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Maraslioglu-Sperber A, Pizzi E, Fisch JO, Kattler K, Ritter T, Friauf E. Molecular and functional profiling of cell diversity and identity in the lateral superior olive, an auditory brainstem center with ascending and descending projections. Front Cell Neurosci 2024; 18:1354520. [PMID: 38846638 PMCID: PMC11153811 DOI: 10.3389/fncel.2024.1354520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/15/2024] [Indexed: 06/09/2024] Open
Abstract
The lateral superior olive (LSO), a prominent integration center in the auditory brainstem, contains a remarkably heterogeneous population of neurons. Ascending neurons, predominantly principal neurons (pLSOs), process interaural level differences for sound localization. Descending neurons (lateral olivocochlear neurons, LOCs) provide feedback into the cochlea and are thought to protect against acoustic overload. The molecular determinants of the neuronal diversity in the LSO are largely unknown. Here, we used patch-seq analysis in mice at postnatal days P10-12 to classify developing LSO neurons according to their functional and molecular profiles. Across the entire sample (n = 86 neurons), genes involved in ATP synthesis were particularly highly expressed, confirming the energy expenditure of auditory neurons. Two clusters were identified, pLSOs and LOCs. They were distinguished by 353 differentially expressed genes (DEGs), most of which were novel for the LSO. Electrophysiological analysis confirmed the transcriptomic clustering. We focused on genes affecting neuronal input-output properties and validated some of them by immunohistochemistry, electrophysiology, and pharmacology. These genes encode proteins such as osteopontin, Kv11.3, and Kvβ3 (pLSO-specific), calcitonin-gene-related peptide (LOC-specific), or Kv7.2 and Kv7.3 (no DEGs). We identified 12 "Super DEGs" and 12 genes showing "Cluster similarity." Collectively, we provide fundamental and comprehensive insights into the molecular composition of individual ascending and descending neurons in the juvenile auditory brainstem and how this may relate to their specific functions, including developmental aspects.
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Affiliation(s)
- Ayse Maraslioglu-Sperber
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Erika Pizzi
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Jonas O. Fisch
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Kathrin Kattler
- Genetics/Epigenetics Group, Department of Biological Sciences, Saarland University, Saarbrücken, Germany
| | - Tamara Ritter
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Eckhard Friauf
- Animal Physiology Group, Department of Biology, University of Kaiserslautern-Landau, Kaiserslautern, Germany
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2
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Chan D, Cromar GL, Taj B, Parkinson J. Cell4D: a general purpose spatial stochastic simulator for cellular pathways. BMC Bioinformatics 2024; 25:121. [PMID: 38515063 PMCID: PMC10956314 DOI: 10.1186/s12859-024-05739-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 03/11/2024] [Indexed: 03/23/2024] Open
Abstract
BACKGROUND With the generation of vast compendia of biological datasets, the challenge is how best to interpret 'omics data alongside biochemical and other small-scale experiments to gain meaningful biological insights. Key to this challenge are computational methods that enable domain-users to generate novel hypotheses that can be used to guide future experiments. Of particular interest are flexible modeling platforms, capable of simulating a diverse range of biological systems with low barriers of adoption to those with limited computational expertise. RESULTS We introduce Cell4D, a spatial-temporal modeling platform combining a robust simulation engine with integrated graphics visualization, a model design editor, and an underlying XML data model capable of capturing a variety of cellular functions. Cell4D provides an interactive visualization mode, allowing intuitive feedback on model behavior and exploration of novel hypotheses, together with a non-graphics mode, compatible with high performance cloud compute solutions, to facilitate generation of statistical data. To demonstrate the flexibility and effectiveness of Cell4D, we investigate the dynamics of CEACAM1 localization in T-cell activation. We confirm the importance of Ca2+ microdomains in activating calmodulin and highlight a key role of activated calmodulin on the surface expression of CEACAM1. We further show how lymphocyte-specific protein tyrosine kinase can help regulate this cell surface expression and exploit spatial modeling features of Cell4D to test the hypothesis that lipid rafts regulate clustering of CEACAM1 to promote trans-binding to neighbouring cells. CONCLUSIONS Through demonstrating its ability to test and generate hypotheses, Cell4D represents an effective tool to help integrate knowledge across diverse, large and small-scale datasets.
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Affiliation(s)
- Donny Chan
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, M5S 1A8, Canada
| | - Graham L Cromar
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, M5G 0A4, Canada
| | - Billy Taj
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, M5G 0A4, Canada
| | - John Parkinson
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, M5G 0A4, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, M5S 1A8, Canada.
- Department of Biochemistry, University of Toronto, Toronto, M5S 1A8, Canada.
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3
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Iacobucci GJ, Popescu GK. Calcium- and calmodulin-dependent inhibition of NMDA receptor currents. Biophys J 2024; 123:277-293. [PMID: 38140727 PMCID: PMC10870176 DOI: 10.1016/j.bpj.2023.12.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/05/2023] [Accepted: 12/19/2023] [Indexed: 12/24/2023] Open
Abstract
Calcium ions (Ca2+) reduce NMDA receptor currents through several distinct mechanisms. Among these, calmodulin (CaM)-dependent inhibition (CDI) accomplishes rapid, reversible, and incomplete reduction of the NMDA receptor currents in response to elevations in intracellular Ca2+. Quantitative and mechanistic descriptions of CDI of NMDA receptor-mediated signals have been marred by variability originating, in part, from differences in the conditions and metrics used to evaluate this process across laboratories. Recent ratiometric approaches to measure the magnitude and kinetics of NMDA receptor CDI have facilitated rapid insights into this phenomenon. Notably, the kinetics and magnitude of NMDA receptor CDI depend on the degree of saturation of its CaM binding sites, which represent the bona fide calcium sensor for this type of inhibition, the kinetics and magnitude of the Ca2+ signal, which depends on the biophysical properties of the NMDA receptor or of adjacent Ca2+ sources, and on the relative distribution of Ca2+ sources and CaM molecules. Given that all these factors vary widely during development, across cell types, and with physiological and pathological states, it is important to understand how NMDA receptor CDI develops and how it contributes to signaling in the central nervous system. Here, we review briefly these recent advances and highlight remaining questions about the structural and kinetic mechanisms of NMDA receptor CDI. Given that pathologies can arise from several sources, including mutations in the NMDA receptor and in CaM, understanding how CaM responds to intracellular Ca2+ signals to initiate conformational changes in NMDA receptors, and mapping the structural domains responsible will help to envision novel therapeutic strategies to neuropsychiatric diseases, which presently have limited available treatments.
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Affiliation(s)
- Gary J Iacobucci
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, SUNY, Buffalo, New York
| | - Gabriela K Popescu
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, SUNY, Buffalo, New York.
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4
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Anderson MC, Levy AD, Dharmasri PA, Metzbower SR, Blanpied TA. Trans-synaptic molecular context of NMDA receptor nanodomains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573055. [PMID: 38187545 PMCID: PMC10769418 DOI: 10.1101/2023.12.22.573055] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Tight coordination of the spatial relationships between protein complexes is required for cellular function. In neuronal synapses, many proteins responsible for neurotransmission organize into subsynaptic nanoclusters whose trans-cellular alignment modulates synaptic signal propagation. However, the spatial relationships between these proteins and NMDA receptors (NMDARs), which are required for learning and memory, remain undefined. Here, we mapped the relationship of key NMDAR subunits to reference proteins in the active zone and postsynaptic density using multiplexed super-resolution DNA-PAINT microscopy. GluN2A and GluN2B subunits formed nanoclusters with diverse configurations that, surprisingly, were not localized near presynaptic vesicle release sites marked by Munc13-1. However, a subset of presynaptic sites was configured to maintain NMDAR activation: these were internally denser, aligned with abundant PSD-95, and associated closely with specific NMDAR nanodomains. This work reveals a new principle regulating NMDAR signaling and suggests that synaptic functional architecture depends on assembly of multiprotein nanodomains whose interior construction is conditional on trans-cellular relationships.
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Affiliation(s)
- Michael C Anderson
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Aaron D Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Poorna A Dharmasri
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Current address: Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sarah R Metzbower
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Current address: Nikon Instruments Inc, Melville, NY, USA
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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Jędrzejewska-Szmek J, Dorman DB, Blackwell KT. Making time and space for calcium control of neuron activity. Curr Opin Neurobiol 2023; 83:102804. [PMID: 37913687 PMCID: PMC10842147 DOI: 10.1016/j.conb.2023.102804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 11/03/2023]
Abstract
Calcium directly controls or indirectly regulates numerous functions that are critical for neuronal network activity. Intracellular calcium concentration is tightly regulated by numerous molecular mechanisms because spatial domains and temporal dynamics (not just peak amplitude) are critical for calcium control of synaptic plasticity and ion channel activation, which in turn determine neuron spiking activity. The computational models investigating calcium control are valuable because experiments achieving high spatial and temporal resolution simultaneously are technically unfeasible. Simulations of calcium nanodomains reveal that specific calcium sources can couple to specific calcium targets, providing a mechanism to determine the direction of synaptic plasticity. Cooperativity of calcium domains opposes specificity, suggesting that the dendritic branch might be the preferred computational unit of the neuron.
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Affiliation(s)
- Joanna Jędrzejewska-Szmek
- Laboratory of Neuroinformatics, Nencki Institute of Experimental Biology of Polish Academy of Science, 3 Pasteur Street, Warsaw, 02-093, Poland.
| | - Daniel B Dorman
- Department of Biomedical Engineering, Johns Hopkins University, 3400 N. Charles St., Baltimore, 21218, MD, USA
| | - Kim T Blackwell
- Bioengineering Department and Interdisciplinary Program in Neuroscience, George Mason University, 4400 University Drive, Fairfax, 22031, VA, USA
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Jin Z, Lakshmanan A, Zhang R, Tran TA, Rabut C, Dutka P, Duan M, Hurt RC, Malounda D, Yao Y, Shapiro MG. Ultrasonic reporters of calcium for deep tissue imaging of cellular signals. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.09.566364. [PMID: 37986929 PMCID: PMC10659314 DOI: 10.1101/2023.11.09.566364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Calcium imaging has enabled major biological discoveries. However, the scattering of light by tissue limits the use of standard fluorescent calcium indicators in living animals. To address this limitation, we introduce the first genetically encoded ultrasonic reporter of calcium (URoC). Based on a unique class of air-filled protein nanostructures called gas vesicles, we engineered URoC to produce elevated nonlinear ultrasound signal upon binding to calcium ions. With URoC expressed in mammalian cells, we demonstrate noninvasive ultrasound imaging of calcium signaling in vivo during drug-induced receptor activation. URoC brings the depth and resolution advantages of ultrasound to the in vivo imaging of dynamic cellular function and paves the way for acoustic biosensing of a broader variety of biological signals.
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7
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Satarić MV, Nemeš T. On the role of calcium diffusion and its rapid buffering in intraflagellar signaling. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:705-720. [PMID: 37851099 DOI: 10.1007/s00249-023-01685-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 09/13/2023] [Accepted: 09/23/2023] [Indexed: 10/19/2023]
Abstract
We have considered the realistic mechanism of rapid Ca2+ (calcium ion) buffering within the wave of calcium ions progressing along the flagellar axoneme. This buffering is an essential part of the Ca2+ signaling pathway aimed at controlling the bending dynamics of flagella. It is primarily achieved by the mobile region of calmodulin molecules and by stationary calaxin, as well as by the part of calmodulin bound to calcium/calmodulin-dependent kinase II and kinase C. We derived and elaborated a model of Ca2+ diffusion within a signaling wave in the presence of these molecules which rapidly buffer Ca2+. This approach has led to a single nonlinear transport equation for the Ca2+ wave that contains the effects brought about by both as necessary buffers for signaling. The presence of mobile buffer calmodulin gives rise to a transport equation that is not strictly diffusive but also exhibits a sink-like effect. We solved straightforwardly the final transport equation in an analytical framework and obtained the implied function of calcium concentration. The effective diffusion coefficient depends on local Ca2+ concentration. It is plausible that these buffers' presence can impact Ca2+ wave speed and shape, which are essential for decoding Ca2+ signaling in flagella. We present the solution of the transport equation for a few specified cases with physiologically reasonable sets of parameters involved.
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Affiliation(s)
- M V Satarić
- Serbian Academy of Science and Arts, Belgrade, Serbia
| | - T Nemeš
- Faculty of Technical Sciences, University of Novi Sad, Novi Sad, Serbia.
