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Jiang Y, Ding P. Calcium signaling in plant immunity: a spatiotemporally controlled symphony. TRENDS IN PLANT SCIENCE 2023; 28:74-89. [PMID: 36504136 DOI: 10.1016/j.tplants.2022.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 11/04/2022] [Accepted: 11/04/2022] [Indexed: 06/17/2023]
Abstract
Calcium ions (Ca2+) are prominent intracellular messengers in all eukaryotic cells. Recent studies have emphasized the crucial roles of Ca2+ in plant immunity. Here, we review the latest progress on the spatiotemporal control of Ca2+ function in plant immunity. We discuss discoveries of how Ca2+ influx is triggered upon the activation of immune receptors, how Ca2+-permeable channels are activated, how Ca2+ signals are decoded inside plant cells, and how these signals are switched off. Despite recent advances, many open questions remain and we highlight the existing toolkit and the new technologies to address the outstanding questions of Ca2+ signaling in plant immunity.
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Affiliation(s)
- Yuxiang Jiang
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
| | - Pingtao Ding
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, Leiden 2333, BE, The Netherlands.
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2
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Saha P, Basak D, Biswas S, More PA, Madhavan N. Small Peptidic Ionophore for Calcium Transport. Bioconjug Chem 2022; 33:2143-2148. [DOI: 10.1021/acs.bioconjchem.2c00396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Parichita Saha
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Debajyoti Basak
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, Tamil Nadu 600036, India
| | - Sayantan Biswas
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Priyanka A. More
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Nandita Madhavan
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
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3
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Xue M, Mackin C, Weng WH, Zhu J, Luo Y, Luo SXL, Lu AY, Hempel M, McVay E, Kong J, Palacios T. Integrated biosensor platform based on graphene transistor arrays for real-time high-accuracy ion sensing. Nat Commun 2022; 13:5064. [PMID: 36030295 PMCID: PMC9420106 DOI: 10.1038/s41467-022-32749-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 08/12/2022] [Indexed: 12/01/2022] Open
Abstract
Two-dimensional materials such as graphene have shown great promise as biosensors, but suffer from large device-to-device variation due to non-uniform material synthesis and device fabrication technologies. Here, we develop a robust bioelectronic sensing platform composed of more than 200 integrated sensing units, custom-built high-speed readout electronics, and machine learning inference that overcomes these challenges to achieve rapid, portable, and reliable measurements. The platform demonstrates reconfigurable multi-ion electrolyte sensing capability and provides highly sensitive, reversible, and real-time response for potassium, sodium, and calcium ions in complex solutions despite variations in device performance. A calibration method leveraging the sensor redundancy and device-to-device variation is also proposed, while a machine learning model trained with multi-dimensional information collected through the multiplexed sensor array is used to enhance the sensing system’s functionality and accuracy in ion classification. The potential of 2D materials for biosensing applications is often limited by large device-to-device variation. Here, the authors report a calibration method and a machine learning approach leveraging the redundancy of a sensing platform based on 256 integrated graphene transistors to enhance the system accuracy in real-time ion classification.
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Affiliation(s)
- Mantian Xue
- Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | | | - Wei-Hung Weng
- Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jiadi Zhu
- Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yiyue Luo
- Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Shao-Xiong Lennon Luo
- Department of Chemistry and Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ang-Yu Lu
- Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Marek Hempel
- Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Elaine McVay
- Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jing Kong
- Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Tomás Palacios
- Department of Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
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4
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Liu Y, Liu Z, Zhao F, Tian Y. Long-Term Tracking and Dynamically Quantifying of Reversible Changes of Extracellular Ca 2+ in Multiple Brain Regions of Freely Moving Animals. Angew Chem Int Ed Engl 2021; 60:14429-14437. [PMID: 33797152 DOI: 10.1002/anie.202102833] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Indexed: 11/11/2022]
Abstract
Understanding physiological and pathological processes in the brain requires tracking the reversible changes in chemical signals with long-term stability. We developed a new anti-biofouling microfiber array to real-time quantify extracellular Ca2+ concentrations together with neuron activity across many regions in the mammalian brain for 60 days, in which the signal degradation was < ca. 8 %. The microarray with high tempo-spatial resolution (ca. 10 μm, ca. 1.3 s) was implanted into 7 brain regions of free-moving mice to monitor reversible changes of extracellular Ca2+ upon ischemia-reperfusion processes. The changing sequence and rate of Ca2+ in 7 brain regions were different during the stroke. ROS scavenger could protect Ca2+ influx and neuronal activity after stroke, suggesting the significant influence of ROS on Ca2+ overload and neuron death. We demonstrated this microarray is a versatile tool for investigating brain dynamic during pathological processes and drug treatment.
