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Spolaor S, Rovetta M, Nobile MS, Cazzaniga P, Tisi R, Besozzi D. Modeling Calcium Signaling in S. cerevisiae Highlights the Role and Regulation of the Calmodulin-Calcineurin Pathway in Response to Hypotonic Shock. Front Mol Biosci 2022; 9:856030. [PMID: 35664674 PMCID: PMC9158465 DOI: 10.3389/fmolb.2022.856030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 04/04/2022] [Indexed: 01/17/2023] Open
Abstract
Calcium homeostasis and signaling processes in Saccharomyces cerevisiae, as well as in any eukaryotic organism, depend on various transporters and channels located on both the plasma and intracellular membranes. The activity of these proteins is regulated by a number of feedback mechanisms that act through the calmodulin-calcineurin pathway. When exposed to hypotonic shock (HTS), yeast cells respond with an increased cytosolic calcium transient, which seems to be conditioned by the opening of stretch-activated channels. To better understand the role of each channel and transporter involved in the generation and recovery of the calcium transient—and of their feedback regulations—we defined and analyzed a mathematical model of the calcium signaling response to HTS in yeast cells. The model was validated by comparing the simulation outcomes with calcium concentration variations before and during the HTS response, which were observed experimentally in both wild-type and mutant strains. Our results show that calcium normally enters the cell through the High Affinity Calcium influx System and mechanosensitive channels. The increase of the plasma membrane tension, caused by HTS, boosts the opening probability of mechanosensitive channels. This event causes a sudden calcium pulse that is rapidly dissipated by the activity of the vacuolar transporter Pmc1. According to model simulations, the role of another vacuolar transporter, Vcx1, is instead marginal, unless calcineurin is inhibited or removed. Our results also suggest that the mechanosensitive channels are subject to a calcium-dependent feedback inhibition, possibly involving calmodulin. Noteworthy, the model predictions are in accordance with literature results concerning some aspects of calcium homeostasis and signaling that were not specifically addressed within the model itself, suggesting that it actually depicts all the main cellular components and interactions that constitute the HTS calcium pathway, and thus can correctly reproduce the shaping of the calcium signature by calmodulin- and calcineurin-dependent complex regulations. The model predictions also allowed to provide an interpretation of different regulatory schemes involved in calcium handling in both wild-type and mutants yeast strains. The model could be easily extended to represent different calcium signals in other eukaryotic cells.
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Affiliation(s)
- Simone Spolaor
- Department of Informatics, Systems and Communication, University of Milano-Bicocca, Milan, Italy
| | - Mattia Rovetta
- Department of Informatics, Systems and Communication, University of Milano-Bicocca, Milan, Italy
| | - Marco S. Nobile
- Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University of Venice, Venice, Italy
- Bicocca Bioinformatics, Biostatistics and Bioimaging Centre—B4, Milan, Italy
- SYSBIO/ISBE.IT Centre of Systems Biology, Milan, Italy
| | - Paolo Cazzaniga
- Bicocca Bioinformatics, Biostatistics and Bioimaging Centre—B4, Milan, Italy
- SYSBIO/ISBE.IT Centre of Systems Biology, Milan, Italy
- Department of Human and Social Sciences, University of Bergamo, Bergamo, Italy
| | - Renata Tisi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
- *Correspondence: Renata Tisi, ; Daniela Besozzi,
| | - Daniela Besozzi
- Department of Informatics, Systems and Communication, University of Milano-Bicocca, Milan, Italy
- Bicocca Bioinformatics, Biostatistics and Bioimaging Centre—B4, Milan, Italy
- SYSBIO/ISBE.IT Centre of Systems Biology, Milan, Italy
- *Correspondence: Renata Tisi, ; Daniela Besozzi,
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2
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Hamilton J, Brustovetsky T, Rysted JE, Lin Z, Usachev YM, Brustovetsky N. Deletion of mitochondrial calcium uniporter incompletely inhibits calcium uptake and induction of the permeability transition pore in brain mitochondria. J Biol Chem 2018; 293:15652-15663. [PMID: 30154242 DOI: 10.1074/jbc.ra118.002926] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 08/22/2018] [Indexed: 11/06/2022] Open
