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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.
James Dobson; Richard Harris; Christina Zdenek; Tam Huynh; Wayne Hodgson; Frank Bosmans; Rudy Fourmy; Aude Violette; Bryan Fry. The Dragon’s Paralysing Spell: Evidence of Sodium and Calcium Ion Channel Binding Neurotoxins in Helodermatid and Varanid Lizard Venoms. Toxins 2021, 13, 549 .
AMA StyleJames Dobson, Richard Harris, Christina Zdenek, Tam Huynh, Wayne Hodgson, Frank Bosmans, Rudy Fourmy, Aude Violette, Bryan Fry. The Dragon’s Paralysing Spell: Evidence of Sodium and Calcium Ion Channel Binding Neurotoxins in Helodermatid and Varanid Lizard Venoms. Toxins. 2021; 13 (8):549.
Chicago/Turabian StyleJames Dobson; Richard Harris; Christina Zdenek; Tam Huynh; Wayne Hodgson; Frank Bosmans; Rudy Fourmy; Aude Violette; Bryan Fry. 2021. "The Dragon’s Paralysing Spell: Evidence of Sodium and Calcium Ion Channel Binding Neurotoxins in Helodermatid and Varanid Lizard Venoms." Toxins 13, no. 8: 549.
We identified nine patients from four unrelated families harboring three biallelic variants in SCN1B (NM_001037.5: c.136C>T; p.[Arg46Cys], c.178C>T; p.[Arg60Cys], and c.472G>A; p.[Val158Met]). All subjects presented with early infantile epileptic encephalopathy 52 (EIEE52), a rare, severe developmental and epileptic encephalopathy featuring infantile onset refractory seizures followed by developmental stagnation or regression. Because SCN1B influences neuronal excitability through modulation of voltage‐gated sodium (NaV) channel function, we examined the effects of human SCN1BR46C (β1R46C), SCN1BR60C (β1R60C), and SCN1BV158M (β1V158M) on the three predominant brain NaV channel subtypes NaV1.1 (SCN1A), NaV1.2 (SCN2A), and NaV1.6 (SCN8A). We observed a shift toward more depolarizing potentials of conductance–voltage relationships (NaV1.2/β1R46C, NaV1.2/β1R60C, NaV1.6/β1R46C, NaV1.6/β1R60C, and NaV1.6/β1V158M) and channel availability (NaV1.1/β1R46C, NaV1.1/β1V158M, NaV1.2/β1R46C, NaV1.2/β1R60C, and NaV1.6/β1V158M), and detected a slower recovery from fast inactivation for NaV1.1/β1V158M. Combined with modeling data indicating perturbation‐induced structural changes in β1, these results suggest that the SCN1B variants reported here can disrupt normal NaV channel function in the brain, which may contribute to EIEE52.
Marcello Scala; Stephanie Efthymiou; Tipu Sultan; Jolien De Waele; Marta Panciroli; Vincenzo Salpietro; Reza Maroofian; Pasquale Striano; Filip Van Petegem; Henry Houlden; Frank Bosmans. Homozygous SCN1B variants causing early infantile epileptic encephalopathy 52 affect voltage‐gated sodium channel function. Epilepsia 2021, 62, 1 .
AMA StyleMarcello Scala, Stephanie Efthymiou, Tipu Sultan, Jolien De Waele, Marta Panciroli, Vincenzo Salpietro, Reza Maroofian, Pasquale Striano, Filip Van Petegem, Henry Houlden, Frank Bosmans. Homozygous SCN1B variants causing early infantile epileptic encephalopathy 52 affect voltage‐gated sodium channel function. Epilepsia. 2021; 62 (6):1.
Chicago/Turabian StyleMarcello Scala; Stephanie Efthymiou; Tipu Sultan; Jolien De Waele; Marta Panciroli; Vincenzo Salpietro; Reza Maroofian; Pasquale Striano; Filip Van Petegem; Henry Houlden; Frank Bosmans. 2021. "Homozygous SCN1B variants causing early infantile epileptic encephalopathy 52 affect voltage‐gated sodium channel function." Epilepsia 62, no. 6: 1.
Background: Voltage-gated sodium (NaV) channels help regulate electrical activity of the plasma membrane. Mutations in associated subunits can result in pathological outcomes. Here we examined the interaction of NaV channels with cardiac arrhythmia-linked mutations in SCN2B and SCN4B, two genes that encode auxiliary β-subunits.Materials and Methods: To investigate changes in SCN2BR137H and SCN4BI80T function, we combined three-dimensional X-ray crystallography with electrophysiological measurements on NaV1.5, the dominant subtype in the heart.Results:SCN4BI80T alters channel activity, whereas SCN2BR137H does not have an apparent effect. Structurally, the SCN4BI80T perturbation alters hydrophobic packing of the subunit with major structural changes and causes a thermal destabilization of the folding. In contrast, SCN2BR137H leads to structural changes but overall protein stability is unaffected.Conclusion:SCN4BI80T data suggest a functionally important region in the interaction between NaV1.5 and β4 that, when disrupted, could lead to channel dysfunction. A lack of apparent functional effects of SCN2BR137H on NaV1.5 suggests an alternative working mechanism, possibly through other NaV channel subtypes present in heart tissue. Indeed, mapping the structural variations of SCN2BR137H onto neuronal NaV channel structures suggests altered interaction patterns.
José P. Llongueras; Samir Das; Jolien De Waele; Lucio Capulzini; Antonio Sorgente; Filip Van Petegem; Frank Bosmans. Biophysical Investigation of Sodium Channel Interaction with β-Subunit Variants Associated with Arrhythmias. Bioelectricity 2020, 2, 269 -278.
AMA StyleJosé P. Llongueras, Samir Das, Jolien De Waele, Lucio Capulzini, Antonio Sorgente, Filip Van Petegem, Frank Bosmans. Biophysical Investigation of Sodium Channel Interaction with β-Subunit Variants Associated with Arrhythmias. Bioelectricity. 2020; 2 (3):269-278.
Chicago/Turabian StyleJosé P. Llongueras; Samir Das; Jolien De Waele; Lucio Capulzini; Antonio Sorgente; Filip Van Petegem; Frank Bosmans. 2020. "Biophysical Investigation of Sodium Channel Interaction with β-Subunit Variants Associated with Arrhythmias." Bioelectricity 2, no. 3: 269-278.