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Affiliation(s)
- Yuandong Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai, 200241, China
| | - Zhichao Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai, 200241, China
| | - Fan Zhao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai, 200241, China
| | - Yang Tian
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai, 200241, China
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5
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Liu Y, Liu Z, Zhao F, Tian Y. Long‐Term Tracking and Dynamically Quantifying of Reversible Changes of Extracellular Ca
2+
in Multiple Brain Regions of Freely Moving Animals. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102833] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Yuandong Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular Engineering East China Normal University Dongchuan Road 500 Shanghai 200241 China
| | - Zhichao Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular Engineering East China Normal University Dongchuan Road 500 Shanghai 200241 China
| | - Fan Zhao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular Engineering East China Normal University Dongchuan Road 500 Shanghai 200241 China
| | - Yang Tian
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular Engineering East China Normal University Dongchuan Road 500 Shanghai 200241 China
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6
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The Regulation of Non-Specific Membrane Permeability Transition in Yeast Mitochondria under Oxidative Stress. MICROBIOLOGY RESEARCH 2021. [DOI: 10.3390/microbiolres12020029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In this study, the mechanism of non-specific membrane permeability (yPTP) in the Endomyces magnusii yeast mitochondria under oxidative stress due to blocking the key antioxidant enzymes has been investigated. We used monitoring the membrane potential at the cellular (potential-dependent staining) and mitochondrial levels and mitochondria ultra-structural images with transmission electron microscopy (TEM) to demonstrate the mitochondrial permeability transition induction due to the pore opening. Analysis of the yPTP opening upon respiring different substrates showed that NAD(P)H completely blocked the development of the yPTP. The yPTP opening was inhibited by 5–20 mM Pi, 5 mM Mg2+, adenine nucleotides (AN), 5 mM GSH, the inhibitor of the Pi transporter (PiC), 100 μM mersalyl, the blockers of the adenine nucleotide transporter (ANT) carboxyatractyloside (CATR), and bongkrekic acid (BA). We concluded that the non-specific membrane permeability pore opens in the E. magnusii mitochondria under oxidative stress, and the ANT and PiC are involved in its formation. The crucial role of the Ca2+ ions in the process has not been confirmed. We showed that the Ca2+ ions affected the yPTP both with and without the Ca2+ ionophore ETH129 application insignificantly. This phenomenon in the E. magnusii yeast unites both mitochondrial unselective channel (ScMUC) features in the Saccharomyces cerevisiae mitochondria and the classical membrane pore in the mammalian ones (mPTP).
