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Michálek O, King GF, Pekár S. Prey specificity of predatory venoms. Biol Rev Camb Philos Soc 2024. [PMID: 38991997 DOI: 10.1111/brv.13120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 07/01/2024] [Accepted: 07/03/2024] [Indexed: 07/13/2024]
Abstract
Venom represents a key adaptation of many venomous predators, allowing them to immobilise prey quickly through chemical rather than physical warfare. Evolutionary arms races between prey and a predator are believed to be the main factor influencing the potency and composition of predatory venoms. Predators with narrowly restricted diets are expected to evolve specifically potent venom towards their focal prey, with lower efficacy on alternative prey. Here, we evaluate hypotheses on the evolution of prey-specific venom, focusing on the effect of restricted diet, prey defences, and prey resistance. Prey specificity as a potential evolutionary dead end is also discussed. We then provide an overview of the current knowledge on venom prey specificity, with emphasis on snakes, cone snails, and spiders. As the current evidence for venom prey specificity is still quite limited, we also overview the best approaches and methods for its investigation and provide a brief summary of potential model groups. Finally, possible applications of prey-specific toxins are discussed.
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Affiliation(s)
- Ondřej Michálek
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, Brno, 611 37, Czech Republic
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, 4072, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St. Lucia, Queensland, 4072, Australia
| | - Stano Pekár
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, Brno, 611 37, Czech Republic
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2
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Murphy EA, Kleiner FH, Helliwell KE, Wheeler GL. Channels of Evolution: Unveiling Evolutionary Patterns in Diatom Ca 2+ Signalling. PLANTS (BASEL, SWITZERLAND) 2024; 13:1207. [PMID: 38732422 PMCID: PMC11085791 DOI: 10.3390/plants13091207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/09/2024] [Accepted: 04/15/2024] [Indexed: 05/13/2024]
Abstract
Diatoms are important primary producers in marine and freshwater environments, but little is known about the signalling mechanisms they use to detect changes in their environment. All eukaryotic organisms use Ca2+ signalling to perceive and respond to environmental stimuli, employing a range of Ca2+-permeable ion channels to facilitate the movement of Ca2+ across cellular membranes. We investigated the distribution of different families of Ca2+ channels in diatom genomes, with comparison to other members of the stramenopile lineage. The four-domain voltage-gated Ca2+ channels (Cav) are present in some centric diatoms but almost completely absent in pennate diatoms, whereas single-domain voltage-gated EukCatA channels were found in all diatoms. Glutamate receptors (GLRs) and pentameric ligand-gated ion channels (pLGICs) also appear to have been lost in several pennate species. Transient receptor potential (TRP) channels are present in all diatoms, but have not undergone the significant expansion seen in brown algae. All diatom species analysed lacked the mitochondrial uniporter (MCU), a highly conserved channel type found in many eukaryotes, including several stramenopile lineages. These results highlight the unique Ca2+-signalling toolkit of diatoms and indicate that evolutionary gains or losses of different Ca2+ channels may contribute to differences in cellular-signalling mechanisms between species.
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Affiliation(s)
- Eleanor A. Murphy
- Marine Biological Association, Plymouth PL1 2PB, UK (K.E.H.)
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | | | - Katherine E. Helliwell
- Marine Biological Association, Plymouth PL1 2PB, UK (K.E.H.)
- Department of Biosciences, University of Exeter, Exeter EX4 4QD, UK
| | - Glen L. Wheeler
- Marine Biological Association, Plymouth PL1 2PB, UK (K.E.H.)
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3
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Pérez-Gordones MC, Ramírez-Iglesias JR, Benaim G, Mendoza M. Molecular, immunological, and physiological evidences of a sphingosine-activated plasma membrane Ca 2+-channel in Trypanosoma equiperdum. Parasitol Res 2024; 123:166. [PMID: 38506929 DOI: 10.1007/s00436-024-08188-z] [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: 10/18/2023] [Accepted: 03/14/2024] [Indexed: 03/22/2024]
Abstract
The hemoparasite Trypanosoma equiperdum belongs to the Trypanozoon subgenus and includes several species that are pathogenic to animals and humans in tropical and subtropical areas across the world. As with all eukaryotic organisms, Ca2+ is essential for these parasites to perform cellular processes thus ensuring their survival across their life cycle. Despite the established paradigm to study proteins related to Ca2+ homeostasis as potential drug targets, so far little is known about Ca2+ entry into trypanosomes. Therefore, in the present study, the presence of a plasma membrane Ca2+-channel in T. equiperdum (TeCC), activated by sphingosine and inhibited by verapamil, is described. The TeCC was cloned and analyzed using bioinformatic resources, which confirmed the presence of several domains, motifs, and a topology similar to the Ca2+ channels found in higher eukaryotes. Biochemical and confocal microscopy assays using antibodies raised against an internal region of human L-type Ca2+ channels indicate the presence of a protein with similar predicted molar mass to the sequence analyzed, located at the plasma membrane of T. equiperdum. Physiological assays based on Fura-2 signals and Mn2+ quenching performed on whole parasites showed a unidirectional Ca2+ entry, which is activated by sphingosine and blocked by verapamil, with the distinctive feature of insensitivity to nifedipine and Bay K 8644. This suggests a second Ca2+ entry for T. equiperdum, different from the store-operated Ca2+ entry (SOCE) previously described. Moreover, the evidence presented here for the TeCC indicates molecular and pharmacological differences with their mammal counterparts, which deserve further studies to evaluate the potential of this channel as a drug target.
