scholarly journals Phosphorylation of a chronic pain mutation in the voltage-gated sodium channel Nav1.7 increases voltage sensitivity

2020 ◽  
pp. jbc.RA120.014288
Author(s):  
Clara M Kerth ◽  
Petra Hautvast ◽  
Jannis Körner ◽  
Angelika Lampert ◽  
Jannis E Meents
Keyword(s):  
Chronic Pain ◽  
Kinase Inhibitors ◽  
Treatment Options ◽  
Phosphorylation Site ◽  
Functional Change ◽  
Voltage Sensitivity ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels ◽  
Whole Cell Patch Clamp ◽  
Putative Phosphorylation Site

Mutations in voltage-gated sodium channels (Navs) can cause alterations in pain sensation, such as chronic pain diseases like inherited erythromelalgia (IEM). The IEM-causing mutation Nav1.7 p.I848T is known to induce a hyperpolarized shift in the voltage dependence of activation in Nav1.7. So far, however, the mechanism to explain this increase in voltage sensitivity remains unknown. In the present study, we show that phosphorylation of the newly introduced Thr residue explains the functional change. We expressed either wild type human Nav1.7, the I848T mutant, or other mutations in HEK293T cells and performed whole-cell patch-clamp electrophysiology. As the insertion of a Thr residue potentially creates a novel phosphorylation site for Ser/Thr kinases and because Nav1.7 had been shown in Xenopus oocytes to be affected by protein kinases C (PKC) and A (PKA), we used different non-selective and selective kinase inhibitors and activators to test the effect of phosphorylation on Nav1.7 in a human system. We identify PKC, but not PKA, to be responsible for the phosphorylation of T848 and thereby for the shift in voltage sensitivity. Introducing a negatively charged amino acid instead of the putative phosphorylation site mimics the effect on voltage gating to a lesser extent. 3D modelling using the published cryo-EM structure of human Nav1.7 showed that introduction of this negatively charged site seems to alter the interaction of this residue with surrounding amino acids and thus to influence channel function. These results could provide new opportunities for the development of novel treatment options for chronic pain patients.

scholarly journals Spider Knottin Pharmacology at Voltage-Gated Sodium Channels and Their Potential to Modulate Pain Pathways

Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 626 ◽  
Author(s):  
Yashad Dongol ◽  
Fernanda Caldas Cardoso ◽  
Richard J Lewis
Keyword(s):  
Chronic Pain ◽  
Sodium Channels ◽  
Structural Features ◽  
Voltage Gated ◽  
Subtype Selectivity ◽  
Voltage Gated Sodium Channels ◽  
Neuronal Signalling ◽  
Pain Pathways ◽  
Nav Channels ◽  
Chronic Pain Conditions

Voltage-gated sodium channels (NaVs) are a key determinant of neuronal signalling. Neurotoxins from diverse taxa that selectively activate or inhibit NaV channels have helped unravel the role of NaV channels in diseases, including chronic pain. Spider venoms contain the most diverse array of inhibitor cystine knot (ICK) toxins (knottins). This review provides an overview on how spider knottins modulate NaV channels and describes the structural features and molecular determinants that influence their affinity and subtype selectivity. Genetic and functional evidence support a major involvement of NaV subtypes in various chronic pain conditions. The exquisite inhibitory properties of spider knottins over key NaV subtypes make them the best lead molecules for the development of novel analgesics to treat chronic pain.

scholarly journals Batrachotoxin acts as a stent to hold open homotetrameric prokaryotic voltage-gated sodium channels

2018 ◽  
Vol 151 (2) ◽  
pp. 186-199 ◽  
Author(s):  
Rocio K. Finol-Urdaneta ◽  
Jeffrey R. McArthur ◽  
Marcel P. Goldschen-Ohm ◽  
Rachelle Gaudet ◽  
Denis B. Tikhonov ◽  
...  
Keyword(s):  
Mutational Analysis ◽  
Molecular Model ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels ◽  
Whole Cell Patch Clamp ◽  
Voltage Dependent ◽  
Nav Channels ◽  
Single Polypeptide ◽  
Nerve Muscle

Batrachotoxin (BTX), an alkaloid from skin secretions of dendrobatid frogs, causes paralysis and death by facilitating activation and inhibiting deactivation of eukaryotic voltage-gated sodium (Nav) channels, which underlie action potentials in nerve, muscle, and heart. A full understanding of the mechanism by which BTX modifies eukaryotic Nav gating awaits determination of high-resolution structures of functional toxin–channel complexes. Here, we investigate the action of BTX on the homotetrameric prokaryotic Nav channels NaChBac and NavSp1. By combining mutational analysis and whole-cell patch clamp with molecular and kinetic modeling, we show that BTX hinders deactivation and facilitates activation in a use-dependent fashion. Our molecular model shows the horseshoe-shaped BTX molecule bound within the open pore, forming hydrophobic H-bonds and cation-π contacts with the pore-lining helices, leaving space for partially dehydrated sodium ions to permeate through the hydrophilic inner surface of the horseshoe. We infer that bulky BTX, bound at the level of the gating-hinge residues, prevents the S6 rearrangements that are necessary for closure of the activation gate. Our results reveal general similarities to, and differences from, BTX actions on eukaryotic Nav channels, whose major subunit is a single polypeptide formed by four concatenated, homologous, nonidentical domains that form a pseudosymmetric pore. Our determination of the mechanism by which BTX activates homotetrameric voltage-gated channels reveals further similarities between eukaryotic and prokaryotic Nav channels and emphasizes the tractability of bacterial Nav channels as models of voltage-dependent ion channel gating. The results contribute toward a deeper, atomic-level understanding of use-dependent natural and synthetic Nav channel agonists and antagonists, despite their overlapping binding motifs on the channel proteins.