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Soybaş Z, Şimşek S, Erol FMB, Erdoğan UÇ, Şimşek EN, Şahin B, Marçalı M, Aydoğdu B, Elbüken Ç, Melik R. Real-Time In Vivo Control of Neural Membrane Potential by Electro-Ionic Modulation. iScience 2019; 17:347-358. [PMID: 31326701 PMCID: PMC6651852 DOI: 10.1016/j.isci.2019.06.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/11/2019] [Accepted: 06/28/2019] [Indexed: 11/11/2022] Open
Abstract
Theoretically, by controlling neural membrane potential (Vm) in vivo, motion, sensation, and behavior can be controlled. Until now, there was no available technique that can increase or decrease ion concentration in vivo in real time to change neural membrane potential. We introduce a method that we coin electro-ionic modulation (EIM), wherein ionic concentration around a nerve can be controlled in real time and in vivo. We used an interface to regulate the Ca2+ ion concentration around the sciatic nerve of a frog and thus achieved stimulation and blocking with higher resolution and lower current compared with electrical stimulation. As EIM achieves higher controllability of Vm, it has potential to replace conventional methods used for the treatment of neurological disorders and may bring a new perspective to neuromodulation techniques. EIM regulates extracellular ion concentration in vivo in real time EIM stimulates or blocks the nerve via Ca2+ ion depletion or enhancement EIM achieves selective stimulation or blocking of large or small axons EIM is the most superior neuromodulation method for real-life applications
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Affiliation(s)
- Zafer Soybaş
- Department of Electrical and Electronics Engineering, TOBB University of Economics & Technology, Ankara 06510, Turkey
| | - Sefa Şimşek
- Department of Electrical and Electronics Engineering, TOBB University of Economics & Technology, Ankara 06510, Turkey
| | - F M Betül Erol
- Faculty of Medicine, Hacettepe University, Ankara 06100, Turkey
| | - U Çiya Erdoğan
- Department of Electrical and Electronics Engineering, TOBB University of Economics & Technology, Ankara 06510, Turkey
| | - Esra N Şimşek
- Department of Electrical and Electronics Engineering, TOBB University of Economics & Technology, Ankara 06510, Turkey
| | - Büşra Şahin
- Department of Electrical and Electronics Engineering, TOBB University of Economics & Technology, Ankara 06510, Turkey
| | - Merve Marçalı
- Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
| | - Bahattin Aydoğdu
- Department of Pediatric Surgery, Dicle University Medical Faculty, Diyarbakır 21280, Turkey
| | - Çağlar Elbüken
- Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center (UNAM), Bilkent University, Ankara 06800, Turkey
| | - Rohat Melik
- Department of Electrical and Electronics Engineering, TOBB University of Economics & Technology, Ankara 06510, Turkey.
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Parks RJ, Menazza S, Holmström KM, Amanakis G, Fergusson M, Ma H, Aponte AM, Bernardi P, Finkel T, Murphy E. Cyclophilin D-mediated regulation of the permeability transition pore is altered in mice lacking the mitochondrial calcium uniporter. Cardiovasc Res 2019; 115:385-394. [PMID: 30165576 PMCID: PMC6657279 DOI: 10.1093/cvr/cvy218] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 07/05/2018] [Accepted: 08/22/2018] [Indexed: 12/14/2022] Open
Abstract
Aims Knockout (KO) of the mitochondrial Ca2+ uniporter (MCU) in mice abrogates mitochondrial Ca2+ uptake and permeability transition pore (PTP) opening. However, hearts from global MCU-KO mice are not protected from ischaemic injury. We aimed to investigate whether adaptive alterations occur in cell death signalling pathways in the hearts of global MCU-KO mice. Methods and results First, we examined whether cell death may occur via an upregulation in necroptosis in MCU-KO mice. However, our results show that neither RIP1 inhibition nor RIP3 knockout afford protection against ischaemia-reperfusion injury in MCU-KO as in wildtype (WT) hearts, indicating that the lack of protection cannot be explained by upregulation of necroptosis. Instead, we have identified alterations in cyclophilin D (CypD) signalling in MCU-KO hearts. In the presence of a calcium ionophore, MCU-KO mitochondria take up calcium and do undergo PTP opening. Furthermore, PTP opening in MCU-KO mitochondria has a lower calcium retention capacity (CRC), suggesting that the calcium sensitivity of PTP is higher. Phosphoproteomics identified an increase in phosphorylation of CypD-S42 in MCU-KO. We investigated the interaction of CypD with the putative PTP component ATP synthase and identified an approximately 50% increase in this interaction in MCU-KO cardiac mitochondria. Mutation of the novel CypD phosphorylation site S42 to a phosphomimic reduced CRC, increased CypD-ATP synthase interaction by approximately 50%, and increased cell death in comparison to a phospho-resistant mutant. Conclusion Taken together these data suggest that MCU-KO mitochondria exhibit an increase in phosphorylation of CypD-S42 which decreases PTP calcium sensitivity thus allowing activation of PTP in the absence of an MCU-mediated increase in matrix calcium.