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Affiliation(s)
- M C Pérez-Gordones
- Instituto de Biología Experimental (IBE), Universidad Central de Venezuela (UCV), Caracas, Venezuela.
| | - J R Ramírez-Iglesias
- Group of Emerging Diseases, Epidemiology & Biodiversity, Master School of Biomedicine, Health Sciences Faculty, Universidad Internacional SEK (UISEK), Quito, Ecuador
| | - G Benaim
- Instituto de Biología Experimental (IBE), Universidad Central de Venezuela (UCV), Caracas, Venezuela
- Instituto de Estudios Avanzados (IDEA), Caracas, Venezuela
| | - M Mendoza
- Centro de Estudios Biomédicos y Veterinarios, Instituto de Estudios Científicos y Tecnológicos (IDECYT), Universidad Nacional Experimental Simón Rodríguez, Caracas, Venezuela
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4
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Harracksingh AN, Singh A, Mayorova T, Bejoy B, Hornbeck J, Elkhatib W, McEdwards G, Gauberg J, Taha ARW, Islam IM, Erclik T, Currie MA, Noyes M, Senatore A. The binding of Mint/X11 PDZ domains to Ca V 2 calcium channels predates bilaterian animals. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.26.582151. [PMID: 38463976 PMCID: PMC10925089 DOI: 10.1101/2024.02.26.582151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
PDZ domain mediated interactions with voltage-gated calcium (Ca V ) channel C-termini play important roles in localizing and compartmentalizing membrane Ca 2+ signaling. The first such interaction discovered was between the neuronal multi-domain protein Mint-1, and the presynaptc calcium channel Ca V 2.2 in mammals. Although the physiological significance of this interaction is unclear, its occurrence in vertebrates and bilaterian invertebrates suggests important and conserved functions. In this study, we explore the evolutionary origins of Mint and its interaction with Ca V 2 channels. Phylogenetic and structural in silico analyses revealed that Mint is an animal-specific gene, like Ca V 2 channels, which bears a highly divergent N-terminus but strongly conserved C-terminus comprised of a phosphotyrosine binding domain, two tandem PDZ domains (PDZ-1 and PDZ-2), and a C-terminal auto-inhibitory element that binds and inhibits PDZ-1. Also deeply conserved are other Mint interacting proteins, namely amyloid precursor and related proteins, presenilins, neurexin, as well as CASK and Veli which form a tripartite complex with Mint in bilaterians. Through yeast 2-hybrid and bacterial 2-hybrid experiments, we show that Mint and Ca V 2 channels from cnidarians and placozoans interact in vitro , and in situ hybridization revealed co-expression of corresponding transcripts in dissociated neurons from the cnidarian Nematostella vectensis . Unexpectedly, the Mint orthologue from the ctenophore Hormiphora californiensis was able to strongly bind the divergent C-terminal ligands of cnidarian and placozoan Ca V 2 channels, despite neither the ctenophore Mint, nor the placozoan and cnidarian orthologues, binding the ctenophore Ca V 2 channel C-terminus. Altogether, our analyses provide a model for the emergence of this interaction in early animals first via adoption of a PDZ ligand by Ca V 2 channels, followed by sequence changes in the ligand that caused a modality switch for binding to Mint.
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5
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Sylvain-Bonfanti L, Page J, Arbelet-Bonnin D, Meimoun P, Grésillon É, Bouteau F, Laurenti P. [Anaesthesia, a process common to all living organisms]. Med Sci (Paris) 2023; 39:738-743. [PMID: 37943134 DOI: 10.1051/medsci/2023123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023] Open
Abstract
Because of their interest in medicine, most studies of anaesthesia focus on the nervous system of metazoans, and the fact that any life form can be anaesthetised is often underlooked. If electrical signalling is an essential phenomenon for the success of animals, it appears to be widespread beyond metazoans. Indeed, anaesthesia targets Na+/Ca2+ voltage-gated channels that exist in a wide variety of species and originate from ancestral channels that predate eukaryotes in the course of evolution. The fact that the anaesthetic capacity that leads to loss of sensitivity is common to all phyla may lead to two hypotheses: to be investigated is the evolutionary maintenance of the ability to be anaesthetised due to an adaptive advantage or to a simple intrinsic defect in ion channels? The study of anaesthesia in organisms phylogenetically distant from animals opens up promising prospects for the discovery of new anaesthetic treatments. Moreover, it should also lead to a better understanding of a still poorly understood phenomenon that yet unifies all living organisms. We hope that this new understanding of the unity of life will help humans to assume their responsibilities towards all species, at a time when we are threatening biodiversity with mass extinction.