Abstract
Ca2+ influx into mitochondria is mediated by the mitochondrial calcium uniporter (MCU), whose identity was recently revealed as a 40-kDa protein that along with other proteins forms the mitochondrial Ca2+ uptake machinery. The MCU is a Ca2+-conducting channel spanning the inner mitochondrial membrane. Here, deletion of the MCU completely inhibited Ca2+ uptake in liver, heart, and skeletal muscle mitochondria. However, in brain nonsynaptic and synaptic mitochondria from neuronal somata/glial cells and nerve terminals, respectively, the MCU deletion slowed, but did not completely block, Ca2+ uptake. Under resting conditions, brain MCU-KO mitochondria remained polarized, and in brain MCU-KO mitochondria, the electrophoretic Ca2+ ionophore ETH129 significantly accelerated Ca2+ uptake. The residual Ca2+ uptake in brain MCU-KO mitochondria was insensitive to inhibitors of mitochondrial Na+/Ca2+ exchanger and ryanodine receptor (CGP37157 and dantrolene, respectively), but was blocked by the MCU inhibitor Ru360. Respiration of WT and MCU-KO brain mitochondria was similar except that for mitochondria that oxidized pyruvate and malate, Ca2+ more strongly inhibited respiration in WT than in MCU-KO mitochondria. Of note, the MCU deletion significantly attenuated but did not completely prevent induction of the permeability transition pore (PTP) in brain mitochondria. Expression level of cyclophilin D and ATP content in mitochondria, two factors that modulate PTP induction, were unaffected by MCU-KO, whereas ADP was lower in MCU-KO than in WT brain mitochondria. Our results suggest the presence of an MCU-independent Ca2+ uptake pathway in brain mitochondria that mediates residual Ca2+ influx and induction of PTP in a fraction of the mitochondrial population.
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Affiliation(s)
| | | | - Jacob E Rysted
- the Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Zhihong Lin
- the Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Yuriy M Usachev
- the Department of Pharmacology, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Nickolay Brustovetsky
- From the Department of Pharmacology and Toxicology and .,the Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202 and
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3
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Kamei Y, Koushi M, Aoyama Y, Asakai R. The yeast mitochondrial permeability transition is regulated by reactive oxygen species, endogenous Ca 2+ and Cpr3, mediating cell death. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1313-1326. [PMID: 30031690 DOI: 10.1016/j.bbabio.2018.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 07/13/2018] [Accepted: 07/16/2018] [Indexed: 11/29/2022]
Abstract
We investigated the properties of the permeability transition pore (PTP) in Saccharomyces cerevisiae in agar-embedded mitochondria (AEM) and agar-embedded cells (AEC) and its role in yeast death. In AEM, ethanol-induced pore opening, as indicated by the release of calcein and mitochondrial membrane depolarization, can be inhibited by CsA, by Cpr3 deficiency, and by the antioxidant glutathione. Notably, the pore opening is inhibited, when mitochondria are preloaded by EGTA or Fluo3 to chelate matrix Ca2+, or are pretreated with 4-Br A23187 to extract matrix Ca2+, prior to agar-embedding, or when pore opening is induced in the presence of EGTA; opened pores are re-closed by sequential treatment with CsA, 4-Br A23187 plus EGTA and NADH, indicating endogenous matrix Ca2+ involvement. CsA also inhibits the pore opening with low conductance triggered by exogenous Ca2+ transport with ETH129. In AEC, the treatment of tert-butylhydroperoxide, a pro-oxidant that triggers transient pore opening in high conductance in AEM, induces yeast death, which is also dependent on CsA and Cpr3. Furthermore, AEMs from mutants lacking three ADP/ATP carrier (AAC) isoforms and with defective ATP synthase dimerization exhibit high and low conductance pore openings with CsA sensitivity, respectively. Collectively, these data show that the yeast PTP is regulated by Cpr3, endogenous matrix Ca2+, and reactive oxygen species, and that it is involved in yeast death; furthermore, ATP synthase dimers play a key role in CsA-sensitive pore formation, while AACs are dispensable.
