, including key metabolic pathways and life/death decisions. This phenomenon has been first described in the 1960s, but the identity of the molecules controlling this process remained a mystery until just few years ago, when both mitochondrial Ca2+ uptake and release systems were genetically dissected. This finally opened the possibility to develop genetic models to directly test the contribution of mitochondrial Ca2+ homeostasis to cellular functions. Here we summarize our current understanding of the molecular machinery that controls mitochondrial Ca2+ handling and critically evaluate the physiopathological role of mitochondrial Ca2+ signaling, based on recent evidences obtained through in vitro and in vivo models.
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108
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Nita II, Caspi Y, Gudes S, Fishman D, Lev S, Hersfinkel M, Sekler I, Binshtok AM. Privileged crosstalk between TRPV1 channels and mitochondrial calcium shuttling machinery controls nociception. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2868-2880. [DOI: 10.1016/j.bbamcr.2016.09.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/06/2016] [Accepted: 09/09/2016] [Indexed: 10/21/2022]
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109
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Bernardi P, Forte M. Commentary: The m-AAA Protease Associated with Neurodegeneration Limits MCU Activity in Mitochondria. Front Physiol 2016; 7:583. [PMID: 27933001 PMCID: PMC5123201 DOI: 10.3389/fphys.2016.00583] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 11/14/2016] [Indexed: 11/21/2022] Open
Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences, University of Padova Padova, Italy
| | - Michael Forte
- Vollum Institute, Oregon Health and Science University Portland, OR, USA
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110
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De La Fuente S, Fernandez-Sanz C, Vail C, Agra EJ, Holmstrom K, Sun J, Mishra J, Williams D, Finkel T, Murphy E, Joseph SK, Sheu SS, Csordás G. Strategic Positioning and Biased Activity of the Mitochondrial Calcium Uniporter in Cardiac Muscle. J Biol Chem 2016; 291:23343-23362. [PMID: 27637331 PMCID: PMC5087749 DOI: 10.1074/jbc.m116.755496] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Indexed: 11/06/2022] Open
Abstract
Control of myocardial energetics by Ca2+ signal propagation to the mitochondrial matrix includes local Ca2+ delivery from sarcoplasmic reticulum (SR) ryanodine receptors (RyR2) to the inner mitochondrial membrane (IMM) Ca2+ uniporter (mtCU). mtCU activity in cardiac mitochondria is relatively low, whereas the IMM surface is large, due to extensive cristae folding. Hence, stochastically distributed mtCU may not suffice to support local Ca2+ transfer. We hypothesized that mtCU concentrated at mitochondria-SR associations would promote the effective Ca2+ transfer. mtCU distribution was determined by tracking MCU and EMRE, the proteins essential for channel formation. Both proteins were enriched in the IMM-outer mitochondrial membrane (OMM) contact point submitochondrial fraction and, as super-resolution microscopy revealed, located more to the mitochondrial periphery (inner boundary membrane) than inside the cristae, indicating high accessibility to cytosol-derived Ca2+ inputs. Furthermore, MCU immunofluorescence distribution was biased toward the mitochondria-SR interface (RyR2), and this bias was promoted by Ca2+ signaling activity in intact cardiomyocytes. The SR fraction of heart homogenate contains mitochondria with extensive SR associations, and these mitochondria are highly enriched in EMRE. Size exclusion chromatography suggested for EMRE- and MCU-containing complexes a wide size range and also revealed MCU-containing complexes devoid of EMRE (thus disabled) in the mitochondrial but not the SR fraction. Functional measurements suggested more effective mtCU-mediated Ca2+ uptake activity by the mitochondria of the SR than of the mitochondrial fraction. Thus, mtCU "hot spots" can be formed at the cardiac muscle mitochondria-SR associations via localization and assembly bias, serving local Ca2+ signaling and the excitation-energetics coupling.