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Affiliation(s)
- Lucia Sylvain-Bonfanti
- Université Paris-Cité, laboratoire interdisciplinaire des énergies de demain (LIED UMR 8236), Paris, France - Université Paris-Cité, laboratoire dynamiques sociales et recomposition des espaces (LADYSS UMR 7533), Paris, France
| | - Julien Page
- Université Paris-Cité, laboratoire interdisciplinaire des énergies de demain (LIED UMR 8236), Paris, France
| | - Delphine Arbelet-Bonnin
- Université Paris-Cité, laboratoire interdisciplinaire des énergies de demain (LIED UMR 8236), Paris, France
| | - Patrice Meimoun
- Université Paris-Cité, laboratoire interdisciplinaire des énergies de demain (LIED UMR 8236), Paris, France - Sorbonne université, Paris, France
| | - Étienne Grésillon
- Université Paris-Cité, laboratoire dynamiques sociales et recomposition des espaces (LADYSS UMR 7533), Paris, France
| | - François Bouteau
- Université Paris-Cité, laboratoire interdisciplinaire des énergies de demain (LIED UMR 8236), Paris, France
| | - Patrick Laurenti
- Université Paris-Cité, laboratoire interdisciplinaire des énergies de demain (LIED UMR 8236), Paris, France
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6
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Elkhatib W, Yanez-Guerra LA, Mayorova TD, Currie MA, Singh A, Perera M, Gauberg J, Senatore A. Function and phylogeny support the independent evolution of an ASIC-like Deg/ENaC channel in the Placozoa. Commun Biol 2023; 6:951. [PMID: 37723223 PMCID: PMC10507113 DOI: 10.1038/s42003-023-05312-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 09/01/2023] [Indexed: 09/20/2023] Open
Abstract
ASIC channels are bilaterian proton-gated sodium channels belonging to the large and functionally-diverse Deg/ENaC family that also includes peptide- and mechanically-gated channels. Here, we report that the non-bilaterian invertebrate Trichoplax adhaerens possesses a proton-activated Deg/ENaC channel, TadNaC2, with a unique combination of biophysical features including tachyphylaxis like ASIC1a, reduced proton sensitivity like ASIC2a, biphasic macroscopic currents like ASIC3, as well as low sensitivity to the Deg/ENaC channel blocker amiloride and Ca2+ ions. Structural modeling and mutation analyses reveal that TadNaC2 proton gating is different from ASIC channels, lacking key molecular determinants, and involving unique residues within the palm and finger regions. Phylogenetic analysis reveals that a monophyletic clade of T. adhaerens Deg/ENaC channels, which includes TadNaC2, is phylogenetically distinct from ASIC channels, instead forming a clade with BASIC channels. Altogether, this work suggests that ASIC-like channels evolved independently in T. adhaerens and its phylum Placozoa. Our phylogenetic analysis also identifies several clades of uncharacterized metazoan Deg/ENaC channels, and provides phylogenetic evidence for the existence of Deg/ENaC channels outside of Metazoa, present in the gene data of select unicellular heterokont and filasterea-related species.
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Affiliation(s)
- Wassim Elkhatib
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Luis A Yanez-Guerra
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, England
| | | | - Mark A Currie
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Anhadvir Singh
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Maria Perera
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Julia Gauberg
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON, L5L 1C6, Canada.
- Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada.
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7
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Sanyal SK, Awasthi M, Ranjan P, Sharma S, Pandey GK, Kateriya S. Characterization of Chlamydomonas voltage-gated calcium channel and its interaction with photoreceptor support VGCC modulated photobehavioral response in the green alga. Int J Biol Macromol 2023; 245:125492. [PMID: 37343610 DOI: 10.1016/j.ijbiomac.2023.125492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 06/09/2023] [Accepted: 06/18/2023] [Indexed: 06/23/2023]
Abstract
Calcium (Ca2+) signaling plays a major role in regulating multiple processes in living cells. The photoreceptor potential in Chlamydomonas triggers the generation of all or no flagellar Ca2+ currents that cause membrane depolarization across the eyespot and flagella. Modulation in membrane potential causes changes in the flagellar waveform, and hence, alters the beating patterns of Chlamydomonas flagella. The rhodopsin-mediated eyespot membrane potential is generated by the photoreceptor Ca2+ current or P-current however, the flagellar Ca2+ currents are mediated by unidentified voltage-gated calcium (VGCC or CaV) and potassium channels (VGKC). The voltage-gated ion channel that associates with ChRs to generate Ca2+ influx across the flagella and its cellular distribution has not yet been identified. Here, we identified putative VGCCs from algae and predicted their novel properties through insilico analysis. We further present experimental evidence on Chlamydomonas reinhardtii VGCCs to predict their novel physiological roles. Our experimental evidences showed that CrVGCC4 localizes to the eyespot and flagella of Chlamydomonas and associates with channelrhodopsins (ChRs). Further in silico interactome analysis of CrVGCCs suggested that they putatively interact with photoreceptor proteins, calcium signaling, and intraflagellar transport components. Expression analysis indicated that these VGCCs and their putative interactors can be perturbed by light stimuli. Collectively, our data suggest that VGCCs in general, and VGCC4 in particular, might be involved in the regulation of the photobehavioral response of Chlamydomonas.
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Affiliation(s)
- Sibaji K Sanyal
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Mayanka Awasthi
- Department of Biochemistry, the University of Delhi South Campus, New Delhi 110021, India
| | - Peeyush Ranjan
- Department of Biochemistry, the University of Delhi South Campus, New Delhi 110021, India
| | - Sunita Sharma
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Girdhar K Pandey
- Department of Plant Molecular Biology, the University of Delhi South Campus, New Delhi 110021, India.
| | - Suneel Kateriya
- Laboratory of Optobiotechnology, School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India; Department of Biochemistry, the University of Delhi South Campus, New Delhi 110021, India.