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Affiliation(s)
- Randi J Parks
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive Bethesda, MD, USA
| | - Sara Menazza
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive Bethesda, MD, USA
| | | | - Georgios Amanakis
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive Bethesda, MD, USA
| | - Maria Fergusson
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive Bethesda, MD, USA
| | - Hanley Ma
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive Bethesda, MD, USA
| | | | - Paolo Bernardi
- Department of Biomedical Sciences, University of Padova, Italy
| | - Toren Finkel
- Center for Molecular Medicine, NHLBI, NIH, Bethesda, MD, USA
| | - Elizabeth Murphy
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive Bethesda, MD, USA
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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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Ca 2+ ionophores are not suitable for inducing mPTP opening in murine isolated adult cardiac myocytes. Sci Rep 2017; 7:4283. [PMID: 28655872 PMCID: PMC5487341 DOI: 10.1038/s41598-017-04618-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/17/2017] [Indexed: 11/08/2022] Open
Abstract
Opening of the mitochondrial permeability transition pore (mPTP) plays a major role in cell death during cardiac ischaemia-reperfusion. Adult isolated rodent cardiomyocytes are valuable cells to study the effect of drugs targeting mPTP. This study investigated whether the use of Ca2+ ionophores (A23187, ionomycin and ETH129) represent a reliable model to study inhibition of mPTP opening in cardiomyocytes. We monitored mPTP opening using the calcein/cobalt fluorescence technique in adult rat and wild type or cyclophilin D (CypD) knock-out mice cardiomyocytes. Cells were either treated with Ca2+ ionophores or subjected to hypoxia followed by reoxygenation. The ionophores induced mPTP-dependent swelling in isolated mitochondria. A23187, but not ionomycin, induced a decrease in calcein fluorescence. This loss could not be inhibited by CypD deletion and was explained by a direct interaction between A23187 and cobalt. ETH129 caused calcein loss, mitochondrial depolarization and cell death but CypD deletion did not alleviate these effects. In the hypoxia-reoxygenation model, CypD deletion delayed both mPTP opening and cell death occurring at the time of reoxygenation. Thus, Ca2+ ionophores are not suitable to induce CypD-dependent mPTP opening in adult murine cardiomyocytes. Hypoxia-reoxygenation conditions appear therefore as the most reliable model to investigate mPTP opening in these cells.
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Differential effects of non-steroidal anti-inflammatory drugs on mitochondrial dysfunction during oxidative stress. Arch Biochem Biophys 2009; 490:1-8. [DOI: 10.1016/j.abb.2009.07.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Mefloquine-induced disruption of calcium homeostasis in mammalian cells is similar to that induced by ionomycin. Antimicrob Agents Chemother 2007; 52:684-93. [PMID: 17999964 DOI: 10.1128/aac.00874-07] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In previous studies, we have shown that mefloquine disrupts calcium homeostasis in neurons by depletion of endoplasmic reticulum (ER) stores, followed by an influx of external calcium across the plasma membrane. In this study, we explore two hypotheses concerning the mechanism(s) of action of mefloquine. First, we investigated the possibility that mefloquine activates non-N-methyl-d-aspartic acid receptors and the inositol phosphate 3 (IP3) signaling cascade leading to ER calcium release. Second, we compared the disruptive effects of mefloquine on calcium homeostasis to those of ionomycin in neuronal and nonneuronal cells. Ionomycin is known to discharge the ER calcium store (through an undefined mechanism), which induces capacitative calcium entry (CCE). In radioligand binding assays, mefloquine showed no affinity for the known binding sites of several glutamate receptor subtypes. The pattern of neuroprotection induced by a panel of glutamate receptor antagonists was dissimilar to that of mefloquine. Both mefloquine and ionomycin exhibited dose-related and qualitatively similar disruptions of calcium homeostasis in both neurons and macrophages. The influx of external calcium was blocked by the inhibitors of CCE in a dose-related fashion. Both mefloquine and ionomycin upregulated the IP3 pathway in a manner that we interpret to be secondary to CCE. Collectively, these data suggest that mefloquine does not activate glutamate receptors and that it disrupts calcium homeostasis in mammalian cells in a manner similar to that of ionomycin.