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Norman CA, Krishnakumar SS, Timofeeva Y, Volynski KE. The release of inhibition model reproduces kinetics and plasticity of neurotransmitter release in central synapses. Commun Biol 2023; 6:1091. [PMID: 37891212 PMCID: PMC10611806 DOI: 10.1038/s42003-023-05445-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Calcium-evoked release of neurotransmitters from synaptic vesicles (SVs) is catalysed by SNARE proteins. The predominant view is that, at rest, complete assembly of SNARE complexes is inhibited ('clamped') by synaptotagmin and complexin molecules. Calcium binding by synaptotagmins releases this fusion clamp and triggers fast SV exocytosis. However, this model has not been quantitatively tested over physiological timescales. Here we describe an experimentally constrained computational modelling framework to quantitatively assess how the molecular architecture of the fusion clamp affects SV exocytosis. Our results argue that the 'release-of-inhibition' model can indeed account for fast calcium-activated SV fusion, and that dual binding of synaptotagmin-1 and synaptotagmin-7 to the same SNARE complex enables synergistic regulation of the kinetics and plasticity of neurotransmitter release. The developed framework provides a powerful and adaptable tool to link the molecular biochemistry of presynaptic proteins to physiological data and efficiently test the plausibility of calcium-activated neurotransmitter release models.
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Affiliation(s)
- Christopher A Norman
- University College London Institute of Neurology, University College London, London, WC1N 3BG, UK
- Department of Computer Science, University of Warwick, Coventry, CV4 7AL, UK
- Mathematics for Real-World Systems Centre for Doctoral Training, University of Warwick, Coventry, CV4 7AL, UK
| | - Shyam S Krishnakumar
- University College London Institute of Neurology, University College London, London, WC1N 3BG, UK.
- Department of Neurology, Yale Nanobiology Institute, Yale University School of Medicine, New Haven, CT, 06510, USA.
| | - Yulia Timofeeva
- University College London Institute of Neurology, University College London, London, WC1N 3BG, UK.
- Department of Computer Science, University of Warwick, Coventry, CV4 7AL, UK.
| | - Kirill E Volynski
- University College London Institute of Neurology, University College London, London, WC1N 3BG, UK.
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, 06510, USA.
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9
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Eisner D, Neher E, Taschenberger H, Smith G. Physiology of intracellular calcium buffering. Physiol Rev 2023; 103:2767-2845. [PMID: 37326298 DOI: 10.1152/physrev.00042.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 05/08/2023] [Accepted: 06/11/2023] [Indexed: 06/17/2023] Open
Abstract
Calcium signaling underlies much of physiology. Almost all the Ca2+ in the cytoplasm is bound to buffers, with typically only ∼1% being freely ionized at resting levels in most cells. Physiological Ca2+ buffers include small molecules and proteins, and experimentally Ca2+ indicators will also buffer calcium. The chemistry of interactions between Ca2+ and buffers determines the extent and speed of Ca2+ binding. The physiological effects of Ca2+ buffers are determined by the kinetics with which they bind Ca2+ and their mobility within the cell. The degree of buffering depends on factors such as the affinity for Ca2+, the Ca2+ concentration, and whether Ca2+ ions bind cooperatively. Buffering affects both the amplitude and time course of cytoplasmic Ca2+ signals as well as changes of Ca2+ concentration in organelles. It can also facilitate Ca2+ diffusion inside the cell. Ca2+ buffering affects synaptic transmission, muscle contraction, Ca2+ transport across epithelia, and the killing of bacteria. Saturation of buffers leads to synaptic facilitation and tetanic contraction in skeletal muscle and may play a role in inotropy in the heart. This review focuses on the link between buffer chemistry and function and how Ca2+ buffering affects normal physiology and the consequences of changes in disease. As well as summarizing what is known, we point out the many areas where further work is required.
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Affiliation(s)
- David Eisner
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Erwin Neher
- Membrane Biophysics Laboratory, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Holger Taschenberger
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Godfrey Smith
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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10
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Coronado LM, Stoute JA, Nadovich CT, Cheng J, Correa R, Chaw K, González G, Zambrano M, Gittens RA, Agrawal DK, Jemison WD, Donado Morcillo CA, Spadafora C. Microwaves can kill malaria parasites non-thermally. Front Cell Infect Microbiol 2023; 13:955134. [PMID: 36816585 PMCID: PMC9932958 DOI: 10.3389/fcimb.2023.955134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
Malaria, which infected more than 240 million people and killed around six hundred thousand only in 2021, has reclaimed territory after the SARS-CoV-2 pandemic. Together with parasite resistance and a not-yet-optimal vaccine, the need for new approaches has become critical. While earlier, limited, studies have suggested that malaria parasites are affected by electromagnetic energy, the outcomes of this affectation vary and there has not been a study that looks into the mechanism of action behind these responses. In this study, through development and implementation of custom applicators for in vitro experimentation, conditions were generated in which microwave energy (MW) killed more than 90% of the parasites, not by a thermal effect but via a MW energy-induced programmed cell death that does not seem to affect mammalian cell lines. Transmission electron microscopy points to the involvement of the haemozoin-containing food vacuole, which becomes destroyed; while several other experimental approaches demonstrate the involvement of calcium signaling pathways in the resulting effects of exposure to MW. Furthermore, parasites were protected from the effects of MW by calcium channel blockers calmodulin and phosphoinositol. The findings presented here offer a molecular insight into the elusive interactions of oscillating electromagnetic fields with P. falciparum, prove that they are not related to temperature, and present an alternative technology to combat this devastating disease.
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Affiliation(s)
- Lorena M. Coronado
- Biomedical Physics and Engineering Unit, Center of Cellular and Molecular Biology of Diseases (CBCMe), Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City, Panama,Department of Biotechnology, Acharya Nagarjuna University, Guntur, India,Biomedical Physics and Engineering (BiomedφEngine) Group, Panama City, Panama
| | - José A. Stoute
- Department of Medicine, Division of Infectious Diseases and Epidemiology, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Christopher T. Nadovich
- Electrical and Computer Engineering, Lafayette College, Easton, PA, United States,Wallace H. Coulter School of Engineering, Clarkson University, Potsdam, NY, United States
| | - Jiping Cheng
- Department of Material Science and Engineering, Pennsylvania State University, University Park, PA, United States
| | - Ricardo Correa
- Biomedical Physics and Engineering Unit, Center of Cellular and Molecular Biology of Diseases (CBCMe), Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City, Panama,Department of Biotechnology, Acharya Nagarjuna University, Guntur, India,Biomedical Physics and Engineering (BiomedφEngine) Group, Panama City, Panama
| | - Kevin Chaw
- Biomedical Physics and Engineering Unit, Center of Cellular and Molecular Biology of Diseases (CBCMe), Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City, Panama,Biomedical Physics and Engineering (BiomedφEngine) Group, Panama City, Panama,School of Technology and Engineering, Universidad Católica Santa María La Antigua, Panama City, Panama
| | - Guadalupe González
- Biomedical Physics and Engineering (BiomedφEngine) Group, Panama City, Panama,School of Electrical Engineering, Universidad Tecnológica de Panamá, Panama City, Panama
| | - Maytee Zambrano
- Biomedical Physics and Engineering (BiomedφEngine) Group, Panama City, Panama,School of Electrical Engineering, Universidad Tecnológica de Panamá, Panama City, Panama
| | - Rolando A. Gittens
- Biomedical Physics and Engineering Unit, Center of Cellular and Molecular Biology of Diseases (CBCMe), Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City, Panama,Biomedical Physics and Engineering (BiomedφEngine) Group, Panama City, Panama
| | - Dinesh K. Agrawal
- Department of Material Science and Engineering, Pennsylvania State University, University Park, PA, United States
| | - William D. Jemison
- Wallace H. Coulter School of Engineering, Clarkson University, Potsdam, NY, United States
| | - Carlos A. Donado Morcillo
- Biomedical Physics and Engineering Unit, Center of Cellular and Molecular Biology of Diseases (CBCMe), Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City, Panama,Biomedical Physics and Engineering (BiomedφEngine) Group, Panama City, Panama,School of Technology and Engineering, Universidad Católica Santa María La Antigua, Panama City, Panama
| | - Carmenza Spadafora
- Biomedical Physics and Engineering Unit, Center of Cellular and Molecular Biology of Diseases (CBCMe), Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City, Panama,Biomedical Physics and Engineering (BiomedφEngine) Group, Panama City, Panama,*Correspondence: Carmenza Spadafora,
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11
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A Modeling and Analysis Study Reveals That CaMKII in Synaptic Plasticity Is a Dominant Affecter in CaM Systems in a T286 Phosphorylation-Dependent Manner. Molecules 2022; 27:molecules27185974. [PMID: 36144710 PMCID: PMC9501549 DOI: 10.3390/molecules27185974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/18/2022] [Accepted: 08/25/2022] [Indexed: 11/17/2022] Open
Abstract
NMDAR-dependent synaptic plasticity in the hippocampus consists of two opposing forces: long-term potentiation (LTP), which strengthens synapses and long-term depression (LTD), which weakens synapses. LTP and LTD are associated with memory formation and loss, respectively. Synaptic plasticity is controlled at a molecular level by Ca2+-mediated protein signaling. Here, Ca2+ binds the protein, calmodulin (CaM), which modulates synaptic plasticity in both directions. This is because Ca2+-bound CaM activates both LTD-and LTP-inducing proteins. Understanding how CaM responds to Ca2+ signaling and how this translates into synaptic plasticity is therefore important to understanding synaptic plasticity induction. In this paper, CaM activation by Ca2+ and calmodulin binding to downstream proteins was mathematically modeled using differential equations. Simulations were monitored with and without theoretical knockouts and, global sensitivity analyses were performed to determine how Ca2+/CaM signaling occurred at various Ca2+ signals when CaM levels were limiting. At elevated stimulations, the total CaM pool rapidly bound to its protein binding targets which regulate both LTP and LTD. This was followed by CaM becoming redistributed from low-affinity to high-affinity binding targets. Specifically, CaM was redistributed away from LTD-inducing proteins to bind the high-affinity LTP-inducing protein, calmodulin-dependent kinase II (CaMKII). In this way, CaMKII acted as a dominant affecter and repressed activation of opposing CaM-binding protein targets. The model thereby showed a novel form of CaM signaling by which the two opposing pathways crosstalk indirectly. The model also found that CaMKII can repress cAMP production by repressing CaM-regulated proteins, which catalyze cAMP production. The model also found that at low Ca2+ stimulation levels, typical of LTD induction, CaM signaling was unstable and is therefore unlikely to alone be enough to induce synaptic depression. Overall, this paper demonstrates how limiting levels of CaM may be a fundamental aspect of Ca2+ regulated signaling which allows crosstalk among proteins without requiring directly interaction.
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12
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Mohanan AG, Gunasekaran S, Jacob RS, Omkumar RV. Role of Ca2+/Calmodulin-Dependent Protein Kinase Type II in Mediating Function and Dysfunction at Glutamatergic Synapses. Front Mol Neurosci 2022; 15:855752. [PMID: 35795689 PMCID: PMC9252440 DOI: 10.3389/fnmol.2022.855752] [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: 01/15/2022] [Accepted: 03/21/2022] [Indexed: 01/25/2023] Open
Abstract
Glutamatergic synapses harbor abundant amounts of the multifunctional Ca2+/calmodulin-dependent protein kinase type II (CaMKII). Both in the postsynaptic density as well as in the cytosolic compartment of postsynaptic terminals, CaMKII plays major roles. In addition to its Ca2+-stimulated kinase activity, it can also bind to a variety of membrane proteins at the synapse and thus exert spatially restricted activity. The abundance of CaMKII in glutamatergic synapse is akin to scaffolding proteins although its prominent function still appears to be that of a kinase. The multimeric structure of CaMKII also confers several functional capabilities on the enzyme. The versatility of the enzyme has prompted hypotheses proposing several roles for the enzyme such as Ca2+ signal transduction, memory molecule function and scaffolding. The article will review the multiple roles played by CaMKII in glutamatergic synapses and how they are affected in disease conditions.