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8
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Telesh IV, Skarlato SO. Harmful Blooms of Potentially Toxic Dinoflagellates in the Baltic Sea: Ecological, Cellular, and Molecular Background. RUSS J ECOL+ 2022. [DOI: 10.1134/s1067413622060157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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9
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Gauberg J, Elkhatib W, Smith CL, Singh A, Senatore A. Divergent Ca 2+/calmodulin feedback regulation of Ca V1 and Ca V2 voltage-gated calcium channels evolved in the common ancestor of Placozoa and Bilateria. J Biol Chem 2022; 298:101741. [PMID: 35182524 PMCID: PMC8980814 DOI: 10.1016/j.jbc.2022.101741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 02/10/2022] [Accepted: 02/13/2022] [Indexed: 11/04/2022] Open
Abstract
CaV1 and CaV2 voltage-gated calcium channels evolved from an ancestral CaV1/2 channel via gene duplication somewhere near the stem animal lineage. The divergence of these channel types led to distinguishing functional properties that are conserved among vertebrates and bilaterian invertebrates and contribute to their unique cellular roles. One key difference pertains to their regulation by calmodulin (CaM), wherein bilaterian CaV1 channels are uniquely subject to pronounced, buffer-resistant Ca2+/CaM-dependent inactivation, permitting negative feedback regulation of calcium influx in response to local cytoplasmic Ca2+ rises. Early diverging, nonbilaterian invertebrates also possess CaV1 and CaV2 channels, but it is unclear whether they share these conserved functional features. The most divergent animals to possess both CaV1 and CaV2 channels are placozoans such as Trichoplax adhaerens, which separated from other animals over 600 million years ago shortly after their emergence. Hence, placozoans can provide important insights into the early evolution of CaV1 and CaV2 channels. Here, we build upon previous characterization of Trichoplax CaV channels by determining the cellular expression and ion-conducting properties of the CaV1 channel orthologue, TCaV1. We show that TCaV1 is expressed in neuroendocrine-like gland cells and contractile dorsal epithelial cells. In vitro, this channel conducts dihydropyridine-insensitive, high-voltage–activated Ca2+ currents with kinetics resembling those of rat CaV1.2 but with left-shifted voltage sensitivity for activation and inactivation. Interestingly, TCaV1, but not TCaV2, exhibits buffer-resistant Ca2+/CaM-dependent inactivation, indicating that this functional divergence evolved prior to the emergence of bilaterian animals and may have contributed to their unique adaptation for cytoplasmic Ca2+ signaling within various cellular contexts.
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Affiliation(s)
- Julia Gauberg
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Wassim Elkhatib
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Carolyn L Smith
- NINDS, National Institutes of Health, Bethesda Maryland, 20892 USA
| | - Anhadvir Singh
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada.
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10
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Zhuo J, Gill JP, Jansen ED, Jenkins MW, Chiel HJ. Use of an invertebrate animal model ( Aplysia californica) to develop novel neural interfaces for neuromodulation. Front Neurosci 2022; 16:1080027. [PMID: 36620467 PMCID: PMC9813496 DOI: 10.3389/fnins.2022.1080027] [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: 10/25/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022] Open
Abstract
New tools for monitoring and manipulating neural activity have been developed with steadily improving functionality, specificity, and reliability, which are critical both for mapping neural circuits and treating neurological diseases. This review focuses on the use of an invertebrate animal, the marine mollusk Aplysia californica, in the development of novel neurotechniques. We review the basic physiological properties of Aplysia neurons and discuss the specific aspects that make it advantageous for developing novel neural interfaces: First, Aplysia nerves consist only of unmyelinated axons with various diameters, providing a particularly useful model of the unmyelinated C fibers in vertebrates that are known to carry important sensory information, including those that signal pain. Second, Aplysia's neural tissues can last for a long period in an ex vivo experimental setup. This allows comprehensive tests such as the exploration of parameter space on the same nerve to avoid variability between animals and minimize animal use. Third, nerves in large Aplysia can be many centimeters in length, making it possible to easily discriminate axons with different diameters based on their conduction velocities. Aplysia nerves are a particularly good approximation of the unmyelinated C fibers, which are hard to stimulate, record, and differentiate from other nerve fibers in vertebrate animal models using epineural electrodes. Fourth, neurons in Aplysia are large, uniquely identifiable, and electrically compact. For decades, researchers have used Aplysia for the development of many novel neurotechnologies. Examples include high-frequency alternating current (HFAC), focused ultrasound (FUS), optical neural stimulation, recording, and inhibition, microelectrode arrays, diamond electrodes, carbon fiber microelectrodes, microscopic magnetic stimulation and magnetic resonance electrical impedance tomography (MREIT). We also review a specific example that illustrates the power of Aplysia for accelerating technology development: selective infrared neural inhibition of small-diameter unmyelinated axons, which may lead to a translationally useful treatment in the future. Generally, Aplysia is suitable for testing modalities whose mechanism involves basic biophysics that is likely to be similar across species. As a tractable experimental system, Aplysia californica can help the rapid development of novel neuromodulation technologies.
