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Maatoug S, Cheikh A, Khamessi O, Tabka H, Landoulsi Z, Guigonis JM, Diochot S, Bendahhou S, Benkhalifa R. Cross Pharmacological, Biochemical and Computational Studies of a Human Kv3.1b Inhibitor from Androctonus australis Venom. Int J Mol Sci 2021; 22:ijms222212290. [PMID: 34830172 PMCID: PMC8618407 DOI: 10.3390/ijms222212290] [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] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/05/2021] [Accepted: 11/11/2021] [Indexed: 11/23/2022] Open
Abstract
The voltage-gated K+ channels Kv3.1 display fast activation and deactivation kinetics and are known to have a crucial contribution to the fast-spiking phenotype of certain neurons. AahG50, as a natural product extracted from Androctonus australis hector venom, inhibits selectively Kv3.1 channels. In the present study, we focused on the biochemical and pharmacological characterization of the component in AahG50 scorpion venom that potently and selectively blocks the Kv3.1 channels. We used a combined optimization through advanced biochemical purification and patch-clamp screening steps to characterize the peptide in AahG50 active on Kv3.1 channels. We described the inhibitory effect of a toxin on Kv3.1 unitary current in black lipid bilayers. In silico, docking experiments are used to study the molecular details of the binding. We identified the first scorpion venom peptide inhibiting Kv3.1 current at 170 nM. This toxin is the alpha-KTx 15.1, which occludes the Kv3.1 channel pore by means of the lysine 27 lateral chain. This study highlights, for the first time, the modulation of the Kv3.1 by alpha-KTx 15.1, which could be an interesting starting compound for developing therapeutic biomolecules against Kv3.1-associated diseases.
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Affiliation(s)
- Sonia Maatoug
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Correspondence: (S.M.); (R.B.); Tel.: +216-98-81-27-32 (R.B.)
| | - Amani Cheikh
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
| | - Oussema Khamessi
- Laboratoire des Biomolécules Thérapeutiques, Institut Pasteur de Tunis, Université de Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia;
| | - Hager Tabka
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Faculté des Sciences de Bizerte, Université de Carthage, Bizerte 7021, Tunisia
| | - Zied Landoulsi
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
| | - Jean-Marie Guigonis
- Laboratory Transporter in Imaging and Radiotherapy in Oncology (TIRO), Direction de la Recherche Fondamentale (DRF), Institut des Sciences du Vivant Fréderic Joliot, Commissariat à l′Energie Atomique et aux Énergies Alternatives (CEA), Université Côte d’Azur, F-06107 Nice, France;
| | - Sylvie Diochot
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France;
| | - Saïd Bendahhou
- UMR7370 CNRS, LP2M, Université Côte d’Azur, Labex ICST, Nice, France;
| | - Rym Benkhalifa
- Laboratoire Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université Tunis El Manar, 13 Place Pasteur BP74, Tunis 1002, Tunisia; (A.C.); (H.T.); (Z.L.)
- Correspondence: (S.M.); (R.B.); Tel.: +216-98-81-27-32 (R.B.)