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Affiliation(s)
- Archana G. Mohanan
- Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
| | - Sowmya Gunasekaran
- Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
- Research Scholar, Manipal Academy of Higher Education, Manipal, India
| | - Reena Sarah Jacob
- Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
- Research Scholar, Manipal Academy of Higher Education, Manipal, India
| | - R. V. Omkumar
- Neurobiology Division, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India
- *Correspondence: R. V. Omkumar,
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13
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Mendonça PRF, Tagliatti E, Langley H, Kotzadimitriou D, Zamora-Chimal CG, Timofeeva Y, Volynski KE. Asynchronous glutamate release is enhanced in low release efficacy synapses and dispersed across the active zone. Nat Commun 2022; 13:3497. [PMID: 35715404 PMCID: PMC9206079 DOI: 10.1038/s41467-022-31070-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 05/31/2022] [Indexed: 11/09/2022] Open
Abstract
The balance between fast synchronous and delayed asynchronous release of neurotransmitters has a major role in defining computational properties of neuronal synapses and regulation of neuronal network activity. However, how it is tuned at the single synapse level remains poorly understood. Here, using the fluorescent glutamate sensor SF-iGluSnFR, we image quantal vesicular release in tens to hundreds of individual synaptic outputs from single pyramidal cells with 4 millisecond temporal and 75 nm spatial resolution. We find that the ratio between synchronous and asynchronous synaptic vesicle exocytosis varies extensively among synapses supplied by the same axon, and that the synchronicity of release is reduced at low release probability synapses. We further demonstrate that asynchronous exocytosis sites are more widely distributed within the release area than synchronous sites. Together, our results reveal a universal relationship between the two major functional properties of synapses - the timing and the overall efficacy of neurotransmitter release.
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Affiliation(s)
- Philipe R F Mendonça
- University College London Institute of Neurology, London, UK. .,Department of Physiology and Biophysics, Federal University of Minas Gerais, Gerais, Brazil.
| | - Erica Tagliatti
- University College London Institute of Neurology, London, UK
| | - Helen Langley
- University College London Institute of Neurology, London, UK
| | | | | | - Yulia Timofeeva
- University College London Institute of Neurology, London, UK. .,Department of Computer Science, University of Warwick, Coventry, UK.
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14
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Guo L, Xu B, Zhao H, Guo Y, Jiang Y. Calmodulin Activity Affects the Function of the Odorant Receptor AcerOr2 in Honeybees. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.848150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Bees rely on their sensitive olfactory system to perform foraging activities in the surrounding environment. This ability is associated with the existence of olfactory receptors (ORs). In this study, we identified the AcerOr2 (ortholog to the Orco) protein in Apis cerana cerana, which contains a conserved, putative calmodulin (CaM)-binding site (CBS) indicating that CaM is involved in its function. We used immunofluorescence, Western blot, and Ca2 + imaging to monitor changes in the expression and activation of the signaling pathway associated with Ca2 + and Ca2 +/CaM-dependent protein kinase II (CaMKII) in Sf9 cells heterologously expressing AcerOr2 and a CaM-binding mutant. We used the synthetic Orco agonist VUAA1 to stimulate the cells or the antagonist W7 to inhibit CaM activity. The AcerOr2 CaM-binding mutant has a point mutation in the putative CBS (K331N). When heterologously expressed in Sf9 cells, the mutant should have less CaM activity. When the cells expressing AcerOr2 were treated with W7, the Ca2 + response of AceOr2 was similar to that of the mutant stimulated by VUAA1, and the expression of the CaM, CaMKII, and p-CaMKII has similar effects. Our results suggest that CaM activity affects the function of AceOr2 in vitro and can be used to further study the interaction between the AcerOr2 and calcium/CaM signaling pathway in the pollen collection behavior of bees.
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15
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Konietzny A, Grendel J, Kadek A, Bucher M, Han Y, Hertrich N, Dekkers DHW, Demmers JAA, Grünewald K, Uetrecht C, Mikhaylova M. Caldendrin and myosin V regulate synaptic spine apparatus localization via ER stabilization in dendritic spines. EMBO J 2022; 41:e106523. [PMID: 34935159 PMCID: PMC8844991 DOI: 10.15252/embj.2020106523] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/08/2021] [Accepted: 11/19/2021] [Indexed: 11/21/2022] Open
Abstract
Excitatory synapses of principal hippocampal neurons are frequently located on dendritic spines. The dynamic strengthening or weakening of individual inputs results in structural and molecular diversity of dendritic spines. Active spines with large calcium ion (Ca2+ ) transients are frequently invaded by a single protrusion from the endoplasmic reticulum (ER), which is dynamically transported into spines via the actin-based motor myosin V. An increase in synaptic strength correlates with stable anchoring of the ER, followed by the formation of an organelle referred to as the spine apparatus. Here, we show that myosin V binds the Ca2+ sensor caldendrin, a brain-specific homolog of the well-known myosin V interactor calmodulin. While calmodulin is an essential activator of myosin V motor function, we found that caldendrin acts as an inhibitor of processive myosin V movement. In mouse and rat hippocampal neurons, caldendrin regulates spine apparatus localization to a subset of dendritic spines through a myosin V-dependent pathway. We propose that caldendrin transforms myosin into a stationary F-actin tether that enables the localization of ER tubules and formation of the spine apparatus in dendritic spines.
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Affiliation(s)
- Anja Konietzny
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Jasper Grendel
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Alan Kadek
- Leibniz Institute for Experimental Virology (HPI)HamburgGermany
- European XFEL GmbHSchenefeldGermany
| | - Michael Bucher
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Yuhao Han
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
| | - Nathalie Hertrich
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | | | | | - Kay Grünewald
- Leibniz Institute for Experimental Virology (HPI)HamburgGermany
- Centre for Structural Systems BiologyHamburgGermany
- Department of ChemistryUniversity of HamburgHamburgGermany
| | - Charlotte Uetrecht
- Leibniz Institute for Experimental Virology (HPI)HamburgGermany
- European XFEL GmbHSchenefeldGermany
- Centre for Structural Systems BiologyHamburgGermany
| | - Marina Mikhaylova
- RG OptobiologyInstitute of BiologyHumboldt Universität zu BerlinBerlinGermany
- Guest Group Neuronal Protein TransportCenter for Molecular NeurobiologyZMNHUniversity Medical Center Hamburg‐EppendorfHamburgGermany
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16
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Troilo F, Pedretti M, Travaglini-Allocatelli C, Astegno A, Di Matteo A. Rapid kinetics of calcium dissociation from plant calmodulin and calmodulin-like proteins and effect of target peptides. Biochem Biophys Res Commun 2022; 590:103-108. [PMID: 34974297 DOI: 10.1016/j.bbrc.2021.12.077] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 12/21/2021] [Indexed: 11/02/2022]
Abstract
Calcium (Ca2+) signaling represents a universal information code in plants, playing crucial roles spanning developmental processes to stress responses. Ca2+ signals are decoded into defined plant adaptive responses by different Ca2+ sensing proteins, including calmodulin (CaM) and calmodulin-like (CML) proteins. Although major advances have been achieved in describing how these Ca2+ decoding proteins interact and regulate downstream target effectors, the molecular details of these processes remain largely unknown. Herein, the kinetics of Ca2+ dissociation from a conserved CaM and two CML isoforms from A. thaliana has been studied by fluorescence stopped-flow spectroscopy. Kinetic data were obtained for the isolated Ca2+-bound proteins as well as for the proteins complexed with different target peptides. Moreover, the lobe specific interactions between the Ca2+ sensing proteins and their targets were characterized by using a panel of protein mutants deficient in Ca2+ binding at the N-lobe or C-lobe. Results were analyzed and discussed in the context of the Ca2+-decoding and Ca2+-controlled target binding mechanisms in plants.
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Affiliation(s)
- Francesca Troilo
- CNR Institute of Molecular Biology and Pathology, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Marco Pedretti
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | | | - Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy.
| | - Adele Di Matteo
- CNR Institute of Molecular Biology and Pathology, P.le Aldo Moro 5, 00185, Rome, Italy.
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17
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Zhang Y, Zhang Y, Pan X, Qin Y, Deng J, Wang S, Gao Q, Zhu Y, Yang Z, Lu X. Molecular insights on Ca2+/Na+ separation via graphene-based nanopores: The role of electrostatic interactions to ionic dehydration. Chin J Chem Eng 2021. [DOI: 10.1016/j.cjche.2021.10.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Vuong-Brender TT, Flynn S, Vallis Y, de Bono M. Neuronal calmodulin levels are controlled by CAMTA transcription factors. eLife 2021; 10:68238. [PMID: 34499028 PMCID: PMC8428840 DOI: 10.7554/elife.68238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 08/28/2021] [Indexed: 01/18/2023] Open
Abstract
The ubiquitous Ca2+ sensor calmodulin (CaM) binds and regulates many proteins, including ion channels, CaM kinases, and calcineurin, according to Ca2+-CaM levels. What regulates neuronal CaM levels, is, however, unclear. CaM-binding transcription activators (CAMTAs) are ancient proteins expressed broadly in nervous systems and whose loss confers pleiotropic behavioral defects in flies, mice, and humans. Using Caenorhabditis elegans and Drosophila, we show that CAMTAs control neuronal CaM levels. The behavioral and neuronal Ca2+ signaling defects in mutants lacking camt-1, the sole C. elegans CAMTA, can be rescued by supplementing neuronal CaM. CAMT-1 binds multiple sites in the CaM promoter and deleting these sites phenocopies camt-1. Our data suggest CAMTAs mediate a conserved and general mechanism that controls neuronal CaM levels, thereby regulating Ca2+ signaling, physiology, and behavior.
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Affiliation(s)
- Thanh Thi Vuong-Brender
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Sean Flynn
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Yvonne Vallis
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Mario de Bono
- Cell Biology Division, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
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19
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Garg V, Suzuki J, Paranjpe I, Unsulangi T, Boyman L, Milescu LS, Lederer WJ, Kirichok Y. The mechanism of MICU-dependent gating of the mitochondrial Ca 2+uniporter. eLife 2021; 10:e69312. [PMID: 34463251 PMCID: PMC8437439 DOI: 10.7554/elife.69312] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 08/09/2021] [Indexed: 12/11/2022] Open
Abstract
Ca2+ entry into mitochondria is through the mitochondrial calcium uniporter complex (MCUcx), a Ca2+-selective channel composed of five subunit types. Two MCUcx subunits (MCU and EMRE) span the inner mitochondrial membrane, while three Ca2+-regulatory subunits (MICU1, MICU2, and MICU3) reside in the intermembrane space. Here, we provide rigorous analysis of Ca2+ and Na+ fluxes via MCUcx in intact isolated mitochondria to understand the function of MICU subunits. We also perform direct patch clamp recordings of macroscopic and single MCUcx currents to gain further mechanistic insights. This comprehensive analysis shows that the MCUcx pore, composed of the EMRE and MCU subunits, is not occluded nor plugged by MICUs during the absence or presence of extramitochondrial Ca2+ as has been widely reported. Instead, MICUs potentiate activity of MCUcx as extramitochondrial Ca2+ is elevated. MICUs achieve this by modifying the gating properties of MCUcx allowing it to spend more time in the open state.
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Affiliation(s)
- Vivek Garg
- Department of Physiology, University of California San FranciscoSan FranciscoUnited States
- Department of Physiology, University of MarylandBaltimoreUnited States
| | - Junji Suzuki
- Department of Physiology, University of California San FranciscoSan FranciscoUnited States
| | - Ishan Paranjpe
- Department of Physiology, University of California San FranciscoSan FranciscoUnited States
| | - Tiffany Unsulangi
- Department of Physiology, University of California San FranciscoSan FranciscoUnited States
| | - Liron Boyman
- Department of Physiology, University of MarylandBaltimoreUnited States
| | - Lorin S Milescu
- Department of Biology, University of MarylandCollege ParkUnited States
| | | | - Yuriy Kirichok
- Department of Physiology, University of California San FranciscoSan FranciscoUnited States
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20
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Sharma A, Ramena GT, Elble RC. Advances in Intracellular Calcium Signaling Reveal Untapped Targets for Cancer Therapy. Biomedicines 2021; 9:1077. [PMID: 34572262 PMCID: PMC8466575 DOI: 10.3390/biomedicines9091077] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/15/2021] [Accepted: 07/18/2021] [Indexed: 02/07/2023] Open
Abstract
Intracellular Ca2+ distribution is a tightly regulated process. Numerous Ca2+ chelating, storage, and transport mechanisms are required to maintain normal cellular physiology. Ca2+-binding proteins, mainly calmodulin and calbindins, sequester free intracellular Ca2+ ions and apportion or transport them to signaling hubs needing the cations. Ca2+ channels, ATP-driven pumps, and exchangers assist the binding proteins in transferring the ions to and from appropriate cellular compartments. Some, such as the endoplasmic reticulum, mitochondria, and lysosomes, act as Ca2+ repositories. Cellular Ca2+ homeostasis is inefficient without the active contribution of these organelles. Moreover, certain key cellular processes also rely on inter-organellar Ca2+ signaling. This review attempts to encapsulate the structure, function, and regulation of major intracellular Ca2+ buffers, sensors, channels, and signaling molecules before highlighting how cancer cells manipulate them to survive and thrive. The spotlight is then shifted to the slow pace of translating such research findings into anticancer therapeutics. We use the PubMed database to highlight current clinical studies that target intracellular Ca2+ signaling. Drug repurposing and improving the delivery of small molecule therapeutics are further discussed as promising strategies for speeding therapeutic development in this area.