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Affiliation(s)
- Sergio De La Fuente
- From the MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Celia Fernandez-Sanz
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Caitlin Vail
- From the MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Elorm J Agra
- From the MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Kira Holmstrom
- the Center for Molecular Medicine, Laboratory of Molecular Biology, and
| | - Junhui Sun
- the Systems Biology Center, Laboratory of Cardiac Physiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Jyotsna Mishra
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - Dewight Williams
- the Penn EM Resource Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Toren Finkel
- the Center for Molecular Medicine, Laboratory of Molecular Biology, and
| | - Elizabeth Murphy
- the Systems Biology Center, Laboratory of Cardiac Physiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Suresh K Joseph
- From the MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Shey-Shing Sheu
- the Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, and
| | - György Csordás
- From the MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107,
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111
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Raffaello A, Mammucari C, Gherardi G, Rizzuto R. Calcium at the Center of Cell Signaling: Interplay between Endoplasmic Reticulum, Mitochondria, and Lysosomes. Trends Biochem Sci 2016; 41:1035-1049. [PMID: 27692849 DOI: 10.1016/j.tibs.2016.09.001] [Citation(s) in RCA: 356] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/31/2016] [Accepted: 09/07/2016] [Indexed: 12/29/2022]
Abstract
In recent years, rapid discoveries have been made relating to Ca2+ handling at specific organelles that have important implications for whole-cell Ca2+ homeostasis. In particular, the structures of the endoplasmic reticulum (ER) Ca2+ channels revealed by electron cryomicroscopy (cryo-EM), continuous updates on the structure, regulation, and role of the mitochondrial calcium uniporter (MCU) complex, and the analysis of lysosomal Ca2+ signaling are milestones on the route towards a deeper comprehension of the complexity of global Ca2+ signaling. In this review we summarize recent discoveries on the regulation of interorganellar Ca2+ homeostasis and its role in pathophysiology.
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Affiliation(s)
- Anna Raffaello
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.
| | - Cristina Mammucari
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.
| | - Gaia Gherardi
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; Neuroscience Institute, National Research Council, 35131 Padua, Italy.
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112
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Madreiter-Sokolowski CT, Klec C, Parichatikanond W, Stryeck S, Gottschalk B, Pulido S, Rost R, Eroglu E, Hofmann NA, Bondarenko AI, Madl T, Waldeck-Weiermair M, Malli R, Graier WF. PRMT1-mediated methylation of MICU1 determines the UCP2/3 dependency of mitochondrial Ca(2+) uptake in immortalized cells. Nat Commun 2016; 7:12897. [PMID: 27642082 PMCID: PMC5031806 DOI: 10.1038/ncomms12897] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 08/12/2016] [Indexed: 12/18/2022] Open
Abstract
Recent studies revealed that mitochondrial Ca2+ channels, which control energy flow, cell signalling and death, are macromolecular complexes that basically consist of the pore-forming mitochondrial Ca2+ uniporter (MCU) protein, the essential MCU regulator (EMRE), and the mitochondrial Ca2+ uptake 1 (MICU1). MICU1 is a regulatory subunit that shields mitochondria from Ca2+ overload. Before the identification of these core elements, the novel uncoupling proteins 2 and 3 (UCP2/3) have been shown to be fundamental for mitochondrial Ca2+ uptake. Here we clarify the molecular mechanism that determines the UCP2/3 dependency of mitochondrial Ca2+ uptake. Our data demonstrate that mitochondrial Ca2+ uptake is controlled by protein arginine methyl transferase 1 (PRMT1) that asymmetrically methylates MICU1, resulting in decreased Ca2+ sensitivity. UCP2/3 normalize Ca2+ sensitivity of methylated MICU1 and, thus, re-establish mitochondrial Ca2+ uptake activity. These data provide novel insights in the complex regulation of the mitochondrial Ca2+ uniporter by PRMT1 and UCP2/3. MICU1 is a regulatory subunit of mitochondrial Ca2+ channels that shields mitochondria from Ca2+ overload. Here the authors show that MICU1 methylation by PRMT1 reduces Ca2+ sensitivity, which is normalized by UCP2/3, re-establishing mitochondrial Ca2+ uptake activity.