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Affiliation(s)
- Yoshiko Kamei
- Department of Morphophysiology, Faculty of Pharmaceutical Sciences, Josai International University, 1 Gumyo, Togane, Chiba 283-8555, Japan
| | - Masami Koushi
- Department of Morphophysiology, Faculty of Pharmaceutical Sciences, Josai International University, 1 Gumyo, Togane, Chiba 283-8555, Japan
| | - Yasunori Aoyama
- Department of Morphophysiology, Faculty of Pharmaceutical Sciences, Josai International University, 1 Gumyo, Togane, Chiba 283-8555, Japan
| | - Rei Asakai
- Department of Morphophysiology, Faculty of Pharmaceutical Sciences, Josai International University, 1 Gumyo, Togane, Chiba 283-8555, Japan.
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4
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Selles B, Michaud C, Xiong TC, Leblanc O, Ingouff M. Arabidopsis pollen tube germination and growth depend on the mitochondrial calcium uniporter complex. THE NEW PHYTOLOGIST 2018; 219:58-65. [PMID: 29701876 DOI: 10.1111/nph.15189] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 03/27/2018] [Indexed: 05/18/2023]
Abstract
The mitochondrial calcium uniporter complex (MCUc) was recently characterized in details in metazoans and consists of pore-forming units (MCUs) and regulatory factors that channel calcium (Ca2+ ) ion into the mitochondria. MCUs participate in many stress and developmentally related processes involving Ca2+ . Although multiple homologues of MCUs and one regulatory subunit are usually present in plants, the first functional characterization and contribution to Ca2+ related processes of these proteins have been reported recently. Here, we focused on two predicted Arabidopsis MCUs and studied their role in the germination and the growth of pollen tube, a tip-growing cell type highly dependent on Ca2+ homeostasis. Heterologous expression of MCU1 or MCU2 in yeast is sufficient to generate a mitochondrial Ca2+ influx. MCU1 and MCU2 fluorescent reporters are co-expressed in the vegetative cell mitochondria of the pollen grain but are undetectable in the embryo sac. We demonstrate that MCU1 and MCU2 can form a heterotypic complex. Phenotypic analyses revealed an impaired pollen tube germination and growth in vitro only for the mcu2 mutants suggesting a predominant role of MCU2. Our results show that mitochondrial Ca2+ controlled by MCUs is an additional player in Arabidopsis pollen tube germination and growth.
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Affiliation(s)
- Benjamin Selles
- DIADE, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
| | - Caroline Michaud
- DIADE, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
| | - Tou-Cheu Xiong
- Institut National de la Recherche Agronomique (UMR 386), BPMP, Université de Montpellier, Centre National de la Recherche Scientifique (UMR 5004), Institut National de la Recherche Agronomique, Montpellier SupAgro, F-34060, Montpellier Cedex 2, France
| | - Olivier Leblanc
- DIADE, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
| | - Mathieu Ingouff
- DIADE, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
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5
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Gómez-Suaga P, Bravo-San Pedro JM, González-Polo RA, Fuentes JM, Niso-Santano M. ER-mitochondria signaling in Parkinson's disease. Cell Death Dis 2018; 9:337. [PMID: 29497039 PMCID: PMC5832754 DOI: 10.1038/s41419-017-0079-3] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/14/2017] [Accepted: 09/20/2017] [Indexed: 02/06/2023]
Abstract
Mitochondria form close physical contacts with a specialized domain of the endoplasmic reticulum (ER), known as the mitochondria-associated membrane (MAM). This association constitutes a key signaling hub to regulate several fundamental cellular processes. Alterations in ER-mitochondria signaling have pleiotropic effects on a variety of intracellular events resulting in mitochondrial damage, Ca2+ dyshomeostasis, ER stress and defects in lipid metabolism and autophagy. Intriguingly, many of these cellular processes are perturbed in neurodegenerative diseases. Furthermore, increasing evidence highlights that ER-mitochondria signaling contributes to these diseases, including Parkinson's disease (PD). PD is the second most common neurodegenerative disorder, for which effective mechanism-based treatments remain elusive. Several PD-related proteins localize at mitochondria or MAM and have been shown to participate in ER-mitochondria signaling regulation. Likewise, PD-related mutations have been shown to damage this signaling. Could ER-mitochondria associations be the link between pathogenic mechanisms involved in PD, providing a common mechanism? Would this provide a pharmacological target for treating this devastating disease? In this review, we aim to summarize the current knowledge of ER-mitochondria signaling and the recent evidence concerning damage to this signaling in PD.