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Affiliation(s)
- Aarushi Sharma
- Department of Pharmacology and Simmons Cancer Institute, Southern Illinois University School of Medicine, Springfield, IL 62702, USA;
| | - Grace T. Ramena
- Department of Aquaculture, University of Arkansas, Pine Bluff, AR 71601, USA;
| | - Randolph C. Elble
- Department of Pharmacology and Simmons Cancer Institute, Southern Illinois University School of Medicine, Springfield, IL 62702, USA;
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21
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Pitzer EM, Williams MT, Vorhees CV. Effects of pyrethroids on brain development and behavior: Deltamethrin. Neurotoxicol Teratol 2021; 87:106983. [PMID: 33848594 PMCID: PMC8440325 DOI: 10.1016/j.ntt.2021.106983] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/09/2021] [Accepted: 04/05/2021] [Indexed: 12/12/2022]
Abstract
Deltamethrin (DLM) is a Type II pyrethroid pesticide widely used in agriculture, homes, public spaces, and medicine. Epidemiological studies report that increased pyrethroid exposure during development is associated with neurobehavioral disorders. This raises concern about the safety of these chemicals for children. Few animal studies have explored the long-term effects of developmental exposure to DLM on the brain. Here we review the CNS effects of pyrethroids, with emphasis on DLM. Current data on behavioral and cognitive effects after developmental exposure are emphasized. Although, the acute mechanisms of action of DLM are known, how these translate to long-term effects is only beginning to be understood. But existing data clearly show there are lasting effects on locomotor activity, acoustic startle, learning and memory, apoptosis, and dopamine in mice and rats after early exposure. The most consistent neurochemical findings are reductions in the dopamine transporter and the dopamine D1 receptor. The data show that DLM is developmentally neurotoxic but more research on its mechanisms of long-term effects is needed.
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Affiliation(s)
- Emily M Pitzer
- Dept. of Pediatrics, University of Cincinnati College of Medicine, Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States of America; Environmental Protection Agency, Office of Research and Development, Research Triangle Park, NC 27709, United States of America.
| | - Michael T Williams
- Dept. of Pediatrics, University of Cincinnati College of Medicine, Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States of America.
| | - Charles V Vorhees
- Dept. of Pediatrics, University of Cincinnati College of Medicine, Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States of America.
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22
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Zhang P, Han J, Cieplak P, Cheung MS. Determining the atomic charge of calcium ion requires the information of its coordination geometry in an EF-hand motif. J Chem Phys 2021; 154:124104. [PMID: 33810667 DOI: 10.1063/5.0037517] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
It is challenging to parameterize the force field for calcium ions (Ca2+) in calcium-binding proteins because of their unique coordination chemistry that involves the surrounding atoms required for stability. In this work, we observed a wide variation in Ca2+ binding loop conformations of the Ca2+-binding protein calmodulin, which adopts the most populated ternary structures determined from the molecular dynamics simulations, followed by ab initio quantum mechanical (QM) calculations on all 12 amino acids in the loop that coordinate Ca2+ in aqueous solution. Ca2+ charges were derived by fitting to the electrostatic potential in the context of a classical or polarizable force field (PFF). We discovered that the atomic radius of Ca2+ in conventional force fields is too large for the QM calculation to capture the variation in the coordination geometry of Ca2+ in its ionic form, leading to unphysical charges. Specifically, we found that the fitted atomic charges of Ca2+ in the context of PFF depend on the coordinating geometry of electronegative atoms from the amino acids in the loop. Although nearby water molecules do not influence the atomic charge of Ca2+, they are crucial for compensating for the coordination of Ca2+ due to the conformational flexibility in the EF-hand loop. Our method advances the development of force fields for metal ions and protein binding sites in dynamic environments.
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Affiliation(s)
- Pengzhi Zhang
- Department of Physics, University of Houston, Houston, Texas 77204, USA
| | - Jaebeom Han
- Department of Physics, University of Houston, Houston, Texas 77204, USA
| | - Piotr Cieplak
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, USA
| | - Margaret S Cheung
- Department of Physics, University of Houston, Houston, Texas 77204, USA
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23
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Chen Y, Matveev V. Stationary Ca 2+ nanodomains in the presence of buffers with two binding sites. Biophys J 2021; 120:1942-1956. [PMID: 33771472 DOI: 10.1016/j.bpj.2021.03.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 03/06/2021] [Accepted: 03/11/2021] [Indexed: 10/21/2022] Open
Abstract
We examine closed-form approximations for the equilibrium Ca2+ and buffer concentrations near a point Ca2+ source representing a Ca2+ channel, in the presence of a mobile buffer with two Ca2+ binding sites activated sequentially and possessing distinct binding affinities and kinetics. This allows us to model the impact on Ca2+ nanodomains of realistic endogenous Ca2+ buffers characterized by cooperative Ca2+ binding, such as calretinin. The approximations we present involve a combination or rational and exponential functions, whose parameters are constrained using the series interpolation method that we recently introduced for the case of simpler Ca2+ buffers with a single Ca2+ binding site. We conduct extensive parameter sensitivity analysis and show that the obtained closed-form approximations achieve reasonable qualitative accuracy for a wide range of buffer's Ca2+ binding properties and other relevant model parameters. In particular, the accuracy of the derived approximants exceeds that of the rapid buffering approximation in large portions of the relevant parameter space.
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Affiliation(s)
- Yinbo Chen
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey
| | - Victor Matveev
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey.
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24
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Jain K, Lavista-Llanos S, Grabe V, Hansson BS, Wicher D. Calmodulin regulates the olfactory performance in Drosophila melanogaster. Sci Rep 2021; 11:3747. [PMID: 33580172 PMCID: PMC7881240 DOI: 10.1038/s41598-021-83296-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 02/01/2021] [Indexed: 12/01/2022] Open
Abstract
Insect odorant receptors (ORs) detect volatile chemical cues with high sensitivity. These ORs operate as ligand-gated ion channels and are formed by heptahelical OrX and Orco (co-receptor) proteins. A highly conserved calmodulin (CaM) binding site (CBS) 336SAIKYWVER344 within the second intracellular loop of Drosophila melanogaster Orco constitutes a target for regulating OR performance. Here we asked how a point mutation K339N in this CBS affects the olfactory performance of Drosophila melanogaster. We first asked how this mutation would affect the odor responses of olfactory sensory neurons (OSNs). Using Ca2+ imaging in an ex-vivo antenna preparation, we activated all OR (OrX/Orco) expressing neurons using the synthetic agonist VUAA1. In a next attempt, we restricted the OR spectrum to Or22a expressing neurons (Or22a/Orco) and stimulated these OSNs with the ligand ethyl hexanoate. In both approaches, we found that flies carrying the K339N point mutation in Orco display a reduced olfactory response. We also found that the mutation abolishes the capability of OSNs to sensitize by repeated weak odor stimuli. Next, we asked whether OrcoK339N might affect the odor localization performance. Using a wind tunnel bioassay, we found that odor localization in flies carrying the OrcoK339N mutation was severely diminished.
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Affiliation(s)
- Kalpana Jain
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745, Jena, Germany
| | - Sofia Lavista-Llanos
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745, Jena, Germany
| | - Veit Grabe
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745, Jena, Germany
| | - Bill S Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745, Jena, Germany
| | - Dieter Wicher
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745, Jena, Germany.
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25
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Mochida S. Neurotransmitter Release Site Replenishment and Presynaptic Plasticity. Int J Mol Sci 2020; 22:ijms22010327. [PMID: 33396919 PMCID: PMC7794938 DOI: 10.3390/ijms22010327] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 12/23/2020] [Accepted: 12/27/2020] [Indexed: 12/19/2022] Open
Abstract
An action potential (AP) triggers neurotransmitter release from synaptic vesicles (SVs) docking to a specialized release site of presynaptic plasma membrane, the active zone (AZ). The AP simultaneously controls the release site replenishment with SV for sustainable synaptic transmission in response to incoming neuronal signals. Although many studies have suggested that the replenishment time is relatively slow, recent studies exploring high speed resolution have revealed SV dynamics with milliseconds timescale after an AP. Accurate regulation is conferred by proteins sensing Ca2+ entering through voltage-gated Ca2+ channels opened by an AP. This review summarizes how millisecond Ca2+ dynamics activate multiple protein cascades for control of the release site replenishment with release-ready SVs that underlie presynaptic short-term plasticity.
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Affiliation(s)
- Sumiko Mochida
- Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan
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26
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Zhang L, Ding W, Ji Y. Analgesic effect of pulsed electromagnetic fields for mammaplasty: A meta-analysis of randomized controlled studies. Medicine (Baltimore) 2020; 99:e21449. [PMID: 32871867 PMCID: PMC7458251 DOI: 10.1097/md.0000000000021449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/18/2020] [Accepted: 06/24/2020] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Pulsed electromagnetic fields shows some potential in alleviating pain after mammaplasty. This systematic review and meta-analysis is conducted to investigate the analgesic efficacy of pulsed electromagnetic fields for pain control after mammaplasty. METHODS The databases including PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases are systematically searched for collecting the randomized controlled trials regarding the impact of pulsed electromagnetic fields on pain intensity after mammaplasty. RESULTS This meta-analysis has included 4 randomized controlled trials. Compared with control group after mammaplasty, pulsed electromagnetic fields results in remarkably reduced pain scores on 1 day (MD = -1.34; 95% confidence interval [CI] = -2.23 to -0.45; P = .003) and 3 days (MD = -1.86; 95% CI = -3.23 to -0.49; P = .008), as well as analgesic consumption (Std. MD = -5.64; 95% CI = -7.26 to -4.02; P < .00001). CONCLUSIONS Pulsed electromagnetic fields is associated with substantially reduced pain intensity after mammaplasty.
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Affiliation(s)
- Li Zhang
- Department of Plastic Surgery, The First people's Hospital of Xiaoshan
| | - Wei Ding
- Department of Plastic Surgery, The First people's Hospital of Xiaoshan
| | - Yu Ji
- Department of Plastic Surgery, Zhejiang Provincial People's Hospital, People's Hospital of Hangzhou Medical College, Hangzhou; Zhejiang Province, P.R. China
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27
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Song Y, Xie L, Lee Y, Brede DA, Lyne F, Kassaye Y, Thaulow J, Caldwell G, Salbu B, Tollefsen KE. Integrative assessment of low-dose gamma radiation effects on Daphnia magna reproduction: Toxicity pathway assembly and AOP development. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 705:135912. [PMID: 31846819 DOI: 10.1016/j.scitotenv.2019.135912] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 11/25/2019] [Accepted: 12/01/2019] [Indexed: 06/10/2023]
Abstract
High energy gamma radiation is potentially hazardous to organisms, including aquatic invertebrates. Although extensively studied in a number of invertebrate species, knowledge on effects induced by gamma radiation is to a large extent limited to the induction of oxidative stress and DNA damage at the molecular/cellular level, or survival, growth and reproduction at the organismal level. As the knowledge of causal relationships between effects occurring at different levels of biological organization is scarce, the ability to provide mechanistic explanation for observed adverse effects is limited, and thus development of Adverse Outcome Pathways (AOPs) and larger scale implementation into next generation hazard and risk predictions is restricted. The present study was therefore conducted to assess the effects of high-energy gamma radiation from cobalt-60 across multiple levels of biological organization (i.e., molecular, cellular, tissue, organ and individual) and characterize the major toxicity pathways leading to impaired reproduction in the model freshwater crustacean Daphnia magna (water flea). Following gamma exposure, a number of bioassays were integrated to measure relevant toxicological endpoints such as gene expression, reactive oxygen species (ROS), lipid peroxidation (LPO), neutral lipid storage, adenosine triphosphate (ATP) content, apoptosis, ovary histology and reproduction. A non-monotonic pattern was consistently observed across the levels of biological organization, albeit with some variation at the lower end of the dose-rate scale, indicating a complex response to radiation doses. By integrating results from different bioassays, a novel pathway network describing the key toxicity pathways involved in the reproductive effects of gamma radiation were proposed, such as DNA damage-oocyte apoptosis pathway, LPO-ATP depletion pathway, calcium influx-endocrine disruption pathway and DNA hypermethylation pathway. Three novel AOPs were proposed for oxidative stressor-mediated excessive ROS formation leading to reproductive effect, and thus introducing the world's first AOPs for non-chemical stressors in aquatic invertebrates.