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Affiliation(s)
- Junqi Zhuo
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Jeffrey P Gill
- Department of Biology, Case Western Reserve University, Cleveland, OH, United States
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States.,Biophotonics Center, Vanderbilt University, Nashville, TN, United States.,Department of Neurological Surgery, Vanderbilt University, Nashville, TN, United States
| | - Michael W Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States.,Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
| | - Hillel J Chiel
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States.,Department of Biology, Case Western Reserve University, Cleveland, OH, United States.,Department of Neurosciences, Case Western Reserve University, Cleveland, OH, United States
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11
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Gauberg J, Abdallah S, Elkhatib W, Harracksingh AN, Piekut T, Stanley EF, Senatore A. Conserved biophysical features of the Ca V2 presynaptic Ca 2+ channel homologue from the early-diverging animal Trichoplax adhaerens. J Biol Chem 2020; 295:18553-18578. [PMID: 33097592 PMCID: PMC7939481 DOI: 10.1074/jbc.ra120.015725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/21/2020] [Indexed: 12/20/2022] Open
Abstract
The dominant role of CaV2 voltage-gated calcium channels for driving neurotransmitter release is broadly conserved. Given the overlapping functional properties of CaV2 and CaV1 channels, and less so CaV3 channels, it is unclear why there have not been major shifts toward dependence on other CaV channels for synaptic transmission. Here, we provide a structural and functional profile of the CaV2 channel cloned from the early-diverging animal Trichoplax adhaerens, which lacks a nervous system but possesses single gene homologues for CaV1-CaV3 channels. Remarkably, the highly divergent channel possesses similar features as human CaV2.1 and other CaV2 channels, including high voltage-activated currents that are larger in external Ba2+ than in Ca2+; voltage-dependent kinetics of activation, inactivation, and deactivation; and bimodal recovery from inactivation. Altogether, the functional profile of Trichoplax CaV2 suggests that the core features of presynaptic CaV2 channels were established early during animal evolution, after CaV1 and CaV2 channels emerged via proposed gene duplication from an ancestral CaV1/2 type channel. The Trichoplax channel was relatively insensitive to mammalian CaV2 channel blockers ω-agatoxin-IVA and ω-conotoxin-GVIA and to metal cation blockers Cd2+ and Ni2+ Also absent was the capacity for voltage-dependent G-protein inhibition by co-expressed Trichoplax Gβγ subunits, which nevertheless inhibited the human CaV2.1 channel, suggesting that this modulatory capacity evolved via changes in channel sequence/structure, and not G proteins. Last, the Trichoplax channel was immunolocalized in cells that express an endomorphin-like peptide implicated in cell signaling and locomotive behavior and other likely secretory cells, suggesting contributions to regulated exocytosis.
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Affiliation(s)
- Julia Gauberg
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Salsabil Abdallah
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Wassim Elkhatib
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Alicia N Harracksingh
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Thomas Piekut
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Elise F Stanley
- Laboratory of Synaptic Transmission, Krembil Research Institute, Toronto, Ontario, Canada
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada.
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12
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Are antibacterial effects of non-antibiotic drugs random or purposeful because of a common evolutionary origin of bacterial and mammalian targets? Infection 2020; 49:569-589. [PMID: 33325009 PMCID: PMC7737717 DOI: 10.1007/s15010-020-01547-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 10/28/2020] [Indexed: 01/09/2023]
Abstract
Purpose Advances in structural biology, genetics, bioinformatics, etc. resulted in the availability of an enormous pool of information enabling the analysis of the ancestry of pro- and eukaryotic genes and proteins. Methods This review summarizes findings of structural and/or functional homologies of pro- and eukaryotic enzymes catalysing analogous biological reactions because of their highly conserved active centres so that non-antibiotics interacted with bacterial targets. Results Protease inhibitors such as staurosporine or camostat inhibited bacterial serine/threonine or serine/tyrosine protein kinases, serine/threonine phosphatases, and serine/threonine kinases, to which penicillin-binding-proteins are linked, so that these drugs synergized with β-lactams, reverted aminoglycoside-resistance and attenuated bacterial virulence. Calcium antagonists such as nitrendipine or verapamil blocked not only prokaryotic ion channels but interacted with negatively charged bacterial cell membranes thus disrupting membrane energetics and inducing membrane stress response resulting in inhibition of P-glycoprotein such as bacterial pumps thus improving anti-mycobacterial activities of rifampicin, tetracycline, fluoroquinolones, bedaquilin and imipenem-activity against Acinetobacter spp. Ciclosporine and tacrolimus attenuated bacterial virulence. ACE-inhibitors like captopril interacted with metallo-β-lactamases thus reverting carbapenem-resistance; prokaryotic carbonic anhydrases were inhibited as well resulting in growth impairment. In general, non-antibiotics exerted weak antibacterial activities on their own but synergized with antibiotics, and/or reverted resistance and/or attenuated virulence. Conclusions Data summarized in this review support the theory that prokaryotic proteins represent targets for non-antibiotics because of a common evolutionary origin of bacterial- and mammalian targets resulting in highly conserved active centres of both, pro- and eukaryotic proteins with which the non-antibiotics interact and exert antibacterial actions.