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Affiliation(s)
- Patricia Gómez-Suaga
- Department of Basic and Clinical Neurosciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 9RX, UK
| | - José M Bravo-San Pedro
- Equipe 11 Labellisée Ligue contre le Cancer, Centre de Recherche des Cordeliers, 75006, Paris, France
- INSERM U1138, 75006, Paris, France
- Université Paris Descartes/Paris V, Sorbonne Paris Cité, 75006, Paris, France
- Université Pierre et Marie Curie/Paris VI, 75006, Paris, France
- Gustave Roussy Comprehensive Cancer Institute, 94805, Villejuif, France
| | - Rosa A González-Polo
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 18100, Granada, Spain
- Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura. Avda. De la Universidad S/N, C.P, 10003, Cáceres, Spain
| | - José M Fuentes
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 18100, Granada, Spain.
- Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura. Avda. De la Universidad S/N, C.P, 10003, Cáceres, Spain.
| | - Mireia Niso-Santano
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas (CIBERNED), 18100, Granada, Spain.
- Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura. Avda. De la Universidad S/N, C.P, 10003, Cáceres, Spain.
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6
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Nathan SR, Pino NW, Arduino DM, Perocchi F, MacMillan SN, Wilson JJ. Synthetic Methods for the Preparation of a Functional Analogue of Ru360, a Potent Inhibitor of Mitochondrial Calcium Uptake. Inorg Chem 2017; 56:3123-3126. [DOI: 10.1021/acs.inorgchem.6b03108] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sarah R. Nathan
- Department of Chemistry
and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Nicholas W. Pino
- Department of Chemistry
and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Daniela M. Arduino
- Gene Center, Department of Biochemistry, Ludwig-Maximilans Universität München, Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Fabiana Perocchi
- Gene Center, Department of Biochemistry, Ludwig-Maximilans Universität München, Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Samantha N. MacMillan
- Department of Chemistry
and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Justin J. Wilson
- Department of Chemistry
and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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7
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Abstract
Ruthenium is seldom mentioned in microbiology texts, due to the fact that this metal has no known, essential roles in biological systems, nor is it generally considered toxic. Since the fortuitous discovery of cisplatin, first as an antimicrobial agent and then later employed widely as an anticancer agent, complexes of other platinum group metals, such as ruthenium, have attracted interest for their medicinal properties. Here, we review at length how ruthenium complexes have been investigated as potential antimicrobial, antiparasitic and chemotherapeutic agents, in addition to their long and well-established roles as biological stains and inhibitors of calcium channels. Ruthenium complexes are also employed in a surprising number of biotechnological roles. It is in the employment of ruthenium complexes as antimicrobial agents and alternatives or adjuvants to more traditional antibiotics, that we expect to see the most striking developments in the future. Such novel contributions from organometallic chemistry are undoubtedly sorely needed to address the antimicrobial resistance crisis and the slow appearance on the market of new antibiotics.
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8
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Calcium signaling in pancreatic ductal epithelial cells: an old friend and a nasty enemy. Cell Calcium 2014; 55:337-45. [PMID: 24602604 DOI: 10.1016/j.ceca.2014.02.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 02/04/2014] [Accepted: 02/05/2014] [Indexed: 12/20/2022]
Abstract
Ductal epithelial cells of the exocrine pancreas secrete HCO3(-) rich, alkaline pancreatic juice, which maintains the intraluminal pH and washes the digestive enzymes out from the ductal system. Importantly, damage of this secretory process can lead to pancreatic diseases such as acute and chronic pancreatitis. Intracellular Ca(2+) signaling plays a central role in the physiological regulation of HCO3(-) secretion, however uncontrolled Ca(2+) release can lead to intracellular Ca(2+) overload and toxicity, including mitochondrial damage and impaired ATP production. Recent findings suggest that the most common pathogenic factors leading to acute pancreatitis, such as bile acids, or ethanol and ethanol metabolites can evoke different types of intracellular Ca(2+) signals, which can stimulate or inhibit ductal HCO3(-) secretion. Therefore, understanding the intracellular Ca(2+) pathways and the mechanisms which can switch a good signal to a bad signal in pancreatic ductal epithelial cells are crucially important. This review summarizes the variety of Ca(2+) signals both in physiological and pathophysiological aspects and highlight molecular targets which may strengthen our old friend or release our nasty enemy.