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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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Xia X, Wang G, Peng Y, Tu MG, Jen J, Fang H. The Endogenous CXXC Motif Governs the Cadmium Sensitivity of the Renal Na+/Glucose Co-Transporter. J Am Soc Nephrol 2005; 16:1257-65. [PMID: 15829715 DOI: 10.1681/asn.2004070594] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Cadmium (Cd2+) poisoning causes severe renal disorders manifested by defects in reabsorptive transport of various compounds. It is reported here that the renal brush-border membrane Na+/glucose co-transporter-1 (SGLT1) is a molecular target for Cd2+ toxicity. In micromolar concentrations, Cd2+ acted as a noncompetitive, partial inhibitor of methyl-D-glucopyranoside uptake in vesicles from COS-7 cells transiently expressing SGLT1. In contrast, only a modest effect in the closely related Na+/myo-inositol co-transporter-1 (SMIT1) was observed. The factor responsible for this difference was the CXXC motif (X can be any residue) at the cytoplasmic end of the eighth transmembrane segment (TM8) of SGLT1. Thus, a mutational transfer of this motif conveyed Cd2+ sensitivity to SMIT1. Moreover, mimicking the inhibitory effect of Cd2+, the biarsenical molecule FlAsH-EDT2 strongly inhibited the SGLT1 that had an engineered tetracysteine motif at the cytoplasmic end of TM8. The experiments also showed that covalent binding of the sulfhydryl reactive biotin-PEO-maleimide to the SGLT1 wild type but not to the mutant lacking the CXXC motif was suppressed by Cd2+. Taken together, these results suggest that in SGLT1, Cd2+ binding to the CXXC motif induces conformational changes that cause a partial inhibition of d-glucose transport.
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Affiliation(s)
- Xiaobing Xia
- Beijing 302 Hospital, Beijing, People's Republic of China 100039.
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15
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Kang TM, Hilgemann DW. Multiple transport modes of the cardiac Na+/Ca2+ exchanger. Nature 2004; 427:544-8. [PMID: 14765196 DOI: 10.1038/nature02271] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2003] [Accepted: 12/05/2003] [Indexed: 11/08/2022]
Abstract
The cardiac Na+/Ca2+ exchanger (NCX1; ref. 2) is a bi-directional Ca2+ transporter that contributes to the electrical activity of the heart. When, and if, Ca2+ is exported or imported depends on the Na+/Ca2+ exchange ratio. Whereas a ratio of 3:1 (Na+:Ca2+) has been indicated by Ca2+ flux equilibrium studies, a ratio closer to 4:1 has been indicated by exchange current reversal potentials. Here we show, using an ion-selective electrode technique to quantify ion fluxes in giant patches, that ion flux ratios are approximately 3.2 for maximal transport in either direction. With Na+ and Ca2+ on both sides of the membrane, net current and Ca2+ flux can reverse at different membrane potentials, and inward current can be generated in the absence of cytoplasmic Ca2+, but not Na+. We propose that NCX1 can transport not only 1 Ca2+ or 3 Na+ ions, but also 1 Ca2+ with 1 Na+ ion at a low rate. Therefore, in addition to the major 3:1 transport mode, import of 1 Na+ with 1 Ca2+ defines a Na+-conducting mode that exports 1 Ca2+, and an electroneutral Ca2+ influx mode that exports 3 Na+. The two minor transport modes can potentially determine resting free Ca2+ and background inward current in heart.