Management of chronic pain presents a major challenge, since many currently available treatments lack efficacy and have problems such as addiction and tolerance. Loss of function mutations in the SCN9A gene lead to a congenital inability to feel pain, with no other sensory deficits aside from anosmia. SCN9A encodes the voltage-gated sodium (NaV) channel 1.7 (NaV1.7), which has been identified as a primary pain target. However, in developing NaV1.7-targeted analgesics, extreme care must to be taken to avoid off-target activity on other NaV subtypes that are critical for survival. Since spider venoms are an excellent source of NaV channel modulators, we screened a panel of spider venoms to identify selective NaV1.7 inhibitors. This led to identification of two novel NaV modulating venom peptides (β/μ-theraphotoxin-Pe1a and β/μ-theraphotoxin-Pe1b (Pe1b) from the arboreal tarantula Phormingochilus everetti. A third peptide isolated from the tarantula Bumba pulcherrimaklaasi was identical to the well-known ProTx-I (β/ω-theraphotoxin-Tp1a) from the tarantula Thrixopelma pruriens. A tethered toxin (t-toxin)-based alanine scanning strategy was used to determine the NaV1.7 pharmacophore of ProTx-I. We designed several ProTx-I and Pe1b analogues, and tested them for activity and NaV channel subtype selectivity. Several analogues had improved potency against NaV1.7, and altered specificity against other NaV channels. These analogues provide a foundation for development of Pe1b as a lead molecule for therapeutic inhibition of NaV1.7.
Darshani B. Rupasinghe; Volker Herzig; Irina Vetter; Zoltan Dekan; John Gilchrist; Frank Bosmans; Paul F. Alewood; Richard J. Lewis; Glenn F. King. Mutational analysis of ProTx-I and the novel venom peptide Pe1b provide insight into residues responsible for selective inhibition of the analgesic drug target NaV1.7. Biochemical Pharmacology 2020, 181, 114080 .
AMA StyleDarshani B. Rupasinghe, Volker Herzig, Irina Vetter, Zoltan Dekan, John Gilchrist, Frank Bosmans, Paul F. Alewood, Richard J. Lewis, Glenn F. King. Mutational analysis of ProTx-I and the novel venom peptide Pe1b provide insight into residues responsible for selective inhibition of the analgesic drug target NaV1.7. Biochemical Pharmacology. 2020; 181 ():114080.
Chicago/Turabian StyleDarshani B. Rupasinghe; Volker Herzig; Irina Vetter; Zoltan Dekan; John Gilchrist; Frank Bosmans; Paul F. Alewood; Richard J. Lewis; Glenn F. King. 2020. "Mutational analysis of ProTx-I and the novel venom peptide Pe1b provide insight into residues responsible for selective inhibition of the analgesic drug target NaV1.7." Biochemical Pharmacology 181, no. : 114080.
Phlotoxin-1 (PhlTx1) is a peptide previously identified in tarantula venom (Phlogius species) that belongs to the inhibitory cysteine-knot (ICK) toxin family. Like many ICK-based spider toxins, the synthesis of PhlTx1 appears particularly challenging, mostly for obtaining appropriate folding and concomitant suitable disulfide bridge formation. Herein, we describe a procedure for the chemical synthesis and the directed sequential disulfide bridge formation of PhlTx1 that allows for a straightforward production of this challenging peptide. We also performed extensive functional testing of PhlTx1 on 31 ion channel types and identified the voltage-gated sodium (Nav) channel Nav1.7 as the main target of this toxin. Moreover, we compared PhlTx1 activity to 10 other spider toxin activities on an automated patch-clamp system with Chinese Hamster Ovary (CHO) cells expressing human Nav1.7. Performing these analyses in reproducible conditions allowed for classification according to the potency of the best natural Nav1.7 peptide blockers. Finally, subsequent in vivo testing revealed that intrathecal injection of PhlTx1 reduces the response of mice to formalin in both the acute pain and inflammation phase without signs of neurotoxicity. PhlTx1 is thus an interesting toxin to investigate Nav1.7 involvement in cellular excitability and pain.
Sébastien Nicolas; Claude Zoukimian; Frank Bosmans; Jérôme Montnach; Sylvie Diochot; Eva Cuypers; Stephan De Waard; Rémy Béroud; Dietrich Mebs; David Craik; Didier Boturyn; Michel Lazdunski; Jan Tytgat; Michel De Waard. Chemical Synthesis, Proper Folding, Nav Channel Selectivity Profile and Analgesic Properties of the Spider Peptide Phlotoxin 1. Toxins 2019, 11, 367 .
AMA StyleSébastien Nicolas, Claude Zoukimian, Frank Bosmans, Jérôme Montnach, Sylvie Diochot, Eva Cuypers, Stephan De Waard, Rémy Béroud, Dietrich Mebs, David Craik, Didier Boturyn, Michel Lazdunski, Jan Tytgat, Michel De Waard. Chemical Synthesis, Proper Folding, Nav Channel Selectivity Profile and Analgesic Properties of the Spider Peptide Phlotoxin 1. Toxins. 2019; 11 (6):367.
Chicago/Turabian StyleSébastien Nicolas; Claude Zoukimian; Frank Bosmans; Jérôme Montnach; Sylvie Diochot; Eva Cuypers; Stephan De Waard; Rémy Béroud; Dietrich Mebs; David Craik; Didier Boturyn; Michel Lazdunski; Jan Tytgat; Michel De Waard. 2019. "Chemical Synthesis, Proper Folding, Nav Channel Selectivity Profile and Analgesic Properties of the Spider Peptide Phlotoxin 1." Toxins 11, no. 6: 367.
Fast inactivation of voltage-gated sodium (Nav) channels is essential for electrical signaling, but its mechanism remains poorly understood. Here we determined the structures of a eukaryotic Nav channel alone and in complex with a lethal α-scorpion toxin, AaH2, by electron microscopy, both at 3.5-angstrom resolution. AaH2 wedges into voltage-sensing domain IV (VSD4) to impede fast activation by trapping a deactivated state in which gating charge interactions bridge to the acidic intracellular carboxyl-terminal domain. In the absence of AaH2, the S4 helix of VSD4 undergoes a ~13-angstrom translation to unlatch the intracellular fast-inactivation gating machinery. Highlighting the polypharmacology of α-scorpion toxins, AaH2 also targets an unanticipated receptor site on VSD1 and a pore glycan adjacent to VSD4. Overall, this work provides key insights into fast inactivation, electromechanical coupling, and pathogenic mutations in Nav channels.