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Affiliation(s)
- Corina T Madreiter-Sokolowski
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Christiane Klec
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Warisara Parichatikanond
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Sarah Stryeck
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Benjamin Gottschalk
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Sergio Pulido
- Institute of Chemistry, University of Graz, Graz 8010, Austria
| | - Rene Rost
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Emrah Eroglu
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Nicole A Hofmann
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Alexander I Bondarenko
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Tobias Madl
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria.,Center for Integrated Protein Science, Department Chemistry, Technical University Munich, Garching 85748, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg 85764, Germany
| | - Markus Waldeck-Weiermair
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Roland Malli
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
| | - Wolfgang F Graier
- Center for Molecular Medicine, Institute of Molecular Biology and Biochemistry, Medical University of Graz, Harrachgasse 21/III, Graz 8010, Austria
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113
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Abstract
Ca
2+ oscillations, a widespread mode of cell signaling, were reported in non-excitable cells for the first time more than 25 years ago. Their fundamental mechanism, based on the periodic Ca
2+ exchange between the endoplasmic reticulum and the cytoplasm, has been well characterized. However, how the kinetics of cytosolic Ca
2+ changes are related to the extent of a physiological response remains poorly understood. Here, we review data suggesting that the downstream targets of Ca
2+ are controlled not only by the frequency of Ca
2+ oscillations but also by the detailed characteristics of the oscillations, such as their duration, shape, or baseline level. Involvement of non-endoplasmic reticulum Ca
2+ stores, mainly mitochondria and the extracellular medium, participates in this fine tuning of Ca
2+ oscillations. The main characteristics of the Ca
2+ exchange fluxes with these compartments are also reviewed.
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Affiliation(s)
- Geneviève Dupont
- Unité de Chronobiologie Théorique, Faculté des Sciences, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Laurent Combettes
- Interactions Cellulaires et Physiopathologie Hépatique, UMR-S 1174, Université Paris Sud, Orsay, France
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114
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Liu JC, Liu J, Holmström KM, Menazza S, Parks RJ, Fergusson MM, Yu ZX, Springer DA, Halsey C, Liu C, Murphy E, Finkel T. MICU1 Serves as a Molecular Gatekeeper to Prevent In Vivo Mitochondrial Calcium Overload. Cell Rep 2016; 16:1561-1573. [PMID: 27477272 DOI: 10.1016/j.celrep.2016.07.011] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 03/24/2016] [Accepted: 07/03/2016] [Indexed: 01/10/2023] Open
Abstract
MICU1 is a component of the mitochondrial calcium uniporter, a multiprotein complex that also includes MICU2, MCU, and EMRE. Here, we describe a mouse model of MICU1 deficiency. MICU1(-/-) mitochondria demonstrate altered calcium uptake, and deletion of MICU1 results in significant, but not complete, perinatal mortality. Similar to afflicted patients, viable MICU1(-/-) mice manifest marked ataxia and muscle weakness. Early in life, these animals display a range of biochemical abnormalities, including increased resting mitochondrial calcium levels, altered mitochondrial morphology, and reduced ATP. Older MICU1(-/-) mice show marked, spontaneous improvement coincident with improved mitochondrial calcium handling and an age-dependent reduction in EMRE expression. Remarkably, deleting one allele of EMRE helps normalize calcium uptake while simultaneously rescuing the high perinatal mortality observed in young MICU1(-/-) mice. Together, these results demonstrate that MICU1 serves as a molecular gatekeeper preventing calcium overload and suggests that modulating the calcium uniporter could have widespread therapeutic benefits.
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Affiliation(s)
- Julia C Liu
- Center for Molecular Medicine, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Jie Liu
- Center for Molecular Medicine, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Kira M Holmström
- Center for Molecular Medicine, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Sara Menazza
- Systems Biology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Randi J Parks
- Systems Biology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Maria M Fergusson
- Center for Molecular Medicine, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Zu-Xi Yu
- Pathology Core, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Danielle A Springer
- Murine Phenotyping Core, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Charles Halsey
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Chengyu Liu
- Transgenic Core, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Elizabeth Murphy
- Systems Biology Center, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
| | - Toren Finkel
- Center for Molecular Medicine, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA.