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9
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Maléth J, Rakonczay Z, Venglovecz V, Dolman NJ, Hegyi P. Central role of mitochondrial injury in the pathogenesis of acute pancreatitis. Acta Physiol (Oxf) 2013; 207:226-35. [PMID: 23167280 DOI: 10.1111/apha.12037] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 10/26/2012] [Accepted: 10/30/2012] [Indexed: 12/11/2022]
Abstract
Acute pancreatitis is an inflammatory disease with no specific treatment. One of the main reasons behind the lack of specific therapy is that the pathogenesis of acute pancreatitis is poorly understood. During the development of acute pancreatitis, the disease-inducing factors can damage both cell types of the exocrine pancreas, namely the acinar and ductal cells. Because damage of either of the cell types can contribute to the inflammation, it is crucial to find common intracellular mechanisms that can be targeted by pharmacological therapies. Despite the many differences, recent studies revealed that the most common factors that induce pancreatitis cause mitochondrial damage with the consequent breakdown of bioenergetics, that is, ATP depletion in both cell types. In this review, we summarize our knowledge of mitochondrial function and damage within both pancreatic acinar and ductal cells. We also suggest that colloidal ATP delivery systems for pancreatic energy supply may be able to protect acinar and ductal cells from cellular damage in the early phase of the disease. An effective energy delivery system combined with the prevention of further mitochondrial damage may, for the first time, open up the possibility of pharmacological therapy for acute pancreatitis, leading to reduced disease severity and mortality.
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Affiliation(s)
- J. Maléth
- First Department of Medicine; University of Szeged; Szeged; Hungary
| | - Z. Rakonczay
- First Department of Medicine; University of Szeged; Szeged; Hungary
| | - V. Venglovecz
- Department of Pharmacology and Pharmacotherapy; University of Szeged; Szeged; Hungary
| | - N. J. Dolman
- Molecular Probes Labelling and Detection Technologies; Life Technologies Corporation; Eugene; OR; USA
| | - P. Hegyi
- First Department of Medicine; University of Szeged; Szeged; Hungary
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10
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Fedoseeva IV, Pjatricas DV, Varakina NN, Rusaleva TM, Stepanov AV, Rikhvanov EG, Borovskii GB, Voinikov VK. Effect of amiodarone on thermotolerance and Hsp104p synthesis in the yeast Saccharomyces cerevisiae. BIOCHEMISTRY (MOSCOW) 2012; 77:78-86. [DOI: 10.1134/s0006297912010099] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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Webb SE, Rogers KL, Karplus E, Miller AL. The use of aequorins to record and visualize Ca(2+) dynamics: from subcellular microdomains to whole organisms. Methods Cell Biol 2010; 99:263-300. [PMID: 21035690 DOI: 10.1016/b978-0-12-374841-6.00010-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In this chapter, we describe the practical aspects of measuring [Ca(2+)] transients that are generated in a particular cytoplasmic domain, or within a specific organelle or its periorganellar environment, using bioluminescent, genetically encoded and targeted Ca(2+) reporters, especially those based on apoaequorin. We also list examples of the organisms, tissues, and cells that have been transfected with apoaequorin or an apoaequorin-BRET complex, as well as of the organelles and subcellular domains that have been specifically targeted with these bioluminescent Ca(2+) reporters. In addition, we summarize the various techniques used to load the apoaequorin cofactor, coelenterazine, and its analogs into cells, tissues, and intact organisms, and we describe recent advances in the detection and imaging technologies that are currently being used to measure and visualize the luminescence generated by the aequorin-Ca(2+) reaction within these various cytoplasmic domains and subcellular compartments.