Thomas Clairfeuille; Alexander Cloake; Daniel T. Infield; José P. Llongueras; Christopher P. Arthur; Zhong Rong Li; Yuwen Jian; Marie-France Martin-Eauclaire; Pierre E. Bougis; Claudio Ciferri; Christopher A. Ahern; Frank Bosmans; David H. Hackos; Alexis Rohou; Jian Payandeh. Structural basis of α-scorpion toxin action on Nav channels. Science 2019, 363, eaav8573 .
AMA StyleThomas Clairfeuille, Alexander Cloake, Daniel T. Infield, José P. Llongueras, Christopher P. Arthur, Zhong Rong Li, Yuwen Jian, Marie-France Martin-Eauclaire, Pierre E. Bougis, Claudio Ciferri, Christopher A. Ahern, Frank Bosmans, David H. Hackos, Alexis Rohou, Jian Payandeh. Structural basis of α-scorpion toxin action on Nav channels. Science. 2019; 363 (6433):eaav8573.
Chicago/Turabian StyleThomas Clairfeuille; Alexander Cloake; Daniel T. Infield; José P. Llongueras; Christopher P. Arthur; Zhong Rong Li; Yuwen Jian; Marie-France Martin-Eauclaire; Pierre E. Bougis; Claudio Ciferri; Christopher A. Ahern; Frank Bosmans; David H. Hackos; Alexis Rohou; Jian Payandeh. 2019. "Structural basis of α-scorpion toxin action on Nav channels." Science 363, no. 6433: eaav8573.
Itch (pruritis) and pain represent two distinct sensory modalities; yet both have evolved to alert us to potentially harmful external stimuli. Compared with pain, our understanding of itch is still nascent. Here, we report a new clinical case of debilitating itch and altered pain perception resulting from the heterozygous de novo p.L811P gain-of-function mutation in NaV1.9, a voltage-gated sodium (NaV) channel subtype that relays sensory information from the periphery to the spine. To investigate the role of NaV1.9 in itch, we developed a mouse line in which the channel is N-terminally tagged with a fluorescent protein, thereby enabling the reliable identification and biophysical characterization of NaV1.9-expressing neurons. We also assessed NaV1.9 involvement in itch by using a newly created NaV1.9-/- and NaV1.9L799P/WT mouse model. We found that NaV1.9 is expressed in a subset of nonmyelinated, nonpeptidergic small-diameter dorsal root ganglia (DRGs). In WT DRGs, but not those of NaV1.9-/- mice, pruritogens altered action potential parameters and NaV channel gating properties. Additionally, NaV1.9-/- mice exhibited a strong reduction in acute scratching behavior in response to pruritogens, whereas NaV1.9L799P/WT mice displayed increased spontaneous scratching. Altogether, our data suggest an important contribution of NaV1.9 to itch signaling.
Juan Salvatierra; Marcelo Diaz-Bustamante; James Meixiong; Elaine Tierney; Xinzhong Dong; Frank Bosmans. A disease mutation reveals a role for NaV1.9 in acute itch. Journal of Clinical Investigation 2018, 128, 5434 -5447.
AMA StyleJuan Salvatierra, Marcelo Diaz-Bustamante, James Meixiong, Elaine Tierney, Xinzhong Dong, Frank Bosmans. A disease mutation reveals a role for NaV1.9 in acute itch. Journal of Clinical Investigation. 2018; 128 (12):5434-5447.
Chicago/Turabian StyleJuan Salvatierra; Marcelo Diaz-Bustamante; James Meixiong; Elaine Tierney; Xinzhong Dong; Frank Bosmans. 2018. "A disease mutation reveals a role for NaV1.9 in acute itch." Journal of Clinical Investigation 128, no. 12: 5434-5447.
Marie-France Martin-Eauclaire; Juan Salvatierra; Pascal Mansuelle; Frank Bosmans; Pierre E. Bougis. The scorpion toxin Bot IX is a potent member of the α‐like family and has a unique N‐terminal sequence extension. FEBS Letters 2018, 592, 2668 -2668.
AMA StyleMarie-France Martin-Eauclaire, Juan Salvatierra, Pascal Mansuelle, Frank Bosmans, Pierre E. Bougis. The scorpion toxin Bot IX is a potent member of the α‐like family and has a unique N‐terminal sequence extension. FEBS Letters. 2018; 592 (15):2668-2668.
Chicago/Turabian StyleMarie-France Martin-Eauclaire; Juan Salvatierra; Pascal Mansuelle; Frank Bosmans; Pierre E. Bougis. 2018. "The scorpion toxin Bot IX is a potent member of the α‐like family and has a unique N‐terminal sequence extension." FEBS Letters 592, no. 15: 2668-2668.
Functional bowel disorder patients can suffer from chronic abdominal pain, likely due to visceral hypersensitivity to mechanical stimuli. As there is only a limited understanding of the basis of chronic visceral hypersensitivity (CVH), drug-based management strategies are ill defined, vary considerably, and include NSAIDs, opioids, and even anticonvulsants. We previously reported that the 1.1 subtype of the voltage-gated sodium (NaV; NaV1.1) channel family regulates the excitability of sensory nerve fibers that transmit a mechanical pain message to the spinal cord. Herein, we investigated whether this channel subtype also underlies the abdominal pain that occurs with CVH. We demonstrate that NaV1.1 is functionally upregulated under CVH conditions and that inhibiting channel function reduces mechanical pain in 3 mechanistically distinct mouse models of chronic pain. In particular, we use a small molecule to show that selective NaV1.1 inhibition (a) decreases sodium currents in colon-innervating dorsal root ganglion neurons, (b) reduces colonic nociceptor mechanical responses, and (c) normalizes the enhanced visceromotor response to distension observed in 2 mouse models of irritable bowel syndrome. These results provide support for a relationship between NaV1.1 and chronic abdominal pain associated with functional bowel disorders.