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Affiliation(s)
- You Song
- Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 OSLO, Norway; Centre for Environmental Radioactivity (CERAD), Norwegian University of Life Sciences (NMBU), Post box 5003, N-1432 Ås, Norway.
| | - Li Xie
- Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 OSLO, Norway; Centre for Environmental Radioactivity (CERAD), Norwegian University of Life Sciences (NMBU), Post box 5003, N-1432 Ås, Norway; Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management (MINA), P.O. Box 5003, N-1432 Ås, Norway
| | - YeonKyeong Lee
- Centre for Environmental Radioactivity (CERAD), Norwegian University of Life Sciences (NMBU), Post box 5003, N-1432 Ås, Norway; Norwegian University of Life Sciences (NMBU), Faculty of Biosciences, P.O. Box 5003, N-1432 Ås, Norway
| | - Dag Anders Brede
- Centre for Environmental Radioactivity (CERAD), Norwegian University of Life Sciences (NMBU), Post box 5003, N-1432 Ås, Norway; Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management (MINA), P.O. Box 5003, N-1432 Ås, Norway
| | - Fern Lyne
- Centre for Environmental Radioactivity (CERAD), Norwegian University of Life Sciences (NMBU), Post box 5003, N-1432 Ås, Norway; Newcastle University, Newcastle upon Tyne, UK
| | - Yetneberk Kassaye
- Centre for Environmental Radioactivity (CERAD), Norwegian University of Life Sciences (NMBU), Post box 5003, N-1432 Ås, Norway; Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management (MINA), P.O. Box 5003, N-1432 Ås, Norway
| | - Jens Thaulow
- Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 OSLO, Norway; Centre for Environmental Radioactivity (CERAD), Norwegian University of Life Sciences (NMBU), Post box 5003, N-1432 Ås, Norway
| | | | - Brit Salbu
- Centre for Environmental Radioactivity (CERAD), Norwegian University of Life Sciences (NMBU), Post box 5003, N-1432 Ås, Norway; Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management (MINA), P.O. Box 5003, N-1432 Ås, Norway
| | - Knut Erik Tollefsen
- Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, N-0349 OSLO, Norway; Centre for Environmental Radioactivity (CERAD), Norwegian University of Life Sciences (NMBU), Post box 5003, N-1432 Ås, Norway; Norwegian University of Life Sciences (NMBU), Faculty of Environmental Sciences and Natural Resource Management (MINA), P.O. Box 5003, N-1432 Ås, Norway
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O’Day DH, Taylor RJ, Myre MA. Calmodulin and Calmodulin Binding Proteins in Dictyostelium: A Primer. Int J Mol Sci 2020; 21:E1210. [PMID: 32054133 PMCID: PMC7072818 DOI: 10.3390/ijms21041210] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 01/11/2023] Open
Abstract
Dictyostelium discoideum is gaining increasing attention as a model organism for the study of calcium binding and calmodulin function in basic biological events as well as human diseases. After a short overview of calcium-binding proteins, the structure of Dictyostelium calmodulin and the conformational changes effected by calcium ion binding to its four EF hands are compared to its human counterpart, emphasizing the highly conserved nature of this central regulatory protein. The calcium-dependent and -independent motifs involved in calmodulin binding to target proteins are discussed with examples of the diversity of calmodulin binding proteins that have been studied in this amoebozoan. The methods used to identify and characterize calmodulin binding proteins is covered followed by the ways Dictyostelium is currently being used as a system to study several neurodegenerative diseases and how it could serve as a model for studying calmodulinopathies such as those associated with specific types of heart arrythmia. Because of its rapid developmental cycles, its genetic tractability, and a richly endowed stock center, Dictyostelium is in a position to become a leader in the field of calmodulin research.
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Affiliation(s)
- Danton H. O’Day
- Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L6L 1X3, Canada
| | - Ryan J. Taylor
- Department of Biological Sciences, Kennedy College of Sciences, University of Massachusetts Lowell, Lowell, MA 01854, USA; (R.J.T.); (M.A.M.)
| | - Michael A. Myre
- Department of Biological Sciences, Kennedy College of Sciences, University of Massachusetts Lowell, Lowell, MA 01854, USA; (R.J.T.); (M.A.M.)
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29
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Li L, Lai M, Cole S, Le Novère N, Edelstein SJ. Neurogranin stimulates Ca2+/calmodulin-dependent kinase II by suppressing calcineurin activity at specific calcium spike frequencies. PLoS Comput Biol 2020; 16:e1006991. [PMID: 32049957 PMCID: PMC7041932 DOI: 10.1371/journal.pcbi.1006991] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 02/25/2020] [Accepted: 11/18/2019] [Indexed: 11/18/2022] Open
Abstract
Calmodulin sits at the center of molecular mechanisms underlying learning and memory. Its complex and sometimes opposite influences, mediated via the binding to various proteins, are yet to be fully understood. Calcium/calmodulin-dependent protein kinase II (CaMKII) and calcineurin (CaN) both bind open calmodulin, favoring Long-Term Potentiation (LTP) or Depression (LTD) respectively. Neurogranin binds to the closed conformation of calmodulin and its impact on synaptic plasticity is less clear. We set up a mechanistic computational model based on allosteric principles to simulate calmodulin state transitions and its interactions with calcium ions and the three binding partners mentioned above. We simulated calcium spikes at various frequencies and show that neurogranin regulates synaptic plasticity along three modalities. At low spike frequencies, neurogranin inhibits the onset of LTD by limiting CaN activation. At intermediate frequencies, neurogranin facilitates LTD, but limits LTP by precluding binding of CaMKII with calmodulin. Finally, at high spike frequencies, neurogranin promotes LTP by enhancing CaMKII autophosphorylation. While neurogranin might act as a calmodulin buffer, it does not significantly preclude the calmodulin opening by calcium. On the contrary, neurogranin synchronizes the opening of calmodulin's two lobes and promotes their activation at specific frequencies. Neurogranin suppresses basal CaN activity, thus increasing the chance of CaMKII trans-autophosphorylation at high-frequency calcium spikes. Taken together, our study reveals dynamic regulatory roles played by neurogranin on synaptic plasticity, which provide mechanistic explanations for opposing experimental findings.
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Affiliation(s)
- Lu Li
- Babraham Institute, Cambridge, United Kingdom
| | - Massimo Lai
- Quantitative Systems Pharmacology, CERTARA, Canterbury, United Kingdom
| | - Stephen Cole
- Cambridge Systems Biology Centre, University of Cambridge, Cambridge, United Kingdom
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Quantitation and Simulation of Single Action Potential-Evoked Ca 2+ Signals in CA1 Pyramidal Neuron Presynaptic Terminals. eNeuro 2019; 6:ENEURO.0343-19.2019. [PMID: 31551250 PMCID: PMC6800293 DOI: 10.1523/eneuro.0343-19.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 09/10/2019] [Indexed: 01/07/2023] Open
Abstract
Presynaptic Ca2+ evokes exocytosis, endocytosis, and synaptic plasticity. However, Ca2+ flux and interactions at presynaptic molecular targets are difficult to quantify because fluorescence imaging has limited resolution. In rats of either sex, we measured single varicosity presynaptic Ca2+ using Ca2+ dyes as buffers, and constructed models of Ca2+ dispersal. Action potentials evoked Ca2+ transients with little variation when measured with low-affinity dye (peak amplitude 789 ± 39 nM, within 2 ms of stimulation; decay times, 119 ± 10 ms). Endogenous Ca2+ buffering capacity, action potential-evoked free [Ca2+]i, and total Ca2+ amounts entering terminals were determined using Ca2+ dyes as buffers. These data constrained Monte Carlo (MCell) simulations of Ca2+ entry, buffering, and removal. Simulations of experimentally-determined Ca2+ fluxes, buffered by simulated calbindin28K well fit data, and were consistent with clustered Ca2+ entry followed within 4 ms by diffusion throughout the varicosity. Repetitive stimulation caused free varicosity Ca2+ to sum. However, simulated in nanometer domains, its removal by pumps and buffering was negligible, while local diffusion dominated. Thus, Ca2+ within tens of nanometers of entry, did not accumulate. A model of synaptotagmin1 (syt1)-Ca2+ binding indicates that even with 10 µM free varicosity evoked Ca2+, syt1 must be within tens of nanometers of channels to ensure occupation of all its Ca2+-binding sites. Repetitive stimulation, evoking short-term synaptic enhancement, does not modify probabilities of Ca2+ fully occupying syt1’s C2 domains, suggesting that enhancement is not mediated by Ca2+-syt1 interactions. We conclude that at spatiotemporal scales of fusion machines, Ca2+ necessary for their activation is diffusion dominated.
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31
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Ohadi D, Schmitt DL, Calabrese B, Halpain S, Zhang J, Rangamani P. Computational Modeling Reveals Frequency Modulation of Calcium-cAMP/PKA Pathway in Dendritic Spines. Biophys J 2019; 117:1963-1980. [PMID: 31668749 PMCID: PMC7031750 DOI: 10.1016/j.bpj.2019.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 07/30/2019] [Accepted: 10/02/2019] [Indexed: 12/20/2022] Open
Abstract
Dendritic spines are the primary excitatory postsynaptic sites that act as subcompartments of signaling. Ca2+ is often the first and most rapid signal in spines. Downstream of calcium, the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway plays a critical role in the regulation of spine formation, morphological modifications, and ultimately, learning and memory. Although the dynamics of calcium are reasonably well-studied, calcium-induced cAMP/PKA dynamics, particularly with respect to frequency modulation, are not fully explored. In this study, we present a well-mixed model for the dynamics of calcium-induced cAMP/PKA dynamics in dendritic spines. The model is constrained using experimental observations in the literature. Further, we measured the calcium oscillation frequency in dendritic spines of cultured hippocampal CA1 neurons and used these dynamics as model inputs. Our model predicts that the various steps in this pathway act as frequency modulators for calcium, and the high frequency of calcium input is filtered by adenylyl cyclase 1 and phosphodiesterases in this pathway such that cAMP/PKA only responds to lower frequencies. This prediction has important implications for noise filtering and long-timescale signal transduction in dendritic spines. A companion manuscript presents a three-dimensional spatial model for the same pathway.
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Affiliation(s)
- Donya Ohadi
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California
| | - Danielle L Schmitt
- Department of Pharmacology, University of California San Diego, La Jolla, California
| | - Barbara Calabrese
- Division of Biological Sciences and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California
| | - Shelley Halpain
- Division of Biological Sciences and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California
| | - Jin Zhang
- Department of Pharmacology, University of California San Diego, La Jolla, California
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California.
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32
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Mahajan G, Nadkarni S. Intracellular calcium stores mediate metaplasticity at hippocampal dendritic spines. J Physiol 2019; 597:3473-3502. [PMID: 31099020 PMCID: PMC6636706 DOI: 10.1113/jp277726] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/16/2019] [Indexed: 12/21/2022] Open
Abstract
Key points Calcium (Ca2+) entry mediated by NMDA receptors is considered central to the induction of activity‐dependent synaptic plasticity in hippocampal area CA1; this description does not, however, take into account the potential contribution of endoplasmic reticulum (ER) Ca2+ stores. The ER has a heterogeneous distribution in CA1 dendritic spines, and may introduce localized functional differences in Ca2+ signalling between synapses, as suggested by experiments on metabotropic receptor‐dependent long‐term depression. A physiologically detailed computational model of Ca2+ dynamics at a CA3–CA1 excitatory synapse characterizes the contribution of spine ER via metabotropic signalling during plasticity induction protocols. ER Ca2+ release via IP3 receptors modulates NMDA receptor‐dependent plasticity in a graded manner, to selectively promote synaptic depression with relatively diminished effect on LTP induction; this may temper further strengthening at the stronger synapses which are preferentially associated with ER‐containing spines. Acquisition of spine ER may thus represent a local, biophysically plausible ‘metaplastic switch’ at potentiated CA1 synapses, contributing to the plasticity–stability balance in neural circuits.