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Dobson JS, Harris RJ, Zdenek CN, Huynh T, Hodgson WC, Bosmans F, Fourmy R, Violette A, Fry BG. The Dragon's Paralysing Spell: Evidence of Sodium and Calcium Ion Channel Binding Neurotoxins in Helodermatid and Varanid Lizard Venoms. Toxins (Basel) 2021; 13:toxins13080549. [PMID: 34437420 PMCID: PMC8402328 DOI: 10.3390/toxins13080549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 12/19/2022] Open
Abstract
Bites from helodermatid lizards can cause pain, paresthesia, paralysis, and tachycardia, as well as other symptoms consistent with neurotoxicity. Furthermore, in vitro studies have shown that Heloderma horridum venom inhibits ion flux and blocks the electrical stimulation of skeletal muscles. Helodermatids have long been considered the only venomous lizards, but a large body of robust evidence has demonstrated venom to be a basal trait of Anguimorpha. This clade includes varanid lizards, whose bites have been reported to cause anticoagulation, pain, and occasionally paralysis and tachycardia. Despite the evolutionary novelty of these lizard venoms, their neuromuscular targets have yet to be identified, even for the iconic helodermatid lizards. Therefore, to fill this knowledge gap, the venoms of three Heloderma species (H. exasperatum, H. horridum and H. suspectum) and two Varanus species (V. salvadorii and V. varius) were investigated using Gallus gallus chick biventer cervicis nerve–muscle preparations and biolayer interferometry assays for binding to mammalian ion channels. Incubation with Heloderma venoms caused the reduction in nerve-mediated muscle twitches post initial response of avian skeletal muscle tissue preparation assays suggesting voltage-gated sodium (NaV) channel binding. Congruent with the flaccid paralysis inducing blockage of electrical stimulation in the skeletal muscle preparations, the biolayer interferometry tests with Heloderma suspectum venom revealed binding to the S3–S4 loop within voltage-sensing domain IV of the skeletal muscle channel subtype, NaV1.4. Consistent with tachycardia reported in clinical cases, the venom also bound to voltage-sensing domain IV of the cardiac smooth muscle calcium channel, CaV1.2. While Varanus varius venom did not have discernable effects in the avian tissue preparation assay at the concentration tested, in the biointerferometry assay both V. varius and V. salvadorii bound to voltage-sensing domain IV of both NaV1.4 and CaV1.2, similar to H. suspectum venom. The ability of varanid venoms to bind to mammalian ion channels but not to the avian tissue preparation suggests prey-selective actions, as did the differential potency within the Heloderma venoms for avian versus mammalian pathophysiological targets. This study thus presents the detailed characterization of Heloderma venom ion channel neurotoxicity and offers the first evidence of varanid lizard venom neurotoxicity. In addition, the data not only provide information useful to understanding the clinical effects produced by envenomations, but also reveal their utility as physiological probes, and underscore the potential utility of neglected venomous lineages in the drug design and development pipeline.
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Affiliation(s)
- James S. Dobson
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.S.D.); (R.J.H.); (C.N.Z.)
| | - Richard J. Harris
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.S.D.); (R.J.H.); (C.N.Z.)
| | - Christina N. Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.S.D.); (R.J.H.); (C.N.Z.)
| | - Tam Huynh
- Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; (T.H.); (W.C.H.)
| | - Wayne C. Hodgson
- Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; (T.H.); (W.C.H.)
| | - Frank Bosmans
- Department of Basic and Applied Medical Sciences, Ghent University, 9000 Ghent, Belgium;
| | - Rudy Fourmy
- Alphabiotoxine Laboratory sprl, Barberie 15, 7911 Montroeul-au-Bois, Belgium; (R.F.); (A.V.)
| | - Aude Violette
- Alphabiotoxine Laboratory sprl, Barberie 15, 7911 Montroeul-au-Bois, Belgium; (R.F.); (A.V.)
| | - Bryan G. Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.S.D.); (R.J.H.); (C.N.Z.)
- Correspondence: ; Tel.: +61-7-336-58515
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Martin-Eauclaire MF, Bougis PE, de Lima ME. Ts1 from the Brazilian scorpion Tityus serrulatus: A half-century of studies on a multifunctional beta like-toxin. Toxicon 2018; 152:106-120. [PMID: 30059695 DOI: 10.1016/j.toxicon.2018.07.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/18/2018] [Accepted: 07/24/2018] [Indexed: 12/19/2022]
Abstract
The Tityus serrulatus scorpion species represents a serious human health threat to in Brazil because it is among the animals that produces the most dangerous venoms for mammals in South America. Its venom has provided several highly selective ligands that specifically interact with sodium and potassium channels. During the past decades, several international groups published an increasing amount of data on the isolation and the chemical, pharmacological and immunological characterisation of its main β-toxin, Ts1. In this review, we compiled the best available past and recent knowledge on Ts1. Aside from its intricate purification, the state-of-the-art understanding concerning its pharmacological activities is presented. Its solved three-dimensional structure is shown, as well as the possible surface areas of contact between Ts1 and its diverse voltage-gated Na+ channel targets. Organisations of the gene and the precursor encoding Ts1 are also tackled based on available cDNA clones or on information obtained from polymerase chain reactions of stretches of scorpion DNA. At last, the immunological studies complete with Ts1 to set up an efficient immunotherapy against the Tityus serrulatus venom are summarized.