Juan Salvatierra; Joel Castro; Andelain Erickson; Qian Li; Joao Braz; John Gilchrist; Luke Grundy; Grigori Rychkov; Annemie Deiteren; Rana Rais; Glenn King; Barbara S. Slusher; Allan Basbaum; Pankaj J. Pasricha; Stuart M. Brierley; Frank Bosmans. NaV1.1 inhibition can reduce visceral hypersensitivity. JCI Insight 2018, 3, 1 .
AMA StyleJuan Salvatierra, Joel Castro, Andelain Erickson, Qian Li, Joao Braz, John Gilchrist, Luke Grundy, Grigori Rychkov, Annemie Deiteren, Rana Rais, Glenn King, Barbara S. Slusher, Allan Basbaum, Pankaj J. Pasricha, Stuart M. Brierley, Frank Bosmans. NaV1.1 inhibition can reduce visceral hypersensitivity. JCI Insight. 2018; 3 (11):1.
Chicago/Turabian StyleJuan Salvatierra; Joel Castro; Andelain Erickson; Qian Li; Joao Braz; John Gilchrist; Luke Grundy; Grigori Rychkov; Annemie Deiteren; Rana Rais; Glenn King; Barbara S. Slusher; Allan Basbaum; Pankaj J. Pasricha; Stuart M. Brierley; Frank Bosmans. 2018. "NaV1.1 inhibition can reduce visceral hypersensitivity." JCI Insight 3, no. 11: 1.
Gating pore currents through the voltage-sensing domains (VSDs) of the skeletal muscle voltage-gated sodium channel NaV1.4 underlie hypokalemic periodic paralysis (HypoPP) type 2. Gating modifier toxins target ion channels by modifying the function of the VSDs. We tested the hypothesis that these toxins could function as blockers of the pathogenic gating pore currents. We report that a crab spider toxin Hm-3 from Heriaeus melloteei can inhibit gating pore currents due to mutations affecting the second arginine residue in the S4 helix of VSD-I that we have found in patients with HypoPP and describe here. NMR studies show that Hm-3 partitions into micelles through a hydrophobic cluster formed by aromatic residues and reveal complex formation with VSD-I through electrostatic and hydrophobic interactions with the S3b helix and the S3–S4 extracellular loop. Our data identify VSD-I as a specific binding site for neurotoxins on sodium channels. Gating modifier toxins may constitute useful hits for the treatment of HypoPP.
Roope Männikkö; Zakhar O. Shenkarev; Michael G. Thor; Antonina A. Berkut; Mikhail Yu Myshkin; Alexander S. Paramonov; Dmitrii S. Kulbatskii; Dmitry A. Kuzmin; Marisol Sampedro Castaneda; Louise King; Emma Wilson; Ekaterina N. Lyukmanova; Mikhail Kirpichnikov; Stephanie Schorge; Frank Bosmans; Michael G. Hanna; Dimitri M. Kullmann; Alexander A. Vassilevski. Spider toxin inhibits gating pore currents underlying periodic paralysis. Proceedings of the National Academy of Sciences 2018, 115, 4495 -4500.
AMA StyleRoope Männikkö, Zakhar O. Shenkarev, Michael G. Thor, Antonina A. Berkut, Mikhail Yu Myshkin, Alexander S. Paramonov, Dmitrii S. Kulbatskii, Dmitry A. Kuzmin, Marisol Sampedro Castaneda, Louise King, Emma Wilson, Ekaterina N. Lyukmanova, Mikhail Kirpichnikov, Stephanie Schorge, Frank Bosmans, Michael G. Hanna, Dimitri M. Kullmann, Alexander A. Vassilevski. Spider toxin inhibits gating pore currents underlying periodic paralysis. Proceedings of the National Academy of Sciences. 2018; 115 (17):4495-4500.
Chicago/Turabian StyleRoope Männikkö; Zakhar O. Shenkarev; Michael G. Thor; Antonina A. Berkut; Mikhail Yu Myshkin; Alexander S. Paramonov; Dmitrii S. Kulbatskii; Dmitry A. Kuzmin; Marisol Sampedro Castaneda; Louise King; Emma Wilson; Ekaterina N. Lyukmanova; Mikhail Kirpichnikov; Stephanie Schorge; Frank Bosmans; Michael G. Hanna; Dimitri M. Kullmann; Alexander A. Vassilevski. 2018. "Spider toxin inhibits gating pore currents underlying periodic paralysis." Proceedings of the National Academy of Sciences 115, no. 17: 4495-4500.
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 (NaV1.2). By doing so, we observe that in NaV1.8, 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. This article is protected by copyright. All rights reserved
John Gilchrist; Frank Bosmans. Using voltage-sensor toxins and their molecular targets to investigate NaV 1.8 gating. The Journal of Physiology 2018, 596, 1863 -1872.
AMA StyleJohn Gilchrist, Frank Bosmans. Using voltage-sensor toxins and their molecular targets to investigate NaV 1.8 gating. The Journal of Physiology. 2018; 596 (10):1863-1872.
Chicago/Turabian StyleJohn Gilchrist; Frank Bosmans. 2018. "Using voltage-sensor toxins and their molecular targets to investigate NaV 1.8 gating." The Journal of Physiology 596, no. 10: 1863-1872.
The Nav1.1 voltage-gated sodium channel is a critical contributor to excitability in the brain, where pathological loss of function leads to such disorders as epilepsy, Alzheimer’s disease, and autism. This voltage-gated sodium (Nav) channel subtype also plays an important role in mechanical pain signaling by primary afferent somatosensory neurons. Therefore, pharmacologic modulation of Nav1.1 represents a potential strategy for treating excitability disorders of the brain and periphery. Inactivation is a complex aspect of Nav channel gating and consists of fast and slow components, each of which may involve a contribution from one or more voltage-sensing domains. Here, we exploit the Hm1a spider toxin, a Nav1.1-selective modulator, to better understand the relationship between these temporally distinct modes of inactivation and ask whether they can be distinguished pharmacologically. We show that Hm1a inhibits the gating movement of the domain IV voltage sensor (VSDIV), hindering both fast and slow inactivation and leading to an increase in Nav1.1 availability during high-frequency stimulation. In contrast, ICA-121431, a small-molecule Nav1.1 inhibitor, accelerates a subsequent VSDIV gating transition to accelerate entry into the slow inactivated state, resulting in use-dependent block. Further evidence for functional coupling between fast and slow inactivation is provided by a Nav1.1 mutant in which fast inactivation removal has complex effects on slow inactivation. Taken together, our data substantiate the key role of VSDIV in Nav channel fast and slow inactivation and demonstrate that these gating processes are sequential and coupled through VSDIV. These findings provide insight into a pharmacophore on VSDIV through which modulation of inactivation gating can inhibit or facilitate Nav1.1 function.