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Helliwell KE, Chrachri A, Koester JA, Wharam S, Taylor AR, Wheeler GL, Brownlee C. A Novel Single-Domain Na +-Selective Voltage-Gated Channel in Photosynthetic Eukaryotes. PLANT PHYSIOLOGY 2020; 184:1674-1683. [PMID: 33004614 PMCID: PMC7723092 DOI: 10.1104/pp.20.00889] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
The evolution of Na+-selective four-domain voltage-gated channels (4D-Navs) in animals allowed rapid Na+-dependent electrical excitability, and enabled the development of sophisticated systems for rapid and long-range signaling. While bacteria encode single-domain Na+-selective voltage-gated channels (BacNav), they typically exhibit much slower kinetics than 4D-Navs, and are not thought to have crossed the prokaryote-eukaryote boundary. As such, the capacity for rapid Na+-selective signaling is considered to be confined to certain animal taxa, and absent from photosynthetic eukaryotes. Certainly, in land plants, such as the Venus flytrap (Dionaea muscipula) where fast electrical excitability has been described, this is most likely based on fast anion channels. Here, we report a unique class of eukaryotic Na+-selective, single-domain channels (EukCatBs) that are present primarily in haptophyte algae, including the ecologically important calcifying coccolithophores, Emiliania huxleyi and Scyphosphaera apsteinii The EukCatB channels exhibit very rapid voltage-dependent activation and inactivation kinetics, and isoform-specific sensitivity to the highly selective 4D-Nav blocker tetrodotoxin. The results demonstrate that the capacity for rapid Na+-based signaling in eukaryotes is not restricted to animals or to the presence of 4D-Navs. The EukCatB channels therefore represent an independent evolution of fast Na+-based electrical signaling in eukaryotes that likely contribute to sophisticated cellular control mechanisms operating on very short time scales in unicellular algae.
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Affiliation(s)
- Katherine E Helliwell
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD United Kingdom
| | - Abdul Chrachri
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom
| | - Julie A Koester
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina 28403-591
| | - Susan Wharam
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom
| | - Alison R Taylor
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina 28403-591
| | - Glen L Wheeler
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom
| | - Colin Brownlee
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom
- School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, United Kingdom
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14
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Segura E, Mehta A, Marsolais M, Quan XR, Zhao J, Sauvé R, Spafford JD, Parent L. An ancestral MAGUK protein supports the modulation of mammalian voltage-gated Ca 2+ channels through a conserved Ca Vβ-like interface. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183439. [PMID: 32814116 DOI: 10.1016/j.bbamem.2020.183439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/11/2020] [Accepted: 08/03/2020] [Indexed: 01/09/2023]
Abstract
Eukaryote voltage-gated Ca2+ channels of the CaV2 channel family are hetero-oligomers formed by the pore-forming CaVα1 protein assembled with auxiliary CaVα2δ and CaVβ subunits. CaVβ subunits are formed by a Src homology 3 (SH3) domain and a guanylate kinase (GK) domain connected through a HOOK domain. The GK domain binds a conserved cytoplasmic region of the pore-forming CaVα1 subunit referred as the "AID". Herein we explored the phylogenetic and functional relationship between CaV channel subunits in distant eukaryotic organisms by investigating the function of a MAGUK protein (XM_004990081) cloned from the choanoflagellate Salpingoeca rosetta (Sro). This MAGUK protein (Sroβ) features SH3 and GK structural domains with a 25% primary sequence identity to mammalian CaVβ. Recombinant expression of its cDNA with mammalian high-voltage activated Ca2+ channel CaV2.3 in mammalian HEK cells produced robust voltage-gated inward Ca2+ currents with typical activation and inactivation properties. Like CaVβ, Sroβ prevents fast degradation of total CaV2.3 proteins in cycloheximide assays. The three-dimensional homology model predicts an interaction between the GK domain of Sroβ and the AID motif of the pore-forming CaVα1 protein. Substitution of AID residues Trp (W386A) and Tyr (Y383A) significantly impaired co-immunoprecipitation of CaV2.3 with Sroβ and functional upregulation of CaV2.3 currents. Likewise, a 6-residue deletion within the GK domain of Sroβ, similar to the locus found in mammalian CaVβ, significantly reduced peak current density. Altogether our data demonstrate that an ancestor MAGUK protein reconstitutes the biophysical and molecular features responsible for channel upregulation by mammalian CaVβ through a minimally conserved molecular interface.
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Affiliation(s)
- Emilie Segura
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Canada; Centre de Recherche de l'Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec H1T 1C8, Canada
| | - Amrit Mehta
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Mireille Marsolais
- Centre de Recherche de l'Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec H1T 1C8, Canada
| | - Xin R Quan
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Juan Zhao
- Centre de Recherche de l'Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec H1T 1C8, Canada
| | - Rémy Sauvé
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Canada
| | - J David Spafford
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Lucie Parent
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Canada; Centre de Recherche de l'Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec H1T 1C8, Canada.
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15
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Pozdnyakov I, Safonov P, Skarlato S. Diversity of voltage-gated potassium channels and cyclic nucleotide-binding domain-containing channels in eukaryotes. Sci Rep 2020; 10:17758. [PMID: 33082475 PMCID: PMC7576140 DOI: 10.1038/s41598-020-74971-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 10/06/2020] [Indexed: 12/04/2022] Open
Abstract
Voltage-gated potassium channels (Kv) and cyclic nucleotide-binding domain-containing cation channels HCN, CNG, and KCNH are the evolutionarily related families of ion channels in animals. Their homologues were found in several lineages of eukaryotes and prokaryotes; however, the actual phylogenetic and structural diversity of these ion channels remains unclear. In this work, we present a taxonomically broad investigation of evolutionary relationships and structural diversity of Kv, HCN, CNG, and KCNH and their homologues in eukaryotes focusing on channels from different protistan groups. We demonstrate that both groups of channels consist of a more significant number of lineages than it was shown before, and these lineages can be grouped in two clusters termed Kv-like channels and CNBD-channels. Moreover, we, for the first time, report the unusual two-repeat tandem Kv-like channels and CNBD-channels in several eukaryotic groups, i.e. dinoflagellates, oomycetes, and chlorarachniophytes. Our findings reveal still underappreciated phylogenetic and structural diversity of eukaryotic ion channel lineages.