Abstract Long‐term plasticity mediated by NMDA receptors supports input‐specific, Hebbian forms of learning at excitatory CA3–CA1 connections in the hippocampus. There exists an additional layer of stabilizing mechanisms that act globally as well as locally over multiple time scales to ensure that plasticity occurs in a constrained manner. Here, we investigated the role of calcium (Ca2+) stores associated with the endoplasmic reticulum (ER) in the local regulation of plasticity at individual CA1 synapses. Our study was spurred by (1) the curious observation that ER is sparsely distributed in dendritic spines, but over‐represented in larger spines that are likely to have undergone activity‐dependent strengthening, and (2) evidence suggesting that ER motility at synapses can be rapid, and accompany activity‐regulated spine remodelling. We constructed a physiologically realistic computational model of an ER‐bearing CA1 spine, and examined how IP3‐sensitive Ca2+ stores affect spine Ca2+ dynamics during activity patterns mimicking the induction of long‐term potentiation and long‐term depression (LTD). Our results suggest that the presence of ER modulates NMDA receptor‐dependent plasticity in a graded manner that selectively enhances LTD induction. We propose that ER may locally tune Ca2+‐based plasticity, providing a braking mechanism to mitigate runaway strengthening at potentiated synapses. Our study provides a biophysically accurate description of postsynaptic Ca2+ regulation, and suggests that ER in the spine may promote the re‐use of hippocampal synapses with saturated strengths. Calcium (Ca2+) entry mediated by NMDA receptors is considered central to the induction of activity‐dependent synaptic plasticity in hippocampal area CA1; this description does not, however, take into account the potential contribution of endoplasmic reticulum (ER) Ca2+ stores. The ER has a heterogeneous distribution in CA1 dendritic spines, and may introduce localized functional differences in Ca2+ signalling between synapses, as suggested by experiments on metabotropic receptor‐dependent long‐term depression. A physiologically detailed computational model of Ca2+ dynamics at a CA3–CA1 excitatory synapse characterizes the contribution of spine ER via metabotropic signalling during plasticity induction protocols. ER Ca2+ release via IP3 receptors modulates NMDA receptor‐dependent plasticity in a graded manner, to selectively promote synaptic depression with relatively diminished effect on LTP induction; this may temper further strengthening at the stronger synapses which are preferentially associated with ER‐containing spines. Acquisition of spine ER may thus represent a local, biophysically plausible ‘metaplastic switch’ at potentiated CA1 synapses, contributing to the plasticity–stability balance in neural circuits.
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Affiliation(s)
- Gaurang Mahajan
- Indian Institute of Science Education and Research, Pune, 411 008, India
| | - Suhita Nadkarni
- Indian Institute of Science Education and Research, Pune, 411 008, India
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33
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Presynaptic Calcium Channels. Int J Mol Sci 2019; 20:ijms20092217. [PMID: 31064106 PMCID: PMC6539076 DOI: 10.3390/ijms20092217] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 04/22/2019] [Accepted: 04/26/2019] [Indexed: 12/27/2022] Open
Abstract
Presynaptic Ca2+ entry occurs through voltage-gated Ca2+ (CaV) channels which are activated by membrane depolarization. Depolarization accompanies neuronal firing and elevation of Ca2+ triggers neurotransmitter release from synaptic vesicles. For synchronization of efficient neurotransmitter release, synaptic vesicles are targeted by presynaptic Ca2+ channels forming a large signaling complex in the active zone. The presynaptic CaV2 channel gene family (comprising CaV2.1, CaV2.2, and CaV2.3 isoforms) encode the pore-forming α1 subunit. The cytoplasmic regions are responsible for channel modulation by interacting with regulatory proteins. This article overviews modulation of the activity of CaV2.1 and CaV2.2 channels in the control of synaptic strength and presynaptic plasticity.
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34
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Burgoyne RD, Helassa N, McCue HV, Haynes LP. Calcium Sensors in Neuronal Function and Dysfunction. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a035154. [PMID: 30833454 DOI: 10.1101/cshperspect.a035154] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Calcium signaling in neurons as in other cell types can lead to varied changes in cellular function. Neuronal Ca2+ signaling processes have also become adapted to modulate the function of specific pathways over a wide variety of time domains and these can have effects on, for example, axon outgrowth, neuronal survival, and changes in synaptic strength. Ca2+ also plays a key role in synapses as the trigger for fast neurotransmitter release. Given its physiological importance, abnormalities in neuronal Ca2+ signaling potentially underlie many different neurological and neurodegenerative diseases. The mechanisms by which changes in intracellular Ca2+ concentration in neurons can bring about diverse responses is underpinned by the roles of ubiquitous or specialized neuronal Ca2+ sensors. It has been established that synaptotagmins have key functions in neurotransmitter release, and, in addition to calmodulin, other families of EF-hand-containing neuronal Ca2+ sensors, including the neuronal calcium sensor (NCS) and the calcium-binding protein (CaBP) families, play important physiological roles in neuronal Ca2+ signaling. It has become increasingly apparent that these various Ca2+ sensors may also be crucial for aspects of neuronal dysfunction and disease either indirectly or directly as a direct consequence of genetic variation or mutations. An understanding of the molecular basis for the regulation of the targets of the Ca2+ sensors and the physiological roles of each protein in identified neurons may contribute to future approaches to the development of treatments for a variety of human neuronal disorders.
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Affiliation(s)
- Robert D Burgoyne
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Nordine Helassa
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Hannah V McCue
- Centre for Genomic Research, University of Liverpool, Liverpool, United Kingdom
| | - Lee P Haynes
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
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35
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Archer CR, Enslow BT, Taylor AB, De la Rosa V, Bhattacharya A, Shapiro MS. A mutually induced conformational fit underlies Ca 2+-directed interactions between calmodulin and the proximal C terminus of KCNQ4 K + channels. J Biol Chem 2019; 294:6094-6112. [PMID: 30808708 PMCID: PMC6463706 DOI: 10.1074/jbc.ra118.006857] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/24/2019] [Indexed: 11/06/2022] Open
Abstract
Calmodulin (CaM) conveys intracellular Ca2+ signals to KCNQ (Kv7, "M-type") K+ channels and many other ion channels. Whether this "calmodulation" involves a dramatic structural rearrangement or only slight perturbations of the CaM/KCNQ complex is as yet unclear. A consensus structural model of conformational shifts occurring between low nanomolar and physiologically high intracellular [Ca2+] is still under debate. Here, we used various techniques of biophysical chemical analyses to investigate the interactions between CaM and synthetic peptides corresponding to the A and B domains of the KCNQ4 subtype. We found that in the absence of CaM, the peptides are disordered, whereas Ca2+/CaM imposed helical structure on both KCNQ A and B domains. Isothermal titration calorimetry revealed that Ca2+/CaM has higher affinity for the B domain than for the A domain of KCNQ2-4 and much higher affinity for the B domain when prebound with the A domain. X-ray crystallography confirmed that these discrete peptides spontaneously form a complex with Ca2+/CaM, similar to previous reports of CaM binding KCNQ-AB domains that are linked together. Microscale thermophoresis and heteronuclear single-quantum coherence NMR spectroscopy indicated the C-lobe of Ca2+-free CaM to interact with the KCNQ4 B domain (Kd ∼10-20 μm), with increasing Ca2+ molar ratios shifting the CaM-B domain interactions via only the CaM C-lobe to also include the N-lobe. Our findings suggest that in response to increased Ca2+, CaM undergoes lobe switching that imposes a dramatic mutually induced conformational fit to both the proximal C terminus of KCNQ4 channels and CaM, likely underlying Ca2+-dependent regulation of KCNQ gating.
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Affiliation(s)
- Crystal R Archer
- From the Departments of Cell and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas 78229; Departments of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas 78229
| | - Benjamin T Enslow
- the Long School of Medicine, University of Texas Health San Antonio, San Antonio, Texas 78229
| | - Alexander B Taylor
- Departments of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas 78229
| | - Victor De la Rosa
- From the Departments of Cell and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas 78229
| | - Akash Bhattacharya
- Departments of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, Texas 78229
| | - Mark S Shapiro
- From the Departments of Cell and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas 78229.
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36
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Jensen TP, Zheng K, Cole N, Marvin JS, Looger LL, Rusakov DA. Multiplex imaging relates quantal glutamate release to presynaptic Ca 2+ homeostasis at multiple synapses in situ. Nat Commun 2019; 10:1414. [PMID: 30926781 PMCID: PMC6441074 DOI: 10.1038/s41467-019-09216-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 02/25/2019] [Indexed: 12/17/2022] Open
Abstract
Information processing by brain circuits depends on Ca2+-dependent, stochastic release of the excitatory neurotransmitter glutamate. Whilst optical glutamate sensors have enabled detection of synaptic discharges, understanding presynaptic machinery requires simultaneous readout of glutamate release and nanomolar presynaptic Ca2+ in situ. Here, we find that the fluorescence lifetime of the red-shifted Ca2+ indicator Cal-590 is Ca2+-sensitive in the nanomolar range, and employ it in combination with green glutamate sensors to relate quantal neurotransmission to presynaptic Ca2+ kinetics. Multiplexed imaging of individual and multiple synapses in identified axonal circuits reveals that glutamate release efficacy, but not its short-term plasticity, varies with time-dependent fluctuations in presynaptic resting Ca2+ or spike-evoked Ca2+ entry. Within individual presynaptic boutons, we find no nanoscopic co-localisation of evoked presynaptic Ca2+ entry with the prevalent glutamate release site, suggesting loose coupling between the two. The approach enables a better understanding of release machinery at central synapses.
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Affiliation(s)
- Thomas P Jensen
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK.
| | - Kaiyu Zheng
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK
| | - Nicholas Cole
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK
| | - Jonathan S Marvin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, 20147, VA, USA
| | - Loren L Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, 20147, VA, USA
| | - Dmitri A Rusakov
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK.
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Kerruth S, Coates C, Dürst CD, Oertner TG, Török K. The kinetic mechanisms of fast-decay red-fluorescent genetically encoded calcium indicators. J Biol Chem 2019; 294:3934-3946. [PMID: 30651353 PMCID: PMC6422079 DOI: 10.1074/jbc.ra118.004543] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 01/14/2019] [Indexed: 01/06/2023] Open
Abstract
Genetically encoded calcium indicators (GECIs) are useful reporters of cell-signaling, neuronal, and network activities. We have generated novel fast variants and investigated the kinetic mechanisms of two recently developed red-fluorescent GECIs (RGECIs), mApple-based jRGECO1a and mRuby-based jRCaMP1a. In the formation of fluorescent jRGECO1a and jRCaMP1a complexes, calcium binding is followed by rate-limiting isomerization. However, fluorescence decay of calcium-bound jRGECO1a follows a different pathway from its formation: dissociation of calcium occurs first, followed by the peptide, similarly to GCaMP-s. In contrast, fluorescence decay of calcium-bound jRCaMP1a occurs by the reversal of the on-pathway: peptide dissociation is followed by calcium. The mechanistic differences explain the generally slower off-kinetics of jRCaMP1a-type indicators compared with GCaMP-s and jRGECO1a-type GECI: the fluorescence decay rate of f-RCaMP1 was 21 s-1, compared with 109 s-1 for f-RGECO1 and f-RGECO2 (37 °C). Thus, the CaM-peptide interface is an important determinant of the kinetic responses of GECIs; however, the topology of the structural link to the fluorescent protein demonstrably affects the internal dynamics of the CaM-peptide complex. In the dendrites of hippocampal CA3 neurons, f-RGECO1 indicates calcium elevation in response to a 100 action potential train in a linear fashion, making the probe particularly useful for monitoring large-amplitude, fast signals, e.g. those in dendrites, muscle cells, and immune cells.