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Affiliation(s)
- Tong Mook Kang
- Department of Physiology, Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea
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Jung DW, Bradshaw PC, Litsky M, Pfeiffer DR. Ca2+ transport in mitochondria from yeast expressing recombinant aequorin. Anal Biochem 2004; 324:258-68. [PMID: 14690690 DOI: 10.1016/j.ab.2003.10.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We have expressed aequorin in mitochondria of the yeast Saccharomyces cerevisiae and characterized the resulting strain with respect to mitochondrial Ca(2+) transport in vivo and in vitro. When intact cells are suspended in water containing 1.4 mM ethanol and 14 mM CaCl(2), the matrix free Ca(2+) concentration is 200 nM, similar to the values expected in cytoplasm. Addition of ionophore ETH 129 allows an active accumulation of Ca(2+) and promptly increases the value to 1.2 microM. Elevated Ca(2+) concentrations are maintained for periods of 6 min or longer under these conditions. Isolated yeast mitochondria oxidizing ethanol also accumulate Ca(2+) when ETH 129 is present, but the cation is not retained depending on the medium conditions. This finding confirms the presence of a Ca(2+) release mechanism that requires free fatty acids as previously described [P.C. Bradshaw et al. (2001) J. Biol. Chem. 276, 40502-40509]. When a respiratory substrate is not present, Ca(2+) enters and leaves yeast mitochondria slowly, at a specific activity near 0.2 nmol/min/mg protein. Transport under these conditions equilibrates the internal and external concentrations of Ca(2+) and is not affected by ruthenium red, uncouplers, or ionophores that perturb transmembrane gradients of charge and pH. This activity displays sigmoid kinetics and a K(1/2) value for Ca(2+) that is near to 900 nM, in the absence of ethanol or when it is present. It is furthermore shown that the activity coefficient of Ca(2+) in yeast mitochondria is a function of the matrix Ca(2+) content and is substantially larger than that in mammalian mitochondria. Characteristics of the aequorin-expressing strain appear suitable for its use in expression-based methods directed at cloning Ca(2+) transporters from mammalian mitochondria and for further examining the interrelationships between mitochondrial and cytoplasmic Ca(2+) in yeast.
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Affiliation(s)
- Dennis W Jung
- Department of Molecular and Cellular Biochemistry, The Ohio State University Medical Center, Columbus, OH 43210, USA
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Hamidinia SA, Shimelis OI, Tan B, Erdahl WL, Chapman CJ, Renkes GD, Taylor RW, Pfeiffer DR. Monensin mediates a rapid and selective transport of Pb(2+). Possible application of monensin for the treatment of Pb(2+) intoxication. J Biol Chem 2002; 277:38111-20. [PMID: 12080080 DOI: 10.1074/jbc.m205590200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The carboxylic acid ionophore monensin, known as an electroneutral Na(+) ionophore, an anticoccidial agent, and a growth-promoting feed additive in agriculture, is shown to be highly efficient as an ionophore for Pb(2+) and to be highly selective for Pb(2+) compared with other divalent cations. Monensin transports Pb(2+) by an electroneutral mechanism in which the complex PbMonOH is the transporting species. Electrogenic transport via the species PbMon(+) may also be possible. Monensin catalyzed Pb(2+) transport is little affected by Ca(2+), Mg(2+), or K(+) concentrations that are encountered in living systems. Na(+) is inhibitory, but its effectiveness at 100 mm does not exceed approximately 50%. The poor activity of monensin as an ionophore for divalent cations other than Pb(2+) is consistent with the pattern of complex formation constants observed in the mixed solvent 80% methanol/water. This pattern also explains why Ca(2+), Mg(2+), and K(+) are ineffective as inhibitors of Pb(2+) transport, but it does not fully explain the actions of Na(+), where kinetic features of the transport mechanism may also be important. When given to rats at 100 ppm in feed together with Pb(2+) at 100 ppm in drinking water, monensin reduces Pb accumulation in several organs and tissues. It also accelerates the excretion of Pb that was accumulated previously and produces this effect without depleting the organs of zinc or copper. Monensin, used alone or in combination with other agents, may be useful for the treatment of Pb intoxication.
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Affiliation(s)
- Shawn A Hamidinia
- Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, Ohio 43210, USA
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