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Affiliation(s)
- Ilya Pozdnyakov
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, 194064, Russia.
| | - Pavel Safonov
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, 194064, Russia
| | - Sergei Skarlato
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg, 194064, Russia
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Iurova E, Beloborodov E, Tazintseva E, Fomin A, Shutov A, Slesarev S, Saenko Y, Saenko Y. Arthropod toxins inhibiting Ca 2+ and Na + channels prevent AC-1001 H3 peptide-induced apoptosis. J Pept Sci 2020; 27:e3288. [PMID: 33073468 DOI: 10.1002/psc.3288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 08/26/2020] [Accepted: 09/06/2020] [Indexed: 11/06/2022]
Abstract
Peptide toxins of arthropods are one of the potential sources of bioactive substances. Toxins are able to bind to calcium channels and block them. Ca2+ ions play an important role in many cell processes, in particular, in apoptosis. In this work, we study the effect of some arthropod toxins on intracellular processes associated with the induction of apoptosis. Synthetic analogs of U5 -scytotoxin-Sth1a, ω-hexatoxin-Hv1a, ω-theraphotoxin-Hhn2a, and μ-agatoxin-Aa1a toxins-inhibitors of calcium L, P, and Q channels and sodium channels were used in the study. Apoptosis was induced by AC-1001 H3 peptide. We study the effect of toxins on the level of apoptosis, ROS, mitochondrial potential, GSH, and ATP in CHO-K1 cells. We show that all the tested toxins are able to dose dependently block the induction of apoptosis triggered by AC-1001 H3 and reduce the level of natural apoptosis in CHO-K1 cells. Cell incubation with apoptosis inducer AC-1001 H3 in the presence and absence of toxins causes an increase in the intracellular concentrations of ROS, ATP, and mitochondrial potential and decreases the GSH concentration. The present study reveals the antiapoptotic effect of a number of arthropod peptide toxins. The toxins studied can represent a novel approach used in the treatment of pathologies associated with the activation of apoptotic mechanisms.
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Affiliation(s)
- Elena Iurova
- S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Evgenii Beloborodov
- S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Elizaveta Tazintseva
- S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Aleksandr Fomin
- S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Alexander Shutov
- Department of Internal Medicine, Medical Faculty, Ulyanovsk State University, Ulyanovsk, Russia
| | - Sergei Slesarev
- Department of Biology, Ecology and Natural Resources Management, Faculty of Ecology, Ulyanovsk State University, Ulyanovsk, Russia
| | - Yana Saenko
- S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
| | - Yury Saenko
- S. P. Kapitsa Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
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17
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Romanova DY, Smirnov IV, Nikitin MA, Kohn AB, Borman AI, Malyshev AY, Balaban PM, Moroz LL. Sodium action potentials in placozoa: Insights into behavioral integration and evolution of nerveless animals. Biochem Biophys Res Commun 2020; 532:120-126. [PMID: 32828537 DOI: 10.1016/j.bbrc.2020.08.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 08/09/2020] [Indexed: 01/20/2023]
Abstract
Placozoa are small disc-shaped animals, representing the simplest known, possibly ancestral, organization of free-living animals. With only six morphological distinct cell types, without any recognized neurons or muscle, placozoans exhibit fast effector reactions and complex behaviors. However, little is known about electrogenic mechanisms in these animals. Here, we showed the presence of rapid action potentials in four species of placozoans (Trichoplax adhaerens [H1 haplotype], Trichoplax sp.[H2], Hoilungia hongkongensis [H13], and Hoilungia sp. [H4]). These action potentials are sodium-dependent and can be inducible. The molecular analysis suggests the presence of 5-7 different types of voltage-gated sodium channels, which showed substantial evolutionary radiation compared to many other metazoans. Such unexpected diversity of sodium channels in early-branched metazoan lineages reflect both duplication events and parallel evolution of unique behavioral integration in these nerveless animals.
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Affiliation(s)
- Daria Y Romanova
- Institute of Higher Nervous Activity and Neurophysiology, Moscow, 117485, Russia.
| | - Ivan V Smirnov
- Institute of Higher Nervous Activity and Neurophysiology, Moscow, 117485, Russia
| | - Mikhail A Nikitin
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119991, Russia
| | - Andrea B Kohn
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, 32080, USA
| | - Alisa I Borman
- Department of Evolutionary Biology, Biological Faculty, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Alexey Y Malyshev
- Institute of Higher Nervous Activity and Neurophysiology, Moscow, 117485, Russia
| | - Pavel M Balaban
- Institute of Higher Nervous Activity and Neurophysiology, Moscow, 117485, Russia.