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115
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Wagner S, De Bortoli S, Schwarzländer M, Szabò I. Regulation of mitochondrial calcium in plants versus animals. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3809-29. [PMID: 27001920 DOI: 10.1093/jxb/erw100] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Ca(2+) acts as an important cellular second messenger in eukaryotes. In both plants and animals, a wide variety of environmental and developmental stimuli trigger Ca(2+) transients of a specific signature that can modulate gene expression and metabolism. In animals, mitochondrial energy metabolism has long been considered a hotspot of Ca(2+) regulation, with a range of pathophysiology linked to altered Ca(2+) control. Recently, several molecular players involved in mitochondrial Ca(2+) signalling have been identified, including those of the mitochondrial Ca(2+) uniporter. Despite strong evidence for sophisticated Ca(2+) regulation in plant mitochondria, the picture has remained much less clear. This is currently changing aided by live imaging and genetic approaches which allow dissection of subcellular Ca(2+) dynamics and identification of the proteins involved. We provide an update on our current understanding in the regulation of mitochondrial Ca(2+) and signalling by comparing work in plants and animals. The significance of mitochondrial Ca(2+) control is discussed in the light of the specific metabolic and energetic needs of plant and animal cells.
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Affiliation(s)
- Stephan Wagner
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, D-53113 Bonn, Germany
| | - Sara De Bortoli
- Department of Biology and CNR Institute of Neurosciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy
| | - Markus Schwarzländer
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, D-53113 Bonn, Germany
| | - Ildikò Szabò
- Department of Biology and CNR Institute of Neurosciences, University of Padova, Viale G. Colombo 3, 35121 Padova, Italy
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116
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Jhun BS, Mishra J, Monaco S, Fu D, Jiang W, Sheu SS, O-Uchi J. The mitochondrial Ca2+ uniporter: regulation by auxiliary subunits and signal transduction pathways. Am J Physiol Cell Physiol 2016; 311:C67-80. [PMID: 27122161 DOI: 10.1152/ajpcell.00319.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Mitochondrial Ca(2+) homeostasis, the Ca(2+) influx-efflux balance, is responsible for the control of numerous cellular functions, including energy metabolism, generation of reactive oxygen species, spatiotemporal dynamics of Ca(2+) signaling, and cell growth and death. Recent discovery of the molecular identity of the mitochondrial Ca(2+) uniporter (MCU) provides new possibilities for application of genetic approaches to study the mitochondrial Ca(2+) influx mechanism in various cell types and tissues. In addition, the subsequent discovery of various auxiliary subunits associated with MCU suggests that mitochondrial Ca(2+) uptake is not solely regulated by a single protein (MCU), but likely by a macromolecular protein complex, referred to as the MCU-protein complex (mtCUC). Moreover, recent reports have shown the potential role of MCU posttranslational modifications in the regulation of mitochondrial Ca(2+) uptake through mtCUC. These observations indicate that mtCUCs form a local signaling complex at the inner mitochondrial membrane that could significantly regulate mitochondrial Ca(2+) handling, as well as numerous mitochondrial and cellular functions. In this review we discuss the current literature on mitochondrial Ca(2+) uptake mechanisms, with a particular focus on the structure and function of mtCUC, as well as its regulation by signal transduction pathways, highlighting current controversies and discrepancies.