Jeremiah D. Osteen; Kevin Sampson; Vivek Iyer; David Julius; Frank Bosmans. Pharmacology of the Na v 1.1 domain IV voltage sensor reveals coupling between inactivation gating processes. Proceedings of the National Academy of Sciences 2017, 114, 201621263 -6841.
AMA StyleJeremiah D. Osteen, Kevin Sampson, Vivek Iyer, David Julius, Frank Bosmans. Pharmacology of the Na v 1.1 domain IV voltage sensor reveals coupling between inactivation gating processes. Proceedings of the National Academy of Sciences. 2017; 114 (26):201621263-6841.
Chicago/Turabian StyleJeremiah D. Osteen; Kevin Sampson; Vivek Iyer; David Julius; Frank Bosmans. 2017. "Pharmacology of the Na v 1.1 domain IV voltage sensor reveals coupling between inactivation gating processes." Proceedings of the National Academy of Sciences 114, no. 26: 201621263-6841.
Voltage-gated sodium (NaV) channels are responsible for the initiation and conduction of action potentials within primary afferents. The nine NaV channel isoforms recognized in mammals are often functionally divided into tetrodotoxin (TTX)-sensitive (TTX-s) channels (NaV1.1–NaV1.4, NaV1.6–NaV1.7) that are blocked by nanomolar concentrations and TTX-resistant (TTX-r) channels (NaV1.8 and NaV1.9) inhibited by millimolar concentrations, with NaV1.5 having an intermediate toxin sensitivity. For small-diameter primary afferent neurons, it is unclear to what extent different NaV channel isoforms are distributed along the peripheral and central branches of their bifurcated axons. To determine the relative contribution of TTX-s and TTX-r channels to action potential conduction in different axonal compartments, we investigated the effects of TTX on C-fiber-mediated compound action potentials (C-CAPs) of proximal and distal peripheral nerve segments and dorsal roots from mice and pigtail monkeys (Macaca nemestrina). In the dorsal roots and proximal peripheral nerves of mice and nonhuman primates, TTX reduced the C-CAP amplitude to 16% of the baseline. In contrast, >30% of the C-CAP was resistant to TTX in distal peripheral branches of monkeys and WT and NaV1.9−/− mice. In nerves from NaV1.8−/− mice, TTX-r C-CAPs could not be detected. These data indicate that NaV1.8 is the primary isoform underlying TTX-r conduction in distal axons of somatosensory C-fibers. Furthermore, there is a differential spatial distribution of NaV1.8 within C-fiber axons, being functionally more prominent in the most distal axons and terminal regions. The enrichment of NaV1.8 in distal axons may provide a useful target in the treatment of pain of peripheral origin. SIGNIFICANCE STATEMENT It is unclear whether individual sodium channel isoforms exert differential roles in action potential conduction along the axonal membrane of nociceptive, unmyelinated peripheral nerve fibers, but clarifying the role of sodium channel subtypes in different axonal segments may be useful for the development of novel analgesic strategies. Here, we provide evidence from mice and nonhuman primates that a substantial portion of the C-fiber compound action potential in distal peripheral nerves, but not proximal nerves or dorsal roots, is resistant to tetrodotoxin and that, in mice, this effect is mediated solely by voltage-gated sodium channel 1.8 (NaV1.8). The functional prominence of NaV1.8 within the axonal compartment immediately proximal to its termination may affect strategies targeting pain of peripheral origin.
Amanda H. Klein; Alina Vyshnevska; Timothy V. Hartke; Roberto De Col; Joseph L. Mankowski; Brian Turnquist; Frank Bosmans; Peter W. Reeh; Martin Schmelz; Richard W. Carr; Matthias Ringkamp. Sodium Channel Nav1.8 Underlies TTX-Resistant Axonal Action Potential Conduction in Somatosensory C-Fibers of Distal Cutaneous Nerves. The Journal of Neuroscience 2017, 37, 5204 -5214.
AMA StyleAmanda H. Klein, Alina Vyshnevska, Timothy V. Hartke, Roberto De Col, Joseph L. Mankowski, Brian Turnquist, Frank Bosmans, Peter W. Reeh, Martin Schmelz, Richard W. Carr, Matthias Ringkamp. Sodium Channel Nav1.8 Underlies TTX-Resistant Axonal Action Potential Conduction in Somatosensory C-Fibers of Distal Cutaneous Nerves. The Journal of Neuroscience. 2017; 37 (20):5204-5214.
Chicago/Turabian StyleAmanda H. Klein; Alina Vyshnevska; Timothy V. Hartke; Roberto De Col; Joseph L. Mankowski; Brian Turnquist; Frank Bosmans; Peter W. Reeh; Martin Schmelz; Richard W. Carr; Matthias Ringkamp. 2017. "Sodium Channel Nav1.8 Underlies TTX-Resistant Axonal Action Potential Conduction in Somatosensory C-Fibers of Distal Cutaneous Nerves." The Journal of Neuroscience 37, no. 20: 5204-5214.
Voltage-gated sodium (NaV) channels are essential for the transmission of pain signals in humans making them prime targets for the development of new analgesics. Spider venoms are a rich source of peptide modulators useful to study ion channel structure and function. Here we describe β/δ-TRTX-Pre1a, a 35-residue tarantula peptide that selectively interacts with neuronal NaV channels inhibiting peak current of hNaV1.1, rNaV1.2, hNaV1.6, and hNaV1.7 while concurrently inhibiting fast inactivation of hNaV1.1 and rNaV1.3. The DII and DIV S3-S4 loops of NaV channel voltage sensors are important for the interaction of Pre1a with NaV channels but cannot account for its unique subtype selectivity. Through analysis of the binding regions we ascertained that the variability of the S1-S2 loops between NaV channels contributes substantially to the selectivity profile observed for Pre1a, particularly with regards to fast inactivation. A serine residue on the DIV S2 helix was found to be sufficient to explain Pre1a's potent and selective inhibitory effect on the fast inactivation process of NaV1.1 and 1.3. This work highlights that interactions with both S1-S2 and S3-S4 of NaV channels may be necessary for functional modulation, and that targeting the diverse S1-S2 region within voltage-sensing domains provides an avenue to develop subtype selective tools.