| | - Leonid L Moroz
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, 32080, USA; Department of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
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Guidelli R, Becucci L. Deterministic model of Ca v3.1 Ca 2+ channel and a proposed sequence of its conformations. Bioelectrochemistry 2020; 136:107618. [PMID: 32795940 DOI: 10.1016/j.bioelechem.2020.107618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 06/29/2020] [Accepted: 07/21/2020] [Indexed: 10/23/2022]
Abstract
A family of current-time curves of T-type Cav3.1 Ca2+ channels available in the literature is simulated by a kinetic model differing from that used for the interpretation of all salient features of Na+ and Shaker K+ channels by the insertion of a multiplying factor expressing the difference between the working potential ϕ and the reversal potential ϕr. This deterministic model is also used to simulate experimental curves taken from the literature for steady-state 'fast inactivation' and for a gradual passage from fast to 'slow inactivation'. A depolarizing pulse induces fast or slow inactivation depending on whether it lasts 100-500 ms or about 1 min, and is believed to cause a collapse of the central pore near the selectivity filter (SF). A number of features of fast and slow inactivation of Cav3.1 Ca2+ channels are qualitatively interpreted on the basis of a sequence of conformational states. Briefly, the conformation responsible for 'fast inactivation' is assumed to have the activation gate open and the inactivation gate (i.e., the SF) inactive. Immediately after a depolarizing pulse, this conformation is inactive and requires a sufficiently long rest time at a far negative holding potential to recover from inactivation. 'Slow inactivation' is ascribed to a different conformation with the activation gate closed and the SF inactive.
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Affiliation(s)
- Rolando Guidelli
- Department of Chemistry "Ugo Schiff", Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy.
| | - Lucia Becucci
- Department of Chemistry "Ugo Schiff", Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy
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19
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Mackrill JJ, Shiels HA. Evolution of Excitation-Contraction Coupling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:281-320. [DOI: 10.1007/978-3-030-12457-1_12] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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20
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Chaos theory discloses triggers and drivers of plankton dynamics in stable environment. Sci Rep 2019; 9:20351. [PMID: 31889119 PMCID: PMC6937249 DOI: 10.1038/s41598-019-56851-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 12/16/2019] [Indexed: 11/08/2022] Open
Abstract
Despite the enticing discoveries of chaos in nature, triggers and drivers of this phenomenon remain a classical enigma which needs irrefutable empirical evidence. Here we analyze results of the yearlong replicated mesocosm experiment with multi-species plankton community that allowed revealing signs of chaos at different trophic levels in strictly controlled abiotic environment. In mesocosms without external stressors, we observed the “paradox of chaos” when biotic interactions (internal drivers) were acting as generators of internal abiotic triggers of complex plankton dynamics. Chaos was registered as episodes that vanished unpredictably or were substituted by complex behaviour of other candidates when longer time series were considered. Remarkably, episodes of chaos were detected even in the most abiotically stable conditions. We developed the Integral Chaos Indicator to validate the results of the Lyapunov exponent analysis. These findings are essential for modelling and forecasting behaviour of a variety of natural and other global systems.
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Alternative Mechanisms for Fast Na +/Ca 2+ Signaling in Eukaryotes via a Novel Class of Single-Domain Voltage-Gated Channels. Curr Biol 2019; 29:1503-1511.e6. [PMID: 31006567 PMCID: PMC6509283 DOI: 10.1016/j.cub.2019.03.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/11/2019] [Accepted: 03/20/2019] [Indexed: 01/16/2023]
Abstract
Rapid Na+/Ca2+-based action potentials govern essential cellular functions in eukaryotes, from the motile responses of unicellular protists, such as Paramecium [1, 2], to complex animal neuromuscular activity [3]. A key innovation underpinning this fundamental signaling process has been the evolution of four-domain voltage-gated Na+/Ca2+ channels (4D-Cavs/Navs). These channels are widely distributed across eukaryote diversity [4], albeit several eukaryotes, including land plants and fungi, have lost voltage-sensitive 4D-Cav/Navs [5, 6, 7]. Because these lineages appear to lack rapid Na+/Ca2+-based action potentials, 4D-Cav/Navs are generally considered necessary for fast Na+/Ca2+-based signaling [7]. However, the cellular mechanisms underpinning the membrane physiology of many eukaryotes remain unexamined. Eukaryotic phytoplankton critically influence our climate as major primary producers. Several taxa, including the globally abundant diatoms, exhibit membrane excitability [8, 9, 10]. We previously demonstrated that certain diatom genomes encode 4D-Cav/Navs [4] but also proteins of unknown function, resembling prokaryote single-domain, voltage-gated Na+ channels (BacNavs) [4]. Here, we show that single-domain channels are actually broadly distributed across major eukaryote phytoplankton lineages and represent three novel classes of single-domain channels, which we refer collectively to as EukCats. Functional characterization of diatom EukCatAs indicates that they are voltage-gated Na+- and Ca2+-permeable channels, with rapid kinetics resembling metazoan 4D-Cavs/Navs. In Phaeodactylum tricornutum, which lacks 4D-Cav/Navs, EukCatAs underpin voltage-activated Ca2+ signaling important for membrane excitability, and mutants exhibit impaired motility. EukCatAs therefore provide alternative mechanisms for rapid Na+/Ca2+ signaling in eukaryotes and may functionally replace 4D-Cavs/Navs in pennate diatoms. Marine phytoplankton thus possess unique signaling mechanisms that may be key to environmental sensing in the oceans. Novel class of single-domain, voltage-gated channels (EukCatAs) identified in diatoms EukCatAs are fast voltage-gated Na+- and Ca2+-permeable channels EukCatAs underpin voltage-activated Ca2+ signaling and membrane excitability EukCatAs may have functionally replaced 4D-Cav/Nav channels in pennate diatoms
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