| Structural highlights
Disease
SCN9A_HUMAN Channelopathy-associated congenital insensitivity to pain;Dravet syndrome;Primary erythromelalgia;Sodium channelopathy-related small fiber neuropathy;Generalized epilepsy with febrile seizures-plus;Hereditary sensory and autonomic neuropathy type 2;Paroxysmal extreme pain disorder;Erythromelalgia. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry. The disease is caused by mutations affecting the gene represented in this entry.
Function
SCN9A_HUMAN Mediates the voltage-dependent sodium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a sodium-selective channel through which Na(+) ions may pass in accordance with their electrochemical gradient (PubMed:7720699, PubMed:17167479, PubMed:25240195, PubMed:26680203, PubMed:15385606, PubMed:16988069, PubMed:17145499, PubMed:19369487, PubMed:24311784). It is a tetrodotoxin-sensitive Na(+) channel isoform (PubMed:7720699). Plays a role in pain mechanisms, especially in the development of inflammatory pain (PubMed:17167479, PubMed:17145499, PubMed:19369487, PubMed:24311784).[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] A8EVM5_ALIB4
Publication Abstract from PubMed
Voltage-gated sodium (Nav) channels are targets of disease mutations, toxins, and therapeutic drugs. Despite recent advances, the structural basis of voltage sensing, electromechanical coupling, and toxin modulation remains ill-defined. Protoxin-II (ProTx2) from the Peruvian green velvet tarantula is an inhibitor cystine-knot peptide and selective antagonist of the human Nav1.7 channel. Here, we visualize ProTx2 in complex with voltage-sensor domain II (VSD2) from Nav1.7 using X-ray crystallography and cryoelectron microscopy. Membrane partitioning orients ProTx2 for unfettered access to VSD2, where ProTx2 interrogates distinct features of the Nav1.7 receptor site. ProTx2 positions two basic residues into the extracellular vestibule to antagonize S4 gating-charge movement through an electrostatic mechanism. ProTx2 has trapped activated and deactivated states of VSD2, revealing a remarkable approximately 10 A translation of the S4 helix, providing a structural framework for activation gating in voltage-gated ion channels. Finally, our results deliver key templates to design selective Nav channel antagonists.
Structural Basis of Nav1.7 Inhibition by a Gating-Modifier Spider Toxin.,Xu H, Li T, Rohou A, Arthur CP, Tzakoniati F, Wong E, Estevez A, Kugel C, Franke Y, Chen J, Ciferri C, Hackos DH, Koth CM, Payandeh J Cell. 2019 Feb 7;176(4):702-715.e14. doi: 10.1016/j.cell.2018.12.018. Epub 2019, Jan 17. PMID:30661758[11]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Jo T, Nagata T, Iida H, Imuta H, Iwasawa K, Ma J, Hara K, Omata M, Nagai R, Takizawa H, Nagase T, Nakajima T. Voltage-gated sodium channel expressed in cultured human smooth muscle cells: involvement of SCN9A. FEBS Lett. 2004 Jun 4;567(2-3):339-43. PMID:15178348 doi:http://dx.doi.org/10.1016/j.febslet.2004.04.092
- ↑ Cummins TR, Dib-Hajj SD, Waxman SG. Electrophysiological properties of mutant Nav1.7 sodium channels in a painful inherited neuropathy. J Neurosci. 2004 Sep 22;24(38):8232-6. PMID:15385606 doi:http://dx.doi.org/10.1523/JNEUROSCI.2695-04.2004