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Affiliation(s)
- Sarah E Webb
- Biochemistry and Cell Biology Section and State Key Laboratory of Molecular Neuroscience, Division of Life Science, HKUST, Clear Water Bay, Kowloon, Hong Kong, PR China
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12
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Traba J, Froschauer EM, Wiesenberger G, Satrústegui J, Del Arco A. Yeast mitochondria import ATP through the calcium-dependent ATP-Mg/Pi carrier Sal1p, and are ATP consumers during aerobic growth in glucose. Mol Microbiol 2008; 69:570-85. [PMID: 18485069 DOI: 10.1111/j.1365-2958.2008.06300.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sal1p, a novel Ca2+-dependent ATP-Mg/Pi carrier, is essential in yeast lacking all adenine nucleotide translocases. By targeting luciferase to the mitochondrial matrix to monitor mitochondrial ATP levels, we show in isolated mitochondria that both ATP-Mg and free ADP are taken up by Sal1p with a K(m) of 0.20 +/- 0.03 mM and 0.28 +/- 0.06 mM respectively. Nucleotide transport along Sal1p is strictly Ca2+ dependent. Ca2+ increases the V(max) with a S(0.5) of 15 muM, and no changes in the K(m) for ATP-Mg. Glucose sensing in yeast generates Ca2+ transients involving Ca2+ influx from the external medium. We find that carbon-deprived cells respond to glucose with an immediate increase in mitochondrial ATP levels which is not observed in the presence of EGTA or in Sal1p-deficient cells. Moreover, we now report that during normal aerobic growth on glucose, yeast mitochondria import ATP from the cytosol and hydrolyse it through H+-ATP synthase. We identify two pathways for ATP uptake in mitochondria, the ADP/ATP carriers and Sal1p. Thus, during exponential growth on glucose, mitochondria are ATP consumers, as those from cells growing in anaerobic conditions or deprived of mitochondrial DNA which depend on cytosolic ATP and mitochondrial ATPase working in reverse to generate a mitochondrial membrane potential. In conclusion, the results show that growth on glucose requires ATP hydrolysis in mitochondria and recruits Sal1p as a Ca2+-dependent mechanism to import ATP-Mg from the cytosol. Whether this mechanism is used under similar settings in higher eukaryotes is an open question.
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Affiliation(s)
- Javier Traba
- Departamento de Biologia Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, CIBER de Enfermedades Raras (CIBERER), Universidad Autónoma, Madrid, Spain
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13
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Satrústegui J, Pardo B, Del Arco A. Mitochondrial Transporters as Novel Targets for Intracellular Calcium Signaling. Physiol Rev 2007; 87:29-67. [PMID: 17237342 DOI: 10.1152/physrev.00005.2006] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ca2+signaling in mitochondria is important to tune mitochondrial function to a variety of extracellular stimuli. The main mechanism is Ca2+entry in mitochondria via the Ca2+uniporter followed by Ca2+activation of three dehydrogenases in the mitochondrial matrix. This results in increases in mitochondrial NADH/NAD ratios and ATP levels and increased substrate uptake by mitochondria. We review evidence gathered more than 20 years ago and recent work indicating that substrate uptake, mitochondrial NADH/NAD ratios, and ATP levels may be also activated in response to cytosolic Ca2+signals via a mechanism that does not require the entry of Ca2+in mitochondria, a mechanism depending on the activity of Ca2+-dependent mitochondrial carriers (CaMC). CaMCs fall into two groups, the aspartate-glutamate carriers (AGC) and the ATP-Mg/Picarriers, also named SCaMC (for short CaMC). The two mammalian AGCs, aralar and citrin, are members of the malate-aspartate NADH shuttle, and citrin, the liver AGC, is also a member of the urea cycle. Both types of CaMCs are activated by Ca2+in the intermembrane space and function together with the Ca2+uniporter in decoding the Ca2+signal into a mitochondrial response.
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Affiliation(s)
- Jorgina Satrústegui
- Departamento de Biología Molecular Centro de Biología Molecular "Severo Ochoa" UAM-CSIC, Facultad de Ciencias, Universidad Autónoma, Madrid, Spain.