Joshua S. Wingerd; Christine A. Mozar; Christine A. Ussing; Swetha S. Murali; Yanni K.-Y. Chin; Ben Cristofori-Armstrong; Thomas Durek; John Gilchrist; Christopher W. Vaughan; Frank Bosmans; David J. Adams; Richard J. Lewis; Paul F. Alewood; Mehdi Mobli; Macdonald J. Christie; Lachlan D. Rash. The tarantula toxin β/δ-TRTX-Pre1a highlights the importance of the S1-S2 voltage-sensor region for sodium channel subtype selectivity. Scientific Reports 2017, 7, 974 .
AMA StyleJoshua S. Wingerd, Christine A. Mozar, Christine A. Ussing, Swetha S. Murali, Yanni K.-Y. Chin, Ben Cristofori-Armstrong, Thomas Durek, John Gilchrist, Christopher W. Vaughan, Frank Bosmans, David J. Adams, Richard J. Lewis, Paul F. Alewood, Mehdi Mobli, Macdonald J. Christie, Lachlan D. Rash. The tarantula toxin β/δ-TRTX-Pre1a highlights the importance of the S1-S2 voltage-sensor region for sodium channel subtype selectivity. Scientific Reports. 2017; 7 (1):974.
Chicago/Turabian StyleJoshua S. Wingerd; Christine A. Mozar; Christine A. Ussing; Swetha S. Murali; Yanni K.-Y. Chin; Ben Cristofori-Armstrong; Thomas Durek; John Gilchrist; Christopher W. Vaughan; Frank Bosmans; David J. Adams; Richard J. Lewis; Paul F. Alewood; Mehdi Mobli; Macdonald J. Christie; Lachlan D. Rash. 2017. "The tarantula toxin β/δ-TRTX-Pre1a highlights the importance of the S1-S2 voltage-sensor region for sodium channel subtype selectivity." Scientific Reports 7, no. 1: 974.
Human genetic studies have implicated the voltage-gated sodium channel NaV1.7 as a therapeutic target for the treatment of pain. A novel peptide, μ-theraphotoxin-Pn3a, isolated from venom of the tarantula Pamphobeteus nigricolor, potently inhibits NaV1.7 (IC50 0.9 nM) with at least 40–1000-fold selectivity over all other NaV subtypes. Despite on-target activity in small-diameter dorsal root ganglia, spinal slices, and in a mouse model of pain induced by NaV1.7 activation, Pn3a alone displayed no analgesic activity in formalin-, carrageenan- or FCA-induced pain in rodents when administered systemically. A broad lack of analgesic activity was also found for the selective NaV1.7 inhibitors PF-04856264 and phlotoxin 1. However, when administered with subtherapeutic doses of opioids or the enkephalinase inhibitor thiorphan, these subtype-selective NaV1.7 inhibitors produced profound analgesia. Our results suggest that in these inflammatory models, acute administration of peripherally restricted NaV1.7 inhibitors can only produce analgesia when administered in combination with an opioid.
Jennifer Deuis; Zoltan Dekan; Joshua S. Wingerd; Jennifer Smith; Nehan R. Munasinghe; Rebecca F. Bhola; Wendy Imlach; Volker Herzig; David A. Armstrong; K. Johan Rosengren; Frank Bosmans; Stephen G. Waxman; Sulayman D. Dib-Hajj; Pierre Escoubas; Michael S. Minett; Macdonald J. Christie; Glenn King; Paul Alewood; Richard Lewis; John N. Wood; Irina Vetter. Pharmacological characterisation of the highly NaV1.7 selective spider venom peptide Pn3a. Scientific Reports 2017, 7, 40883 .
AMA StyleJennifer Deuis, Zoltan Dekan, Joshua S. Wingerd, Jennifer Smith, Nehan R. Munasinghe, Rebecca F. Bhola, Wendy Imlach, Volker Herzig, David A. Armstrong, K. Johan Rosengren, Frank Bosmans, Stephen G. Waxman, Sulayman D. Dib-Hajj, Pierre Escoubas, Michael S. Minett, Macdonald J. Christie, Glenn King, Paul Alewood, Richard Lewis, John N. Wood, Irina Vetter. Pharmacological characterisation of the highly NaV1.7 selective spider venom peptide Pn3a. Scientific Reports. 2017; 7 (1):40883.
Chicago/Turabian StyleJennifer Deuis; Zoltan Dekan; Joshua S. Wingerd; Jennifer Smith; Nehan R. Munasinghe; Rebecca F. Bhola; Wendy Imlach; Volker Herzig; David A. Armstrong; K. Johan Rosengren; Frank Bosmans; Stephen G. Waxman; Sulayman D. Dib-Hajj; Pierre Escoubas; Michael S. Minett; Macdonald J. Christie; Glenn King; Paul Alewood; Richard Lewis; John N. Wood; Irina Vetter. 2017. "Pharmacological characterisation of the highly NaV1.7 selective spider venom peptide Pn3a." Scientific Reports 7, no. 1: 40883.
Sheep flystrike is caused by parasitic flies laying eggs on soiled wool or open wounds, after which the hatched maggots feed on the sheep flesh and often cause large lesions. It is a significant economic problem for the livestock industry as infestations are difficult to control due to ongoing cycles of larval development into flies followed by further egg laying. We therefore screened venom fractions from the Australian theraphosid spider Coremiocnemis tropix to identify toxins active against the sheep blowfly Lucilia cuprina, which is the primary cause of flystrike in Australia. This screen led to isolation of two insecticidal peptides, Ct1a and Ct1b, that are lethal to blowflies within 24 h of injection. The primary structure of these peptides was determined using a combination of Edman degradation and sequencing of a C. tropix venom-gland transcriptome. Ct1a and Ct1b contain 39 and 38 amino acid residues, respectively, including six cysteine residues that form three disulfide bonds. Recombinant production in bacteria (Escherichia coli) resulted in low yields of Ct1a whereas solid-phase peptide synthesis using native chemical ligation produced sufficient quantities of Ct1a for functional analyses. Synthetic Ct1a had no effect on voltage-gated sodium channels from the American cockroach Periplanata americana or the German cockroach Blattella germanica, but it was lethal to sheep blowflies with an LD50 of 1687 pmol/g.