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Affiliation(s)
- Bong Sook Jhun
- Cardiovascular Research Center, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island; and
| | - Jyotsna Mishra
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sarah Monaco
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Deming Fu
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Wenmin Jiang
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Shey-Shing Sheu
- Center for Translational Medicine, Department of Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jin O-Uchi
- Cardiovascular Research Center, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island; and
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117
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Tsai MF, Phillips CB, Ranaghan M, Tsai CW, Wu Y, Willliams C, Miller C. Dual functions of a small regulatory subunit in the mitochondrial calcium uniporter complex. eLife 2016; 5. [PMID: 27099988 PMCID: PMC4892889 DOI: 10.7554/elife.15545] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/19/2016] [Indexed: 01/19/2023] Open
Abstract
Mitochondrial Ca2+ uptake, a process crucial for bioenergetics and Ca2+ signaling, is catalyzed by the mitochondrial calcium uniporter. The uniporter is a multi-subunit Ca2+-activated Ca2+ channel, with the Ca2+ pore formed by the MCU protein and Ca2+-dependent activation mediated by MICU subunits. Recently, a mitochondrial inner membrane protein EMRE was identified as a uniporter subunit absolutely required for Ca2+ permeation. However, the molecular mechanism and regulatory purpose of EMRE remain largely unexplored. Here, we determine the transmembrane orientation of EMRE, and show that its known MCU-activating function is mediated by the interaction of transmembrane helices from both proteins. We also reveal a second function of EMRE: to maintain tight MICU regulation of the MCU pore, a role that requires EMRE to bind MICU1 using its conserved C-terminal polyaspartate tail. This dual functionality of EMRE ensures that all transport-competent uniporters are tightly regulated, responding appropriately to a dynamic intracellular Ca2+ landscape. DOI:http://dx.doi.org/10.7554/eLife.15545.001 Like all power plants, mitochondria – the compartments inside our cells that supply energy – must adjust their energy output to match fluctuations in demand. Inside cells, the levels of calcium ions in the cytoplasm often signal such demands. Mitochondria therefore control their calcium ion levels with tightly regulated, membrane-embedded proteins that move calcium ions into and out of the mitochondria. One of these membrane machines, the mitochondrial calcium uniporter (MCU) complex, is a "smart channel" that admits calcium ions into the mitochondria only when their cytoplasmic levels exceed a threshold. The MCU complex contains four essential proteins: MCU, which forms the pore through which the calcium ions enter the mitochondrion; MICU1 and MICU2, which act as “gatekeepers”, opening the pore only when the cell contains high levels of calcium ions; and EMRE, a small, mysterious protein. Why is EMRE required for the channel's operation, and how does it fit into the four-protein complex? By comparing EMRE proteins from different species, constructing mutant forms of EMRE, and recording calcium ion transport in mitochondria from cultured human cells, Tsai, Phillips et al. show that EMRE has two key roles. First, it snuggles up against the MCU protein and forms an essential part of the calcium ion-selective pore. Second, it acts as molecular glue to fix the calcium ion-sensing MICU gatekeepers to the pore. These two linked functions ensure that the MCU complex switches on only when the cell contains high levels of calcium ions, preventing the cell becoming catastrophically overloaded with calcium ions and cell death. Challenges for the future are to purify the MCU complex and reconstitute its ability to transport calcium ions from its component parts. This will help to determine the structure of the channel. DOI:http://dx.doi.org/10.7554/eLife.15545.002
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Affiliation(s)
- Ming-Feng Tsai
- Department of Biochemistry, Brandeis University, Waltham, United States.,Howard Hughes Medical Institute, Brandeis University, Waltham, United States
| | - Charles B Phillips
- Department of Biochemistry, Brandeis University, Waltham, United States.,Howard Hughes Medical Institute, Brandeis University, Waltham, United States
| | - Matthew Ranaghan
- Department of Biochemistry, Brandeis University, Waltham, United States
| | - Chen-Wei Tsai
- Department of Biochemistry, Brandeis University, Waltham, United States.,Howard Hughes Medical Institute, Brandeis University, Waltham, United States
| | - Yujiao Wu
- Department of Biochemistry, Brandeis University, Waltham, United States.,Howard Hughes Medical Institute, Brandeis University, Waltham, United States
| | - Carole Willliams
- Department of Biochemistry, Brandeis University, Waltham, United States.,Howard Hughes Medical Institute, Brandeis University, Waltham, United States
| | - Christopher Miller
- Department of Biochemistry, Brandeis University, Waltham, United States.,Howard Hughes Medical Institute, Brandeis University, Waltham, United States
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118
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La Rovere RML, Roest G, Bultynck G, Parys JB. Intracellular Ca(2+) signaling and Ca(2+) microdomains in the control of cell survival, apoptosis and autophagy. Cell Calcium 2016; 60:74-87. [PMID: 27157108 DOI: 10.1016/j.ceca.2016.04.005] [Citation(s) in RCA: 201] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 04/14/2016] [Accepted: 04/15/2016] [Indexed: 01/01/2023]
Abstract
The endoplasmic reticulum (ER), mitochondria and lysosomes are physically and/or functionally linked, establishing close contact sites between these organelles. As a consequence, Ca(2+) release events from the ER, the major intracellular Ca(2+)-storage organelle, have an immediate effect on the physiological function of mitochondria and lysosomes. Also, the lysosomes can act as a Ca(2+) source for Ca(2+) release into the cytosol, thereby influencing ER-based Ca(2+) signaling. Given the important role for mitochondria and lysosomes in cell survival, cell death and cell adaptation processes, it has become increasingly clear that Ca(2+) signals from or towards these organelles impact these processes. In this review, we discuss the most recent insights in the emerging role of Ca(2+) signaling in cellular survival by controlling basal mitochondrial bioenergetics and by regulating apoptosis, a mitochondrial process, and autophagy, a lysosomal process, in response to cell damage and cell stress.