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Affiliation(s)
| | - Pierre E Bougis
- Aix Marseille Univ, CNRS, LNC, UMR 7291, 13003, Marseille, France.
| | - Maria Elena de Lima
- Laboratório de Venenos e Toxinas Animais, Depto de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil; Instituto de Ensino e Pesquisa da Santa Casa de Belo Horizonte - IEP/SCBH, 30150-240, Belo Horizonte, MG, Brazil.
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Wang L, Zellmer SG, Printzenhoff DM, Castle NA. PF-06526290 can both enhance and inhibit conduction through voltage-gated sodium channels. Br J Pharmacol 2018; 175:2926-2939. [PMID: 29791744 DOI: 10.1111/bph.14338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 03/06/2018] [Accepted: 03/17/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND AND PURPOSE Pharmacological agents that either inhibit or enhance flux of ions through voltage-gated sodium (Nav ) channels may provide opportunities for treatment of human health disorders. During studies to characterize agents that modulate Nav 1.3 function, we identified a compound that appears to exhibit both enhancement and inhibition of sodium ion conduction that appeared to be dependent on the gating state that the channel was in. The objective of the current study was to determine if these different modulatory effects are mediated by the same or distinct interactions with the channel. EXPERIMENTAL APPROACH Electrophysiology and site-directed mutation were used to investigate the effects of PF-06526290 on Nav channel function. KEY RESULTS PF-06526290 greatly slows inactivation of Nav channels in a subtype-independent manner. However, upon prolonged depolarization to induce inactivation, PF-06526290 becomes a Nav subtype-selective inhibitor. Mutation of the domain 4 voltage sensor modulates inhibition of Nav 1.3 or Nav 1.7 channels by PF-06526290 but has no effect on PF-06526290 mediated slowing of inactivation. CONCLUSIONS AND IMPLICATIONS These findings suggest that distinct interactions may underlie the two modes of Nav channel modulation by PF-06526290 and that a single compound can affect sodium channel function in several ways.
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Affiliation(s)
- Lingxin Wang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
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Gilchrist J, Bosmans F. Using voltage-sensor toxins and their molecular targets to investigate Na V 1.8 gating. J Physiol 2018; 596:1863-1872. [PMID: 29193176 DOI: 10.1113/jp275102] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/16/2017] [Indexed: 01/10/2023] Open
Abstract
Voltage-gated sodium (NaV ) channel gating is a complex phenomenon which involves a distinct contribution of four integral voltage-sensing domains (VSDI, VSDII, VSDIII and VSDIV). Utilizing accrued pharmacological and structural insights, we build on an established chimera approach to introduce animal toxin sensitivity in each VSD of an acceptor channel by transferring in portable S3b-S4 motifs from the four VSDs of a toxin-susceptible donor channel (NaV 1.2). By doing so, we observe that in NaV 1.8, a relatively unexplored channel subtype with distinctly slow gating kinetics, VSDI-III participate in channel opening whereas VSDIV can regulate opening as well as fast inactivation. These results illustrate the effectiveness of a pharmacological approach to investigate the mechanism underlying gating of a mammalian NaV channel complex.
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Affiliation(s)
- John Gilchrist
- Department of Physiology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Frank Bosmans
- Department of Physiology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
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Kuldyushev NA, Berkut AA, Peigneur S, Tytgat J, Grishin EV, Vassilevski AA. Design of sodium channel ligands with defined selectivity - a case study in scorpion alpha-toxins. FEBS Lett 2017; 591:3414-3420. [DOI: 10.1002/1873-3468.12839] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 08/31/2017] [Accepted: 08/31/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Nikita A. Kuldyushev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; Russian Academy of Sciences; Moscow Russia
- Moscow Institute of Physics and Technology (State University); Russia
| | - Antonina A. Berkut
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; Russian Academy of Sciences; Moscow Russia
- Moscow Institute of Physics and Technology (State University); Russia
| | - Steve Peigneur
- Toxicology and Pharmacology; University of Leuven; Belgium
| | - Jan Tytgat
- Toxicology and Pharmacology; University of Leuven; Belgium
| | - Eugene V. Grishin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; Russian Academy of Sciences; Moscow Russia
| | - Alexander A. Vassilevski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry; Russian Academy of Sciences; Moscow Russia