Maria Ikonomopoulou; Jennifer Smith; Volker Herzig; Sandy S. Pineda; Sławomir Dziemborowicz; Sing-Yan Er; Thomas Durek; John Gilchrist; Paul F. Alewood; Graham Nicholson; Frank Bosmans; Glenn F. King. Isolation of two insecticidal toxins from venom of the Australian theraphosid spider Coremiocnemis tropix. Toxicon 2016, 123, 62 -70.
AMA StyleMaria Ikonomopoulou, Jennifer Smith, Volker Herzig, Sandy S. Pineda, Sławomir Dziemborowicz, Sing-Yan Er, Thomas Durek, John Gilchrist, Paul F. Alewood, Graham Nicholson, Frank Bosmans, Glenn F. King. Isolation of two insecticidal toxins from venom of the Australian theraphosid spider Coremiocnemis tropix. Toxicon. 2016; 123 ():62-70.
Chicago/Turabian StyleMaria Ikonomopoulou; Jennifer Smith; Volker Herzig; Sandy S. Pineda; Sławomir Dziemborowicz; Sing-Yan Er; Thomas Durek; John Gilchrist; Paul F. Alewood; Graham Nicholson; Frank Bosmans; Glenn F. King. 2016. "Isolation of two insecticidal toxins from venom of the Australian theraphosid spider Coremiocnemis tropix." Toxicon 123, no. : 62-70.
Voltage-gated sodium (Nav) channels initiate action potentials in most neurons, including primary afferent nerve fibres of the pain pathway. Local anaesthetics block pain through non-specific actions at all Nav channels, but the discovery of selective modulators would facilitate the analysis of individual subtypes of these channels and their contributions to chemical, mechanical, or thermal pain. Here we identify and characterize spider (Heteroscodra maculata) toxins that selectively activate the Nav1.1 subtype, the role of which in nociception and pain has not been elucidated. We use these probes to show that Nav1.1-expressing fibres are modality-specific nociceptors: their activation elicits robust pain behaviours without neurogenic inflammation and produces profound hypersensitivity to mechanical, but not thermal, stimuli. In the gut, high-threshold mechanosensitive fibres also express Nav1.1 and show enhanced toxin sensitivity in a mouse model of irritable bowel syndrome. Together, these findings establish an unexpected role for Nav1.1 channels in regulating the excitability of sensory nerve fibres that mediate mechanical pain. Two spider toxins are shown to target the Nav1.1 subtype of sodium channel specifically, shedding light on the role of these channels in mechanical pain signalling. Mutations affecting several Nav1 subtype voltage-gated sodium channels have been shown to be associated with insensitivity to pain or persistent pain syndromes. Nav1.1 is expressed by somatosensory neurons, but no direct link has been established between this subtype and nociception. Further studies have been hampered by a paucity of pharmacological agents that discriminate between the closely related members of the Nav1 family. Now David Julius and colleagues have identified two spider toxins specifically targeting Nav1.1, and use them to show that this channel is key to the specific transduction of mechanical but not thermal pain by myelinated Aδ sensory fibres. Previous genetic studies of Nav1.1 indicate that such selective agents may open therapeutic avenues in disorders associated with the central nervous system, such as epilepsy, autism and Alzheimer disease. The involvement of Nav1.1 channels in mediating mechanical pain reported here was unexpected.
Jeremiah D. Osteen; Volker Herzig; John Gilchrist; Joshua J. Emrick; Chuchu Zhang; Xidao Wang; Joel Castro; Sonia Garcia-Caraballo; Luke Grundy; Grigori Y. Rychkov; Andy D. Weyer; Zoltan Dekan; Eivind A. B. Undheim; Paul Alewood; Cheryl L. Stucky; Stuart M. Brierley; Allan I. Basbaum; Frank Bosmans; Glenn F. King; David Julius. Selective spider toxins reveal a role for the Nav1.1 channel in mechanical pain. Nature 2016, 534, 494 -499.
AMA StyleJeremiah D. Osteen, Volker Herzig, John Gilchrist, Joshua J. Emrick, Chuchu Zhang, Xidao Wang, Joel Castro, Sonia Garcia-Caraballo, Luke Grundy, Grigori Y. Rychkov, Andy D. Weyer, Zoltan Dekan, Eivind A. B. Undheim, Paul Alewood, Cheryl L. Stucky, Stuart M. Brierley, Allan I. Basbaum, Frank Bosmans, Glenn F. King, David Julius. Selective spider toxins reveal a role for the Nav1.1 channel in mechanical pain. Nature. 2016; 534 (7608):494-499.
Chicago/Turabian StyleJeremiah D. Osteen; Volker Herzig; John Gilchrist; Joshua J. Emrick; Chuchu Zhang; Xidao Wang; Joel Castro; Sonia Garcia-Caraballo; Luke Grundy; Grigori Y. Rychkov; Andy D. Weyer; Zoltan Dekan; Eivind A. B. Undheim; Paul Alewood; Cheryl L. Stucky; Stuart M. Brierley; Allan I. Basbaum; Frank Bosmans; Glenn F. King; David Julius. 2016. "Selective spider toxins reveal a role for the Nav1.1 channel in mechanical pain." Nature 534, no. 7608: 494-499.
Disulfide‐rich peptides isolated from cone snails are of great interest as drug leads due to their high specificity and potency toward therapeutically relevant ion channels and receptors. They commonly contain the inhibitor cystine knot (ICK) motif comprising three disulfide bonds forming a knotted core. Here we report the successful enzymatic backbone cyclization of an ICK‐containing peptide κ‐PVIIA, a 27‐amino acid conopeptide from Conus purpurascens, using a mutated version of the bacterial transpeptidase, sortase A. Although a slight loss of activity was observed compared to native κ‐PVIIA, cyclic κ‐PVIIA is a functional peptide that inhibits the Shaker voltage‐gated potassium (Kv) channel. Molecular modeling suggests that the decrease in potency may be related to the loss of crucial, but previously unidentified electrostatic interactions between the N‐terminus of the peptide and the Shaker channel. This hypothesis was confirmed by testing an N‐terminally acetylated κ‐PVIIA, which shows a similar decrease in activity. We also investigated the conformational dynamics and hydrogen bond network of cyc‐PVIIA, both of which are important factors to be considered for successful cyclization of peptides. We found that cyc‐PVIIA has the same conformational dynamics, but different hydrogen bond network compared to those of κ‐PVIIA. The ability to efficiently cyclize ICK peptides using sortase A will enable future protein engineering for this class of peptides and may help in the development of novel therapeutic molecules. Biotechnol. Bioeng. 2016;113: 2202–2212.