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Affiliation(s)
- Silke Kerruth
- From the Molecular and Clinical Sciences Research Institute, St. George's, University of London, London SW17 0RE, United Kingdom and
| | - Catherine Coates
- From the Molecular and Clinical Sciences Research Institute, St. George's, University of London, London SW17 0RE, United Kingdom and
| | - Céline D Dürst
- the Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, 20251 Hamburg, Germany
| | - Thomas G Oertner
- the Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, 20251 Hamburg, Germany
| | - Katalin Török
- From the Molecular and Clinical Sciences Research Institute, St. George's, University of London, London SW17 0RE, United Kingdom and
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Abstract
Fundamental cell processes such as synaptic neurotransmitter release, endocrine hormone secretion, and myocyte contraction are controlled by highly localized calcium (Ca2+) signals resulting from brief openings of trans-membrane Ca2+ channels. On short temporal and spatial scales, the corresponding local Ca2+ nanodomains formed in the vicinity of a single or several open Ca2+ channels can be effectively approximated by quasi-stationary solutions. The rapid buffering approximation (RBA) is one of the most powerful of such approximations, and is based on the assumption of instantaneous equilibration of the bimolecular Ca2+ buffering reaction, combined with the conservation condition for the total Ca2+ and buffer molecule numbers. Previously, RBA has been generalized to an arbitrary arrangement of Ca2+ channels on a flat membrane, in the presence of any number of simple Ca2+ buffers with one-to-one Ca2+ binding stoichiometry. However, many biological buffers have multiple binding sites. For example, buffers and sensors phylogenetically related to calmodulin consist of two Ca2+-binding domains (lobes), with each domain binding two Ca2+ ions in a cooperative manner. Here we consider an extension of RBA to such buffers with two interdependent Ca2+ binding sites. We show that in the presence of such buffers, RBA solution is given by the solution to a cubic equation, analogous to the quadratic equation describing RBA in the case of a simple, one-to-one Ca2+ buffer. We examine in detail the dependence of RBA accuracy on buffering parameters, to reveal conditions under which RBA provides sufficient precision.
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Affiliation(s)
- Victor Matveev
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey.
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39
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Switching on Endogenous Metal Binding Proteins in Parkinson's Disease. Cells 2019; 8:cells8020179. [PMID: 30791479 PMCID: PMC6406413 DOI: 10.3390/cells8020179] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 01/26/2019] [Accepted: 02/05/2019] [Indexed: 12/28/2022] Open
Abstract
The formation of cytotoxic intracellular protein aggregates is a pathological signature of multiple neurodegenerative diseases. The principle aggregating protein in Parkinson’s disease (PD) and atypical Parkinson’s diseases is α-synuclein (α-syn), which occurs in neural cytoplasmic inclusions. Several factors have been found to trigger α-syn aggregation, including raised calcium, iron, and copper. Transcriptional inducers have been explored to upregulate expression of endogenous metal-binding proteins as a potential neuroprotective strategy. The vitamin-D analogue, calcipotriol, induced increased expression of the neuronal vitamin D-dependent calcium-binding protein, calbindin-D28k, and this significantly decreased the occurrence of α-syn aggregates in cells with transiently raised intracellular free Ca, thereby increasing viability. More recently, the induction of endogenous expression of the Zn and Cu binding protein, metallothionein, by the glucocorticoid analogue, dexamethasone, gave a specific reduction in Cu-dependent α-syn aggregates. Fe accumulation has long been associated with PD. Intracellularly, Fe is regulated by interactions between the Fe storage protein ferritin and Fe transporters, such as poly(C)-binding protein 1. Analysis of the transcriptional regulation of Fe binding proteins may reveal potential inducers that could modulate Fe homoeostasis in disease. The current review highlights recent studies that suggest that transcriptional inducers may have potential as novel mechanism-based drugs against metal overload in PD.
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40
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Mundhenk J, Fusi C, Kreutz MR. Caldendrin and Calneurons-EF-Hand CaM-Like Calcium Sensors With Unique Features and Specialized Neuronal Functions. Front Mol Neurosci 2019; 12:16. [PMID: 30787867 PMCID: PMC6372560 DOI: 10.3389/fnmol.2019.00016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/17/2019] [Indexed: 01/02/2023] Open
Abstract
The calmodulin (CaM)-like Ca2+-sensor proteins caldendrin, calneuron-1 and -2 are members of the neuronal calcium-binding protein (nCaBP)-family, a family that evolved relatively late during vertebrate evolution. All three proteins are abundant in brain but show a strikingly different subcellular localization. Whereas caldendrin is enriched in the postsynaptic density (PSD), calneuron-1 and -2 accumulate at the trans-Golgi-network (TGN). Caldendrin exhibit a unique bipartite structure with a basic and proline-rich N-terminus while calneurons are the only EF-Hand CaM-like transmembrane proteins. These uncommon structural features come along with highly specialized functions of calneurons in Golgi-to-plasma-membrane trafficking and for caldendrin in actin-remodeling in dendritic spine synapses. In this review article, we will provide a synthesis of available data on the structure and biophysical properties of all three proteins. We will then discuss their cellular function with special emphasis on synaptic neurotransmission. Finally, we will summarize the evidence for a role of these proteins in neuropsychiatric disorders.
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Affiliation(s)
- Jennifer Mundhenk
- RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Camilla Fusi
- RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Michael R Kreutz
- RG Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Leibniz Group "Dendritic Organelles and Synaptic Function", Center for Molecular Neurobiology, ZMNH, Hamburg, Germany
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41
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From membrane receptors to protein synthesis and actin cytoskeleton: Mechanisms underlying long lasting forms of synaptic plasticity. Semin Cell Dev Biol 2019; 95:120-129. [PMID: 30634048 DOI: 10.1016/j.semcdb.2019.01.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 12/13/2022]
Abstract
Synaptic plasticity, the activity dependent change in synaptic strength, forms the molecular foundation of learning and memory. Synaptic plasticity includes structural changes, with spines changing their size to accomodate insertion and removal of postynaptic receptors, which are correlated with functional changes. Of particular relevance for memory storage are the long lasting forms of synaptic plasticity which are protein synthesis dependent. Due to the importance of spine structural plasticity and protein synthesis, this review focuses on the signaling pathways that connect synaptic stimulation with regulation of protein synthesis and remodeling of the actin cytoskeleton. We also review computational models that implement novel aspects of molecular signaling in synaptic plasticity, such as the role of neuromodulators and spatial microdomains, as well as highlight the need for computational models that connect activation of memory kinases with spine actin dynamics.
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42
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Pangrsic T, Singer JH, Koschak A. Voltage-Gated Calcium Channels: Key Players in Sensory Coding in the Retina and the Inner Ear. Physiol Rev 2019; 98:2063-2096. [PMID: 30067155 DOI: 10.1152/physrev.00030.2017] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Calcium influx through voltage-gated Ca (CaV) channels is the first step in synaptic transmission. This review concerns CaV channels at ribbon synapses in primary sense organs and their specialization for efficient coding of stimuli in the physical environment. Specifically, we describe molecular, biochemical, and biophysical properties of the CaV channels in sensory receptor cells of the retina, cochlea, and vestibular apparatus, and we consider how such properties might change over the course of development and contribute to synaptic plasticity. We pay particular attention to factors affecting the spatial arrangement of CaV channels at presynaptic, ribbon-type active zones, because the spatial relationship between CaV channels and release sites has been shown to affect synapse function critically in a number of systems. Finally, we review identified synaptopathies affecting sensory systems and arising from dysfunction of L-type, CaV1.3, and CaV1.4 channels or their protein modulatory elements.
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Affiliation(s)
- Tina Pangrsic
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
| | - Joshua H Singer
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
| | - Alexandra Koschak
- Synaptic Physiology of Mammalian Vestibular Hair Cells Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen and Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine , Göttingen, Germany ; Department of Biology, University of Maryland , College Park, Maryland ; and Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck , Innsbruck , Austria
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43
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Basak R, Narayanan R. Active dendrites regulate the spatiotemporal spread of signaling microdomains. PLoS Comput Biol 2018; 14:e1006485. [PMID: 30383745 PMCID: PMC6233924 DOI: 10.1371/journal.pcbi.1006485] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 11/13/2018] [Accepted: 09/03/2018] [Indexed: 12/24/2022] Open
Abstract
Microdomains that emerge from spatially constricted spread of biochemical signaling components play a central role in several neuronal computations. Although dendrites, endowed with several voltage-gated ion channels, form a prominent structural substrate for microdomain physiology, it is not known if these channels regulate the spatiotemporal spread of signaling microdomains. Here, we employed a multiscale, morphologically realistic, conductance-based model of the hippocampal pyramidal neuron that accounted for experimental details of electrical and calcium-dependent biochemical signaling. We activated synaptic N-Methyl-d-Aspartate receptors through theta-burst stimulation (TBS) or pairing (TBP) and assessed microdomain propagation along a signaling pathway that included calmodulin, calcium/calmodulin-dependent protein kinase II (CaMKII) and protein phosphatase 1. We found that the spatiotemporal spread of the TBS-evoked microdomain in phosphorylated CaMKII (pCaMKII) was amplified in comparison to that of the corresponding calcium microdomain. Next, we assessed the role of two dendritically expressed inactivating channels, one restorative (A-type potassium) and another regenerative (T-type calcium), by systematically varying their conductances. Whereas A-type potassium channels suppressed the spread of pCaMKII microdomains by altering the voltage response to TBS, T-type calcium channels enhanced this spread by modulating TBS-induced calcium influx without changing the voltage. Finally, we explored cross-dependencies of these channels with other model components, and demonstrated the heavy mutual interdependence of several biophysical and biochemical properties in regulating microdomains and their spread. Our conclusions unveil a pivotal role for dendritic voltage-gated ion channels in actively amplifying or suppressing biochemical signals and their spatiotemporal spread, with critical implications for clustered synaptic plasticity, robust information transfer and efficient neural coding. The spatiotemporal spread of biochemical signals in neurons and other cells regulate signaling specificity, tuning of signal propagation, along with specificity and clustering of adaptive plasticity. Theoretical and experimental studies have demonstrated a critical role for cellular morphology and the topology of signaling networks in regulating this spread. In this study, we add a significantly complex dimension to this narrative by demonstrating that voltage-gated ion channels on the plasma membrane could actively amplify or suppress the strength and spread of downstream signaling components. Given the expression of different ion channels with wide-ranging heterogeneity in gating kinetics, localization and density, our results point to an increase in complexity of and degeneracy in signaling spread, and unveil a powerful mechanism for regulating biochemical-signaling pathways across different cell types.
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Affiliation(s)
- Reshma Basak
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
- * E-mail:
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44
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Filadi R, Basso E, Lefkimmiatis K, Pozzan T. Beyond Intracellular Signaling: The Ins and Outs of Second Messengers Microdomains. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 981:279-322. [PMID: 29594866 DOI: 10.1007/978-3-319-55858-5_12] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A typical characteristic of eukaryotic cells compared to prokaryotes is represented by the spatial heterogeneity of the different structural and functional components: for example, most of the genetic material is surrounded by a highly specific membrane structure (the nuclear membrane), continuous with, yet largely different from, the endoplasmic reticulum (ER); oxidative phosphorylation is carried out by organelles enclosed by a double membrane, the mitochondria; in addition, distinct domains, enriched in specific proteins, are present in the plasma membrane (PM) of most cells. Less obvious, but now generally accepted, is the notion that even the concentration of small molecules such as second messengers (Ca2+ and cAMP in particular) can be highly heterogeneous within cells. In the case of most organelles, the differences in the luminal levels of second messengers depend either on the existence on their membrane of proteins that allow the accumulation/release of the second messenger (e.g., in the case of Ca2+, pumps, exchangers or channels), or on the synthesis and degradation of the specific molecule within the lumen (the autonomous intramitochondrial cAMP system). It needs stressing that the existence of a surrounding membrane does not necessarily imply the existence of a gradient between the cytosol and the organelle lumen. For example, the nuclear membrane is highly permeable to both Ca2+ and cAMP (nuclear pores are permeable to solutes up to 50 kDa) and differences in [Ca2+] or [cAMP] between cytoplasm and nucleoplasm are not seen in steady state and only very transiently during cell activation. A similar situation has been observed, as far as Ca2+ is concerned, in peroxisomes.
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Affiliation(s)
- Riccardo Filadi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Emy Basso
- Institute of Neuroscience, Padova Section, National Research Council, Padova, Italy
| | - Konstantinos Lefkimmiatis
- Institute of Neuroscience, Padova Section, National Research Council, Padova, Italy
- Venetian Institute of Molecular Medicine, Padova, Italy
| | - Tullio Pozzan
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
- Institute of Neuroscience, Padova Section, National Research Council, Padova, Italy.
- Venetian Institute of Molecular Medicine, Padova, Italy.