- ↑ Choi JS, Dib-Hajj SD, Waxman SG. Inherited erythermalgia: limb pain from an S4 charge-neutral Na channelopathy. Neurology. 2006 Nov 14;67(9):1563-7. doi: 10.1212/01.wnl.0000231514.33603.1e., Epub 2006 Sep 20. PMID:16988069 doi:http://dx.doi.org/10.1212/01.wnl.0000231514.33603.1e
- ↑ Fertleman CR, Baker MD, Parker KA, Moffatt S, Elmslie FV, Abrahamsen B, Ostman J, Klugbauer N, Wood JN, Gardiner RM, Rees M. SCN9A mutations in paroxysmal extreme pain disorder: allelic variants underlie distinct channel defects and phenotypes. Neuron. 2006 Dec 7;52(5):767-74. doi: 10.1016/j.neuron.2006.10.006. PMID:17145499 doi:http://dx.doi.org/10.1016/j.neuron.2006.10.006
- ↑ Cox JJ, Reimann F, Nicholas AK, Thornton G, Roberts E, Springell K, Karbani G, Jafri H, Mannan J, Raashid Y, Al-Gazali L, Hamamy H, Valente EM, Gorman S, Williams R, McHale DP, Wood JN, Gribble FM, Woods CG. An SCN9A channelopathy causes congenital inability to experience pain. Nature. 2006 Dec 14;444(7121):894-8. PMID:17167479 doi:http://dx.doi.org/nature05413
- ↑ Han C, Dib-Hajj SD, Lin Z, Li Y, Eastman EM, Tyrrell L, Cao X, Yang Y, Waxman SG. Early- and late-onset inherited erythromelalgia: genotype-phenotype correlation. Brain. 2009 Jul;132(Pt 7):1711-22. doi: 10.1093/brain/awp078. Epub 2009 Apr 15. PMID:19369487 doi:http://dx.doi.org/10.1093/brain/awp078
- ↑ Eberhardt M, Nakajima J, Klinger AB, Neacsu C, Huhne K, O'Reilly AO, Kist AM, Lampe AK, Fischer K, Gibson J, Nau C, Winterpacht A, Lampert A. Inherited pain: sodium channel Nav1.7 A1632T mutation causes erythromelalgia due to a shift of fast inactivation. J Biol Chem. 2014 Jan 24;289(4):1971-80. doi: 10.1074/jbc.M113.502211. Epub 2013 , Dec 5. PMID:24311784 doi:http://dx.doi.org/10.1074/jbc.M113.502211
- ↑ Tan ZY, Priest BT, Krajewski JL, Knopp KL, Nisenbaum ES, Cummins TR. Protein kinase C enhances human sodium channel hNav1.7 resurgent currents via a serine residue in the domain III-IV linker. FEBS Lett. 2014 Nov 3;588(21):3964-9. doi: 10.1016/j.febslet.2014.09.011. Epub, 2014 Sep 19. PMID:25240195 doi:http://dx.doi.org/10.1016/j.febslet.2014.09.011
- ↑ Ahuja S, Mukund S, Deng L, Khakh K, Chang E, Ho H, Shriver S, Young C, Lin S, Johnson JP Jr, Wu P, Li J, Coons M, Tam C, Brillantes B, Sampang H, Mortara K, Bowman KK, Clark KR, Estevez A, Xie Z, Verschoof H, Grimwood M, Dehnhardt C, Andrez JC, Focken T, Sutherlin DP, Safina BS, Starovasnik MA, Ortwine DF, Franke Y, Cohen CJ, Hackos DH, Koth CM, Payandeh J. Structural basis of Nav1.7 inhibition by an isoform-selective small-molecule antagonist. Science. 2015 Dec 18;350(6267):aac5464. doi: 10.1126/science.aac5464. PMID:26680203 doi:http://dx.doi.org/10.1126/science.aac5464
- ↑ Klugbauer N, Lacinova L, Flockerzi V, Hofmann F. Structure and functional expression of a new member of the tetrodotoxin-sensitive voltage-activated sodium channel family from human neuroendocrine cells. EMBO J. 1995 Mar 15;14(6):1084-90. PMID:7720699
- ↑ Xu H, Li T, Rohou A, Arthur CP, Tzakoniati F, Wong E, Estevez A, Kugel C, Franke Y, Chen J, Ciferri C, Hackos DH, Koth CM, Payandeh J. Structural Basis of Nav1.7 Inhibition by a Gating-Modifier Spider Toxin. Cell. 2019 Feb 7;176(4):702-715.e14. doi: 10.1016/j.cell.2018.12.018. Epub 2019, Jan 17. PMID:30661758 doi:http://dx.doi.org/10.1016/j.cell.2018.12.018
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