Soohyun Kwon; Frank Bosmans; Quentin Kaas; Olivier Cheneval; Anne C. Conibear; K. Johan Rosengren; Conan K. Wang; Christina I. Schroeder; David J. Craik. Efficient enzymatic cyclization of an inhibitory cystine knot‐containing peptide. Biotechnology and Bioengineering 2016, 113, 2202 -2212.
AMA StyleSoohyun Kwon, Frank Bosmans, Quentin Kaas, Olivier Cheneval, Anne C. Conibear, K. Johan Rosengren, Conan K. Wang, Christina I. Schroeder, David J. Craik. Efficient enzymatic cyclization of an inhibitory cystine knot‐containing peptide. Biotechnology and Bioengineering. 2016; 113 (10):2202-2212.
Chicago/Turabian StyleSoohyun Kwon; Frank Bosmans; Quentin Kaas; Olivier Cheneval; Anne C. Conibear; K. Johan Rosengren; Conan K. Wang; Christina I. Schroeder; David J. Craik. 2016. "Efficient enzymatic cyclization of an inhibitory cystine knot‐containing peptide." Biotechnology and Bioengineering 113, no. 10: 2202-2212.
Chronic pain is a serious worldwide health issue, with current analgesics having limited efficacy and dose-limiting side effects. Humans with loss-of-function mutations in the voltage-gated sodium channel NaV1.7 (hNaV1.7) are indifferent to pain, making hNaV1.7 a promising target for analgesic development. Since spider venoms are replete with NaV channel modulators, we examined their potential as a source of hNaV1.7 inhibitors. We developed a high-throughput fluorescent-based assay to screen spider venoms against hNaV1.7 and isolate ‘hit’ peptides. To examine the binding site of these peptides, we constructed a panel of chimeric channels in which the S3b-S4 paddle motif from each voltage sensor domain of hNaV1.7 was transplanted into the homotetrameric KV2.1 channel. We screened 205 spider venoms and found that 40% contain at least one inhibitor of hNaV1.7. By deconvoluting ‘hit’ venoms, we discovered seven novel members of the NaSpTx family 1. One of these peptides, Hd1a (peptide μ-TRTX-Hd1a from venom of the spider Haplopelma doriae), inhibited hNaV1.7 with a high level of selectivity over all other subtypes, except hNaV1.1. We showed that Hd1a is a gating modifier that inhibits hNaV1.7 by interacting with the S3b-S4 paddle motif in channel domain II. The structure of Hd1a, determined using heteronuclear NMR, contains an inhibitor cystine knot motif that is likely to confer high levels of chemical, thermal and biological stability. Our data indicate that spider venoms are a rich natural source of hNaV1.7 inhibitors that might be useful leads for the development of novel analgesics.
Julie K Klint; Jennifer J Smith; Irina Vetter; Darshani B Rupasinghe; Sing Yan Er; Sebastian Senff; Volker Herzig; Mehdi Mobli; Richard J Lewis; Frank Bosmans; Glenn F King. Seven novel modulators of the analgesic target NaV 1.7 uncovered using a high-throughput venom-based discovery approach. Journal of Cerebral Blood Flow & Metabolism 2015, 172, 2445 -2458.
AMA StyleJulie K Klint, Jennifer J Smith, Irina Vetter, Darshani B Rupasinghe, Sing Yan Er, Sebastian Senff, Volker Herzig, Mehdi Mobli, Richard J Lewis, Frank Bosmans, Glenn F King. Seven novel modulators of the analgesic target NaV 1.7 uncovered using a high-throughput venom-based discovery approach. Journal of Cerebral Blood Flow & Metabolism. 2015; 172 (10):2445-2458.
Chicago/Turabian StyleJulie K Klint; Jennifer J Smith; Irina Vetter; Darshani B Rupasinghe; Sing Yan Er; Sebastian Senff; Volker Herzig; Mehdi Mobli; Richard J Lewis; Frank Bosmans; Glenn F King. 2015. "Seven novel modulators of the analgesic target NaV 1.7 uncovered using a high-throughput venom-based discovery approach." Journal of Cerebral Blood Flow & Metabolism 172, no. 10: 2445-2458.
Animal toxins that inhibit voltage-gated sodium (Nav) channel fast inactivation can do so through an interaction with the S3b–S4 helix-turn-helix region, or paddle motif, located in the domain IV voltage sensor. Here, we used surface plasmon resonance (SPR), an optical approach that uses polarized light to measure the refractive index near a sensor surface to which a molecule of interest is attached, to analyze interactions between the isolated domain IV paddle and Nav channel–selective α-scorpion toxins. Our SPR analyses showed that the domain IV paddle can be removed from the Nav channel and immobilized on sensor chips, and suggest that the isolated motif remains susceptible to animal toxins that target the domain IV voltage sensor. As such, our results uncover the inherent pharmacological sensitivities of the isolated domain IV paddle motif, which may be exploited to develop a label-free SPR approach for discovering ligands that target this region.
Marie-France Martin-Eauclaire; Géraldine Ferracci; Frank Bosmans; Pierre E. Bougis. A surface plasmon resonance approach to monitor toxin interactions with an isolated voltage-gated sodium channel paddle motif. Journal of General Physiology 2015, 145, 155 -162.
AMA StyleMarie-France Martin-Eauclaire, Géraldine Ferracci, Frank Bosmans, Pierre E. Bougis. A surface plasmon resonance approach to monitor toxin interactions with an isolated voltage-gated sodium channel paddle motif. Journal of General Physiology. 2015; 145 (2):155-162.
Chicago/Turabian StyleMarie-France Martin-Eauclaire; Géraldine Ferracci; Frank Bosmans; Pierre E. Bougis. 2015. "A surface plasmon resonance approach to monitor toxin interactions with an isolated voltage-gated sodium channel paddle motif." Journal of General Physiology 145, no. 2: 155-162.