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14
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Bradshaw PC, Pfeiffer DR. Release of Ca2+ and Mg2+ from yeast mitochondria is stimulated by increased ionic strength. BMC BIOCHEMISTRY 2006; 7:4. [PMID: 16460565 PMCID: PMC1386685 DOI: 10.1186/1471-2091-7-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Accepted: 02/06/2006] [Indexed: 11/10/2022]
Abstract
Background Divalent cations are required for many essential functions of mitochondrial metabolism. Yet the transporters that mediate the flux of these molecules into and out of the mitochondrion remain largely unknown. Previous studies in yeast have led to the molecular identification of a component of the major mitochondrial electrophoretic Mg2+ uptake system in this organism as well as a functional mammalian homolog. Other yeast mitochondrial studies have led to the characterization of an equilibrative fatty acid-stimulated Ca2+ transport activity. To gain a deeper understanding of the regulation of mitochondrial divalent cation levels we further characterized the efflux of Ca2+ and Mg2+ from yeast mitochondria. Results When isolated mitochondria from the yeast Saccharomyces cerevisiae were suspended in a salt-based suspension medium, Ca2+ and Mg2+ were released from the matrix space. Release did not spontaneously occur in a non-ionic mannitol media. When energized mitochondria were suspended in a mannitol medium in the presence of Ca2+ they were able to accumulate Ca2+ by the addition of the electrogenic Ca2+ ionophore ETH-129. However, in a KCl or choline Cl medium under the same conditions, they were unable to retain the Ca2+ that was taken up due to the activation of the Ca2+ efflux pathway, although a substantial membrane potential driving Ca2+ uptake was maintained. This Ca2+ efflux was independent of fatty acids, which have previously been shown to activate Ca2+ transport. Endogenous mitochondrial Mg2+ was also released when mitochondria were suspended in an ionic medium, but was retained in mitochondria upon fatty acid addition. When suspended in a mannitol medium, metal chelators released mitochondrial Mg2+, supporting the existence of an external divalent cation-binding site regulating release. Matrix space Mg2+ was also slowly released from mitochondria by the addition of Ca2+, respiratory substrates, increasing pH, or the nucleotides ATP, ADP, GTP, and ATP-gamma-S. Conclusion In isolated yeast mitochondria Ca2+ and Mg2+ release was activated by increased ionic strength. Free nucleotides, metal ion chelators, and increased pH also stimulated release. In yeast cells this release is likely an important mechanism in the regulation of mitochondrial matrix space divalent cation concentrations.
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Affiliation(s)
| | - Douglas R Pfeiffer
- Department of Molecular and Cellular Biochemistry, Department of Internal Medicine, Institute for Mitochondrial Biology, The Ohio State University, Columbus, OH, USA
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Uccelletti D, Farina F, Pinton P, Goffrini P, Mancini P, Talora C, Rizzuto R, Palleschi C. The Golgi Ca2+-ATPase KlPmr1p function is required for oxidative stress response by controlling the expression of the heat-shock element HSP60 in Kluyveromyces lactis. Mol Biol Cell 2005; 16:4636-47. [PMID: 16030259 PMCID: PMC1237070 DOI: 10.1091/mbc.e05-02-0138] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Golgi P-type Ca2+-ATPase, Pmr1p, is the major player for calcium homeostasis in yeast. The inactivation of KlPMR1 in Kluyveromyces lactis leads to high pleiotropic phenotypes that include reduced glycosylation, cell wall defects, and alterations of mitochondrial metabolism. In this article we found that cells lacking KlPmr1p have a morphologically altered mitochondrial network and that mitochondria (m) from Klpmr1delta cells accumulate Ca2+ more slowly and reach a lower [Ca2+]m level, when exposed to [Ca2+] < 5 microM, than wild-type cells. The Klpmr1delta cells also exhibit traits of ongoing oxidative stress and present hyperphosphorylation of KlHog1p, the hallmark for the activation of stress response pathways. The mitochondrial chaperone KlHsp60 acts as a multicopy suppressor of phenotypes that occur in cells lacking the Ca2+-ATPase, including relief from oxidative stress and recovery of cell wall thickness and functionality. Inhibition of KlPMR1 function decreases KlHSP60 expression at both mRNA and protein levels. Moreover, KlPRM1 loss of function correlates with both decreases in HSF DNA binding activity and KlHSP60 expression. We suggest a role for KlPMR1 in HSF DNA binding activity, which is required for proper KlHSP60 expression, a key step in oxidative stress response.
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Affiliation(s)
- Daniela Uccelletti
- Department of Developmental and Cell Biology, University of Rome La Sapienza, 00185 Rome, Italy
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