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Rajamani R, Wu S, Rodrigo I, Gao M, Low S, Megson L, Wensel D, Pieschl RL, Post-Munson DJ, Watson J, Langley DR, Ahlijanian MK, Bristow LJ, Herrington J. A Functional NaV1.7-NaVAb Chimera with a Reconstituted High-Affinity ProTx-II Binding Site. Mol Pharmacol 2017. [DOI: 10.1124/mol.117.108712] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Ahern CA, Payandeh J, Bosmans F, Chanda B. The hitchhiker's guide to the voltage-gated sodium channel galaxy. ACTA ACUST UNITED AC 2016; 147:1-24. [PMID: 26712848 PMCID: PMC4692491 DOI: 10.1085/jgp.201511492] [Citation(s) in RCA: 230] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Eukaryotic voltage-gated sodium (Nav) channels contribute to the rising phase of action potentials and served as an early muse for biophysicists laying the foundation for our current understanding of electrical signaling. Given their central role in electrical excitability, it is not surprising that (a) inherited mutations in genes encoding for Nav channels and their accessory subunits have been linked to excitability disorders in brain, muscle, and heart; and (b) Nav channels are targeted by various drugs and naturally occurring toxins. Although the overall architecture and behavior of these channels are likely to be similar to the more well-studied voltage-gated potassium channels, eukaryotic Nav channels lack structural and functional symmetry, a notable difference that has implications for gating and selectivity. Activation of voltage-sensing modules of the first three domains in Nav channels is sufficient to open the channel pore, whereas movement of the domain IV voltage sensor is correlated with inactivation. Also, structure–function studies of eukaryotic Nav channels show that a set of amino acids in the selectivity filter, referred to as DEKA locus, is essential for Na+ selectivity. Structures of prokaryotic Nav channels have also shed new light on mechanisms of drug block. These structures exhibit lateral fenestrations that are large enough to allow drugs or lipophilic molecules to gain access into the inner vestibule, suggesting that this might be the passage for drug entry into a closed channel. In this Review, we will synthesize our current understanding of Nav channel gating mechanisms, ion selectivity and permeation, and modulation by therapeutics and toxins in light of the new structures of the prokaryotic Nav channels that, for the time being, serve as structural models of their eukaryotic counterparts.
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Affiliation(s)
- Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242
| | - Jian Payandeh
- Department of Structural Biology, Genentech, Inc., South San Francisco, CA 94080
| | - Frank Bosmans
- Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205 Department of Physiology and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
| | - Baron Chanda
- Department of Neuroscience and Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705 Department of Neuroscience and Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705
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Martin-Eauclaire MF, Salvatierra J, Bosmans F, Bougis PE. The scorpion toxin Bot IX is a potent member of the α-like family and has a unique N-terminal sequence extension. FEBS Lett 2016; 590:3221-32. [DOI: 10.1002/1873-3468.12357] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 08/05/2016] [Accepted: 08/05/2016] [Indexed: 11/08/2022]
Affiliation(s)
| | - Juan Salvatierra
- Department of Physiology; School of Medicine; Johns Hopkins University; Baltimore MD USA
| | - Frank Bosmans
- Department of Physiology; School of Medicine; Johns Hopkins University; Baltimore MD USA
- Solomon H. Snyder Department of Neuroscience; School of Medicine; Johns Hopkins University; Baltimore MD USA
| | - Pierre E. Bougis
- Aix Marseille Université; CNRS; CRN2M; UMR7286; PFRN-CAPM; Marseille France
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Wang L, Zellmer SG, Printzenhoff DM, Castle NA. Addition of a single methyl group to a small molecule sodium channel inhibitor introduces a new mode of gating modulation. Br J Pharmacol 2015. [PMID: 26220736 DOI: 10.1111/bph.13259] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Aryl sulfonamide Nav 1.3 or Nav 1.7 voltage-gated sodium (Nav ) channel inhibitors interact with the Domain 4 voltage sensor domain (D4 VSD). During studies to better understand the structure-activity relationship of this interaction, an additional mode of channel modulation, specifically slowing of inactivation, was revealed by addition of a single methyl moiety. The objective of the current study was to determine if these different modulatory effects are mediated by the same or distinct interactions with the channel. EXPERIMENTAL APPROACH Electrophysiology and site-directed mutation were used to compare the effects of PF-06526290 and its desmethyl analogue PF-05661014 on Nav channel function. KEY RESULTS PF-05661014 selectively inhibits Nav 1.3 versus Nav 1.7 currents by stabilizing inactivated channels via interaction with D4 VSD. In contrast, PF-06526290, which differs from PF-05661014 by a single methyl group, exhibits a dual effect. It greatly slows inactivation of Nav channels in a subtype-independent manner. However, upon prolonged depolarization to induce inactivation, PF-06526290 becomes a Nav subtype selective inhibitor similar to PF-05661014. Mutation of the D4 VSD modulates inhibition of Nav 1.3 or Nav 1.7 by both PF-05661014 and PF-06526290, but has no effect on the inactivation slowing produced by PF-06526290. This finding, along with the absence of functional inhibition of PF-06526290-induced inactivation slowing by PF-05661014, suggests that distinct interactions underlie the two modes of Nav channel modulation. CONCLUSIONS AND IMPLICATIONS Addition of a methyl group to a Nav channel inhibitor introduces an additional mode of gating modulation, implying that a single compound can affect sodium channel function in multiple ways.