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Affiliation(s)
- Rita M L La Rovere
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, BE-3000 Leuven, Belgium
| | - Gemma Roest
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, BE-3000 Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, BE-3000 Leuven, Belgium.
| | - Jan B Parys
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine & Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, BE-3000 Leuven, Belgium.
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119
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Carraretto L, Checchetto V, De Bortoli S, Formentin E, Costa A, Szabó I, Teardo E. Calcium Flux across Plant Mitochondrial Membranes: Possible Molecular Players. FRONTIERS IN PLANT SCIENCE 2016; 7:354. [PMID: 27065186 PMCID: PMC4814809 DOI: 10.3389/fpls.2016.00354] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 03/07/2016] [Indexed: 05/24/2023]
Abstract
Plants, being sessile organisms, have evolved the ability to integrate external stimuli into metabolic and developmental signals. A wide variety of signals, including abiotic, biotic, and developmental stimuli, were observed to evoke specific spatio-temporal Ca(2+) transients which are further transduced by Ca(2+) sensor proteins into a transcriptional and metabolic response. Most of the research on Ca(2+) signaling in plants has been focused on the transport mechanisms for Ca(2+) across the plasma- and the vacuolar membranes as well as on the components involved in decoding of cytoplasmic Ca(2+) signals, but how intracellular organelles such as mitochondria are involved in the process of Ca(2+) signaling is just emerging. The combination of the molecular players and the elicitors of Ca(2+) signaling in mitochondria together with newly generated detection systems for measuring organellar Ca(2+) concentrations in plants has started to provide fruitful grounds for further discoveries. In the present review we give an updated overview of the currently identified/hypothesized pathways, such as voltage-dependent anion channels, homologs of the mammalian mitochondrial uniporter (MCU), LETM1, a plant glutamate receptor family member, adenine nucleotide/phosphate carriers and the permeability transition pore (PTP), that may contribute to the transport of Ca(2+) across the outer and inner mitochondrial membranes in plants. We briefly discuss the relevance of the mitochondrial Ca(2+) homeostasis for ensuring optimal bioenergetic performance of this organelle.