scholarly journals Correction: Phosphorylation of a chronic pain mutation in the voltage-gated sodium channel Nav1.7 increases voltage sensitivity

2021 ◽  
Vol 297 (3) ◽  
pp. 101122
Author(s):  
Clara M. Kerth ◽  
Petra Hautvast ◽  
Jannis Körner ◽  
Angelika Lampert ◽  
Jannis E. Meents
Keyword(s):  
Chronic Pain ◽  
Sodium Channel ◽  
Voltage Sensitivity ◽  
Voltage Gated Sodium Channel ◽  
Voltage Gated

scholarly journals The Role of Voltage-Gated Sodium Channels in Pain Signaling

2019 ◽  
Vol 99 (2) ◽  
pp. 1079-1151 ◽  
Author(s):  
David L. Bennett ◽  
Alex J. Clark ◽  
Jianying Huang ◽  
Stephen G. Waxman ◽  
Sulayman D. Dib-Hajj
Keyword(s):  
Chronic Pain ◽  
Sodium Channels ◽  
Sensory Neuron ◽  
Sensory Neurons ◽  
Expression Patterns ◽  
Sensory Transduction ◽  
Gene Variants ◽  
Sensory Stimuli ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels

Acute pain signaling has a key protective role and is highly evolutionarily conserved. Chronic pain, however, is maladaptive, occurring as a consequence of injury and disease, and is associated with sensitization of the somatosensory nervous system. Primary sensory neurons are involved in both of these processes, and the recent advances in understanding sensory transduction and human genetics are the focus of this review. Voltage-gated sodium channels (VGSCs) are important determinants of sensory neuron excitability: they are essential for the initial transduction of sensory stimuli, the electrogenesis of the action potential, and neurotransmitter release from sensory neuron terminals. Nav1.1, Nav1.6, Nav1.7, Nav1.8, and Nav1.9 are all expressed by adult sensory neurons. The biophysical characteristics of these channels, as well as their unique expression patterns within subtypes of sensory neurons, define their functional role in pain signaling. Changes in the expression of VGSCs, as well as posttranslational modifications, contribute to the sensitization of sensory neurons in chronic pain states. Furthermore, gene variants in Nav1.7, Nav1.8, and Nav1.9 have now been linked to human Mendelian pain disorders and more recently to common pain disorders such as small-fiber neuropathy. Chronic pain affects one in five of the general population. Given the poor efficacy of current analgesics, the selective expression of particular VGSCs in sensory neurons makes these attractive targets for drug discovery. The increasing availability of gene sequencing, combined with structural modeling and electrophysiological analysis of gene variants, also provides the opportunity to better target existing therapies in a personalized manner.

scholarly journals Voltage gated sodium channels as therapeutic targets for chronic pain

2019 ◽  
Vol Volume 12 ◽  
pp. 2709-2722 ◽  
Author(s):  
Renee Siu Yu Ma ◽  
Kayani Kayani ◽  
Danniella Whyte Oshodi ◽  
Aiyesha Whyte Oshodi ◽  
Nitish Nachiappan ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Sodium Channels ◽  
Therapeutic Targets ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels

A Possible Explanation for a Neurotoxic Effect of the Anticancer Agent Oxaliplatin on Neuronal Voltage-Gated Sodium Channels

2001 ◽  
Vol 85 (5) ◽  
pp. 2293-2297 ◽  
Author(s):  
Françoise Grolleau ◽  
Laurence Gamelin ◽  
Michèle Boisdron-Celle ◽  
Bruno Lapied ◽  
Marcel Pelhate ◽  
...  
Keyword(s):  
Sodium Channels ◽  
Calcium Ions ◽  
Periplaneta Americana ◽  
Sodium Current ◽  
Current Amplitude ◽  
Patch Clamp Technique ◽  
Electrophysiological Properties ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels ◽  
Whole Cell Patch Clamp

Oxaliplatin, a new widely used anticancer drug, displays frequent, sometimes severe, acute sensory neurotoxicity accompanied by neuromuscular signs that look like the symptoms observed in tetany and myotonia. The whole cell patch-clamp technique was employed to investigate the oxaliplatin effects on the electrophysiological properties of short-term cultured dorsal unpaired median (DUM) neurons isolated from the CNS of the cockroach Periplaneta americana. Within the clinical concentration range, oxaliplatin (40–500 μM), applied intracellularly, decreased the amplitude of the voltage-gated sodium current resulting in a reduction of half the amplitude of the action potential. For comparison, two other platinum derivatives, cisplatin and carboplatin, were found to be ineffective at reducing the sodium current amplitude. In addition, we compared the oxaliplatin action to those of its metabolites dichloro-diaminocyclohexane platinum (dach-Cl2-platin) and oxalate. Oxalate (500 μM) was found to be effective, like oxaliplatin, at reducing the inward sodium current amplitude, whereas dach-Cl2-platin (500 μM) failed to change the current amplitude. Interestingly, the effect of oxalate or oxaliplatin could be mimicked by using intracellularly applied 10 mM bis-( o-aminophenoxy)- N,N,N′,N′-tetraacetic acid (BAPTA), known as chelator of calcium ions. We concluded that oxaliplatin was capable of altering the voltage-gated sodium channels through a pathway involving calcium ions probably immobilized by its metabolite oxalate. The medical interest of preventing acute neurotoxic side effects of oxaliplatin by infusing Ca2+ and Mg2+ is discussed.

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