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Abstract
It is long known that peptide neurotoxins derived from a diversity of venomous animals evolve by positive selection following gene duplication, yet a force that drives their adaptive evolution remains a mystery. By using maximum-likelihood models of codon substitution, we analyzed molecular adaptation in scorpion sodium channel toxins from a specific species and found ten positively selected sites, six of which are located at the core-domain of scorpion α-toxins, a region known to interact with two adjacent loops in the voltage-sensor domain (DIV) of sodium channels, as validated by our newly constructed computational model of toxin-channel complex. Despite the lack of positive selection signals in these two loops, they accumulated extensive sequence variations by relaxed purifying selection in prey and predators of scorpions. The evolutionary variability in the toxin-bound regions of sodium channels indicates that accelerated substitutions in the multigene family of scorpion toxins is a consequence of dealing with the target diversity. This work presents an example of atypical co-evolution between animal toxins and their molecular targets, in which toxins suffered from more prominent selective pressure from the channels of their competitors. Our discovery helps explain the evolutionary rationality of gene duplication of toxins in a specific venomous species.
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Camargos TS, Bosmans F, Rego SC, Mourão CBF, Schwartz EF. The Scorpion Toxin Tf2 from Tityus fasciolatus Promotes Nav1.3 Opening. PLoS One 2015; 10:e0128578. [PMID: 26083731 PMCID: PMC4470819 DOI: 10.1371/journal.pone.0128578] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 04/29/2015] [Indexed: 11/23/2022] Open
Abstract
We identified Tf2, the first β-scorpion toxin from the venom of the Brazilian scorpion Tityus fasciolatus. Tf2 is identical to Tb2-II found in Tityus bahiensis. We found that Tf2 selectively activates human (h)Nav1.3, a neuronal voltage-gated sodium (Nav) subtype implicated in epilepsy and nociception. Tf2 shifts hNav1.3 activation voltage to more negative values, thereby opening the channel at resting membrane potentials. Seven other tested mammalian Nav channels (Nav1.1-1.2; Nav1.4-1.8) expressed in Xenopus oocytes are insensitive upon application of 1 μM Tf2. Therefore, the identification of Tf2 represents a unique addition to the repertoire of animal toxins that can be used to investigate Nav channel function.
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Affiliation(s)
- Thalita S. Camargos
- Departamento de Ciências Fisiológicas, Laboratório de Toxinologia, Universidade de Brasília, Brasília, DF, Brazil
| | - Frank Bosmans
- Department of Physiology, Johns Hopkins University—School of Medicine, Baltimore, MD, United States of America
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University—School of Medicine, Baltimore, MD, United States of America
| | - Solange C. Rego
- Departamento de Ciências Fisiológicas, Laboratório de Toxinologia, Universidade de Brasília, Brasília, DF, Brazil
| | - Caroline B. F. Mourão
- Departamento de Ciências Fisiológicas, Laboratório de Toxinologia, Universidade de Brasília, Brasília, DF, Brazil
| | - Elisabeth F. Schwartz
- Departamento de Ciências Fisiológicas, Laboratório de Toxinologia, Universidade de Brasília, Brasília, DF, Brazil
- * E-mail:
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Adler EM. Of transporter design, screening for gating modifiers, and how TRAAK gates. J Gen Physiol 2015; 145:91-2. [PMID: 25624447 PMCID: PMC4306710 DOI: 10.1085/jgp.201411351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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