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Affiliation(s)
| | - Vanessa Checchetto
- Department of Biology, University of PadovaPadova, Italy
- Department of Biomedical Sciences, University of PadovaPadova, Italy
| | | | - Elide Formentin
- Department of Biology, University of PadovaPadova, Italy
- Department of Life Science and Biotechnology, University of FerraraFerrara, Italy
| | - Alex Costa
- Department of Biosciences, University of MilanMilan, Italy
- CNR, Institute of Biophysics, Consiglio Nazionale delle RicercheMilan, Italy
| | - Ildikó Szabó
- Department of Biology, University of PadovaPadova, Italy
- CNR, Institute of NeurosciencesPadova, Italy
| | - Enrico Teardo
- Department of Biology, University of PadovaPadova, Italy
- CNR, Institute of NeurosciencesPadova, Italy
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120
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Analysis of the structure and function of EMRE in a yeast expression system. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:831-9. [PMID: 27001609 DOI: 10.1016/j.bbabio.2016.03.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 03/08/2016] [Accepted: 03/17/2016] [Indexed: 11/21/2022]
Abstract
The mitochondrial calcium uniporter (MCU) complex is a highly-selective calcium channel, and this complex is believed to consist of a pore-forming subunit, MCU, and its regulatory subunits. As yeast cells lack orthologues of the mammalian proteins, the yeast expression system for the mammalian calcium uniporter subunits is useful for investigating their functions. We here established a yeast expression system for the native-form mouse MCU and 4 other subunits. This expression system enabled us to precisely reconstitute the properties of the mammalian MCU complex in yeast mitochondria. Using this expression system, we analyzed the essential MCU regulator (EMRE), which is a key subunit for Ca(2+) uptake but whose functions and structure remain unclear. The topology of EMRE was revealed: its N- and C-termini projected into the matrix and the inter membrane space, respectively. The expression of EMRE alone was insufficient for Ca(2+) uptake; and co-expression of MCU with EMRE was necessary. EMRE was independent of the protein levels of other subunits, indicating that EMRE was not a protein-stabilizing factor. Deletion of acidic amino acids conserved in EMRE did not significantly affect Ca(2+) uptake; thus, EMRE did not have basic properties of ion channels such as ion-selectivity filtration and ion concentration. Meanwhile, EMRE closely interacted with the MCU on both sides of the inner membrane, and this interaction was essential for Ca(2+) uptake. This close interaction suggested that EMRE might be a structural factor for opening of the MCU-forming pore.
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Mammucari C, Raffaello A, Vecellio Reane D, Rizzuto R. Molecular structure and pathophysiological roles of the Mitochondrial Calcium Uniporter. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2457-64. [PMID: 26968367 DOI: 10.1016/j.bbamcr.2016.03.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/24/2016] [Accepted: 03/01/2016] [Indexed: 01/21/2023]
Abstract
Mitochondrial Ca(2+) uptake regulates a wide array of cell functions, from stimulation of aerobic metabolism and ATP production in physiological settings, to induction of cell death in pathological conditions. The molecular identity of the Mitochondrial Calcium Uniporter (MCU), the highly selective channel responsible for Ca(2+) entry through the IMM, has been described less than five years ago. Since then, research has been conducted to clarify the modulation of its activity, which relies on the dynamic interaction with regulatory proteins, and its contribution to the pathophysiology of organs and tissues. Particular attention has been placed on characterizing the role of MCU in cardiac and skeletal muscles. In this review we summarize the molecular structure and regulation of the MCU complex in addition to its pathophysiological role, with particular attention to striated muscle tissues. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Affiliation(s)
| | - Anna Raffaello
- Department of Biomedical Sciences, University of Padua, 35131, Italy.
| | | | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padua, 35131, Italy; Neuroscience Institute, National Research Council, Padua 35131, Italy.
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Intramitochondrial Ca 2+ Sensing by EMRE: The Matrix Outlook on Stimulus-Metabolism Coupling. Mol Cell 2016; 61:646-647. [DOI: 10.1016/j.molcel.2016.02.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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123
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The Roles of Mitochondrial Cation Channels Under Physiological Conditions and in Cancer. Handb Exp Pharmacol 2016; 240:47-69. [PMID: 27995386 DOI: 10.1007/164_2016_92] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Bioenergetics has become central to our understanding of pathological mechanisms as well as the development of new therapeutic strategies and as a tool for gauging disease progression in neurodegeneration, diabetes, cancer, and cardiovascular disease. The view is emerging that inner mitochondrial membrane (IMM) cation channels have a profound effect on mitochondrial function and, consequently, on the metabolic state and survival of the whole cell. Since disruption of the sustained integrity of mitochondria is strongly linked to human disease, pharmacological intervention offers a new perspective concerning neurodegenerative and cardiovascular diseases as well as cancer. This review summarizes our current knowledge regarding IMM cation channels and their roles under physiological conditions as well as in cancer, with special emphasis on potassium channels and the mammalian mitochondrial calcium uniporter.
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