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45
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Tran V, Stricker C. Diffusion of Ca 2+ from Small Boutons en Passant into the Axon Shapes AP-Evoked Ca 2+ Transients. Biophys J 2018; 115:1344-1356. [PMID: 30103908 DOI: 10.1016/j.bpj.2018.07.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/01/2018] [Accepted: 07/16/2018] [Indexed: 01/16/2023] Open
Abstract
Not only the amplitude but also the time course of a presynaptic Ca2+ transient determine multiple aspects of synaptic transmission. In small bouton-type synapses, the mechanisms underlying the Ca2+ decay kinetics have not been fully investigated. Here, factors that shape an action-potential-evoked Ca2+ transient were quantitatively studied in synaptic boutons of neocortical layer 5 pyramidal neurons. Ca2+ transients were measured with different concentrations of fluorescent Ca2+ indicators and analyzed based on a single-compartment model. We found a small endogenous Ca2+-binding ratio (7 ± 2) and a high activity of Ca2+ transporters (0.64 ± 0.03 ms-1), both of which enable rapid clearance of Ca2+ from the boutons. However, contrary to predictions of the single-compartment model, the decay time course of the measured Ca2+ transients was biexponential and became prolonged during repetitive stimulation. Measurements of [Ca2+]i along the adjoining axon, together with an experimentally constrained model, showed that the initial fast decay of the Ca2+ transients predominantly arose from the diffusion of Ca2+ from the boutons into the axon. Therefore, for small boutons en passant, factors like terminal volume, axon diameter, and the concentration of mobile Ca2+-binding molecules are critical determinants of Ca2+ dynamics and thus Ca2+-dependent processes, including short-term synaptic plasticity.
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Affiliation(s)
- Van Tran
- Eccles Institute of Neuroscience, JCSMR.
| | - Christian Stricker
- Eccles Institute of Neuroscience, JCSMR; ANU Medical School, ANU, Acton, Australian Capital Territory, Australia
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46
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Singh M, Lujan B, Renden R. Presynaptic GCaMP expression decreases vesicle release probability at the calyx of Held. Synapse 2018; 72:e22040. [PMID: 29935099 PMCID: PMC6186185 DOI: 10.1002/syn.22040] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 12/15/2022]
Abstract
Synaptic vesicle (SV) exocytosis is intimately dependent on free local Ca2+ near active zones. Genetically encoded calcium indicators (GECIs) have become an indispensable tool to monitor calcium dynamics during physiological responses, and they are widely used as a proxy to monitor activity in neuronal ensembles and at synaptic terminals. However, GECIs’ ability to bind Ca2+ at physiologically relevant concentration makes them strong candidates to affect calcium homeostasis and alter synaptic transmission by exogenously increasing Ca2+ buffering. In the present study, we show that genetically expressed GCaMP6m modulates SV release probability at the mouse calyx of Held synapse. GCaMP6m expression for approximately three weeks decreased initial SV release for both low‐frequency stimulation and high‐frequency stimulation trains, and slowed presynaptic short‐term depression. However, GCaMP6m does not affect quantal events during spontaneous activity at this synapse. This study emphasizes the careful use of GECIs as monitors of neuronal activity and inspects the role of these transgenic indicators which may alter calcium‐dependent physiological responses.
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Affiliation(s)
- Mahendra Singh
- Department of Physiology and Cell Biology, University of Nevada, Reno, Nevada, 89557
| | - Brendan Lujan
- Department of Physiology and Cell Biology, University of Nevada, Reno, Nevada, 89557.,Currently at Vollum Institute, Oregon Health and Science University, Portland, Oregon
| | - Robert Renden
- Department of Physiology and Cell Biology, University of Nevada, Reno, Nevada, 89557
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47
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Suppressed Calbindin Levels in Hippocampal Excitatory Neurons Mediate Stress-Induced Memory Loss. Cell Rep 2018; 21:891-900. [PMID: 29069596 DOI: 10.1016/j.celrep.2017.10.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/31/2017] [Accepted: 10/02/2017] [Indexed: 01/01/2023] Open
Abstract
Calbindin modulates intracellular Ca2+ dynamics and synaptic plasticity. Reduction of hippocampal calbindin levels has been implicated in early-life stress-related cognitive disorders, but it remains unclear how calbindin in distinct populations of hippocampal neurons contributes to stress-induced memory loss. Here we report that early-life stress suppressed calbindin levels in CA1 and dentate gyrus (DG) neurons, and calbindin knockdown in adult CA1 or DG excitatory neurons mimicked early-life stress-induced memory loss. In contrast, calbindin knockdown in CA1 interneurons preserved long-term memory even after an acute stress challenge. These results indicate that the dysregulation of calbindin in hippocampal excitatory, but not inhibitory, neurons conveys susceptibility to stress-induced memory deficits. Moreover, calbindin levels were downregulated by early-life stress through the corticotropin-releasing hormone receptor 1-nectin3 pathway, which in turn reduced inositol monophosphatase levels. Our findings highlight calbindin as a molecular target of early-life stress and an essential substrate for memory.
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48
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Lu Y, Truman W, Liu X, Bethke G, Zhou M, Myers CL, Katagiri F, Glazebrook J. Different Modes of Negative Regulation of Plant Immunity by Calmodulin-Related Genes. PLANT PHYSIOLOGY 2018; 176:3046-3061. [PMID: 29449432 PMCID: PMC5884591 DOI: 10.1104/pp.17.01209] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 02/06/2018] [Indexed: 05/23/2023]
Abstract
Plant immune responses activated through the perception of microbe-associated molecular patterns, leading to pattern-triggered immunity, are tightly regulated. This results in low immune responses in the absence of pathogens and a rapid return to the resting state following an activation event. Here, we show that two CALMODULIN-LIKE genes, CML46 and CML47, negatively regulate salicylic acid accumulation and immunity in Arabidopsis (Arabidopsis thaliana). The double mutant cml46 cml47 is highly resistant to the pathogen Pseudomonas syringae pv maculicola (Pma). The effects of cml46 cml47 on Pma growth are genetically additive to that of cbp60a, a known negative regulator in the CALMODULIN-BINDING PROTEIN60 (CBP60) family. Transcriptome profiling revealed the effects of cbp60a and cml46 cml47 on both common and separate sets of genes, with the majorities of these differentially expressed genes being Pma responsive. CBP60g, a positive regulator of immunity in the CBP60 family, was found to be transcriptionally regulated by CBP60a, CML46, and CML47 Analysis of the flg22-induced mRNA levels of CBP60g in cbp60a and cml46 cml47 revealed that cml46 cml47 plants have higher induced expression while cbp60a plants retain elevated levels longer than wild-type plants. Assays for the effect of flg22 treatment on Pma growth showed that the effect is stronger in cml46 cml47 plants and lasts longer in cbp60a plants. Thus, the expression pattern of CBP60g is reflected in flg22-induced resistance to Pma.
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Affiliation(s)
- You Lu
- Department of Plant and Microbial Biology and Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, Saint Paul, Minnesota 55108
| | - William Truman
- Department of Plant and Microbial Biology and Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, Saint Paul, Minnesota 55108
| | - Xiaotong Liu
- Department of Computer Science and Engineering and Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, Minneapolis, Minnesota 55455
- Graduate Program in Bioinformatics and Computational Biology, University of Minnesota, Twin Cities, Minneapolis, Minnesota 55455
| | - Gerit Bethke
- Department of Plant and Microbial Biology and Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, Saint Paul, Minnesota 55108
| | - Man Zhou
- Department of Plant and Microbial Biology and Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, Saint Paul, Minnesota 55108
| | - Chad L Myers
- Department of Computer Science and Engineering and Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, Minneapolis, Minnesota 55455
| | - Fumiaki Katagiri
- Department of Plant and Microbial Biology and Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, Saint Paul, Minnesota 55108
| | - Jane Glazebrook
- Department of Plant and Microbial Biology and Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, Saint Paul, Minnesota 55108
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49
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Zheng K, Jensen TP, Rusakov DA. Monitoring intracellular nanomolar calcium using fluorescence lifetime imaging. Nat Protoc 2018; 13:581-597. [PMID: 29470463 DOI: 10.1038/nprot.2017.154] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nanomolar-range fluctuations of intracellular [Ca2+] are critical for brain cell function but remain difficult to measure. We have advanced a microscopy technique to monitor intracellular [Ca2+] in individual cells in acute brain slices (also applicable in vivo) using fluorescence lifetime imaging (FLIM) of the Ca2+-sensitive fluorescent indicator Oregon Green BAPTA1 (OGB-1). The OGB-1 fluorescence lifetime is sensitive to [Ca2+] within the 10-500 nM range but not to other factors such as viscosity, temperature, or pH. This protocol describes the requirements, setup, and calibration of the FLIM system required for OGB-1 imaging. We provide a step-by-step procedure for whole-cell OGB-1 loading and two-photon FLIM. We also describe how to analyze the obtained FLIM data using total photon count and gated-intensity record, a ratiometric photon-counting approach that provides a highly improved signal-to-noise ratio and greater sensitivity of absolute [Ca2+] readout. We demonstrate our technique in nerve cells in situ, and it is adaptable to other cell types and fluorescent indicators. This protocol requires a basic understanding of FLIM and experience in single-cell electrophysiology and cell imaging. Setting up the FLIM system takes ∼2 d, and OGB-1 loading, imaging, and data analysis take 2 d.
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Affiliation(s)
- Kaiyu Zheng
- UCL Institute of Neurology, University College London, London, UK
| | - Thomas P Jensen
- UCL Institute of Neurology, University College London, London, UK
| | - Dmitri A Rusakov
- UCL Institute of Neurology, University College London, London, UK
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50
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Mikhaylova M, Bär J, van Bommel B, Schätzle P, YuanXiang P, Raman R, Hradsky J, Konietzny A, Loktionov EY, Reddy PP, Lopez-Rojas J, Spilker C, Kobler O, Raza SA, Stork O, Hoogenraad CC, Kreutz MR. Caldendrin Directly Couples Postsynaptic Calcium Signals to Actin Remodeling in Dendritic Spines. Neuron 2018; 97:1110-1125.e14. [PMID: 29478916 DOI: 10.1016/j.neuron.2018.01.046] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 12/18/2017] [Accepted: 01/26/2018] [Indexed: 11/19/2022]
Abstract
Compartmentalization of calcium-dependent plasticity allows for rapid actin remodeling in dendritic spines. However, molecular mechanisms for the spatio-temporal regulation of filamentous actin (F-actin) dynamics by spinous Ca2+-transients are still poorly defined. We show that the postsynaptic Ca2+ sensor caldendrin orchestrates nano-domain actin dynamics that are essential for actin remodeling in the early phase of long-term potentiation (LTP). Steep elevation in spinous [Ca2+]i disrupts an intramolecular interaction of caldendrin and allows cortactin binding. The fast on and slow off rate of this interaction keeps cortactin in an active conformation, and protects F-actin at the spine base against cofilin-induced severing. Caldendrin gene knockout results in higher synaptic actin turnover, altered nanoscale organization of spinous F-actin, defects in structural spine plasticity, LTP, and hippocampus-dependent learning. Collectively, the data indicate that caldendrin-cortactin directly couple [Ca2+]i to preserve a minimal F-actin pool that is required for actin remodeling in the early phase of LTP.
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Affiliation(s)
- Marina Mikhaylova
- Emmy Noether Group "Neuronal Protein Transport," Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany; RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg 39118, Germany; Cell Biology, Faculty of Science, Utrecht University, Utrecht 3584 CH, the Netherlands.
| | - Julia Bär
- Emmy Noether Group "Neuronal Protein Transport," Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany; RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg 39118, Germany
| | - Bas van Bommel
- Emmy Noether Group "Neuronal Protein Transport," Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
| | - Philipp Schätzle
- Cell Biology, Faculty of Science, Utrecht University, Utrecht 3584 CH, the Netherlands
| | - PingAn YuanXiang
- RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg 39118, Germany
| | - Rajeev Raman
- RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg 39118, Germany
| | - Johannes Hradsky
- RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg 39118, Germany
| | - Anja Konietzny
- Emmy Noether Group "Neuronal Protein Transport," Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany
| | - Egor Y Loktionov
- State Lab for Photon Energetics, Bauman Moscow State University, Moscow 105005, Russia
| | | | - Jeffrey Lopez-Rojas
- RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg 39118, Germany
| | - Christina Spilker
- RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg 39118, Germany
| | - Oliver Kobler
- Combinatorial Neuroimaging Core Facility (CNI), Leibniz Institute for Neurobiology, Magdeburg 39118, Germany
| | - Syed Ahsan Raza
- Institute of Biology, Otto von Guericke University, Magdeburg 39120, Germany
| | - Oliver Stork
- Institute of Biology, Otto von Guericke University, Magdeburg 39120, Germany
| | - Casper C Hoogenraad
- Cell Biology, Faculty of Science, Utrecht University, Utrecht 3584 CH, the Netherlands
| | - Michael R Kreutz
- RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg 39118, Germany; Leibniz Group "Dendritic Organelles and Synaptic Function," Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg 20251, Germany.
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