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Article: Molecular motions of the outer ring of charge of the sodium channel: Do they couple to slow inactivation?

TitleMolecular motions of the outer ring of charge of the sodium channel: Do they couple to slow inactivation?
Authors
KeywordsCysteine mutagenesis
Disulfide bond
Electrophysiology
rNav1.4 channel
Issue Date2003
PublisherRockefeller University Press. The Journal's web site is located at www.jgp.org/
Citation
Journal Of General Physiology, 2003, v. 122 n. 3, p. 323-332 How to Cite?
AbstractIn contrast to fast inactivation, the molecular basis of sodium (Na) channel slow inactivation is poorly understood. It has been suggested that structural rearrangements in the outer pore mediate slow inactivation of Na channels similar to C-type inactivation in potassium (K) channels. We probed the role of the outer ring of charge in inactivation gating by paired cysteine mutagenesis in the rat skeletal muscle Na channel (rNav1.4). The outer charged ring residues were substituted with cysteine, paired with cysteine mutants at other positions in the external pore, and coexpressed with rat brain β 1 in Xenopus oocytes. Dithiolthreitol (DTT) markedly increased the current in E403C+E758C double mutant, indicating the spontaneous formation of a disulfide bond and proximity of the α carbons of these residues of no more than 7 Å. The redox catalyst Cu(II) (1,10-phenanthroline) 3 (Cu(phe) 3) reduced the peak current of double mutants (E403C+E758C, E403C+D1241C, E403C+D1532C, and D1241C+D1532C) at a rate proportional to the stimulation frequency. Voltage protocols that favored occupancy of slow inactivation states completely prevented Cu(phe) 3 modification of outer charged ring paired mutants E403C+E758C, E403C+D1241C, and E403C+D1532C. In contrast, voltage protocols that favored slow inactivation did not prevent Cu(phe) 3 modification of other double mutants such as E403C+W756C, E403C+W1239C, and E403C+W1531C. Our data suggest that slow inactivation of the Na channel is associated with a structural rearrangement of the outer ring of charge.
Persistent Identifierhttp://hdl.handle.net/10722/91680
ISSN
2015 Impact Factor: 4.511
2015 SCImago Journal Rankings: 3.061
PubMed Central ID
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorXiong, Wen_HK
dc.contributor.authorLi, RAen_HK
dc.contributor.authorTian, Yen_HK
dc.contributor.authorTomaselli, GFen_HK
dc.date.accessioned2010-09-17T10:23:14Z-
dc.date.available2010-09-17T10:23:14Z-
dc.date.issued2003en_HK
dc.identifier.citationJournal Of General Physiology, 2003, v. 122 n. 3, p. 323-332en_HK
dc.identifier.issn0022-1295en_HK
dc.identifier.urihttp://hdl.handle.net/10722/91680-
dc.description.abstractIn contrast to fast inactivation, the molecular basis of sodium (Na) channel slow inactivation is poorly understood. It has been suggested that structural rearrangements in the outer pore mediate slow inactivation of Na channels similar to C-type inactivation in potassium (K) channels. We probed the role of the outer ring of charge in inactivation gating by paired cysteine mutagenesis in the rat skeletal muscle Na channel (rNav1.4). The outer charged ring residues were substituted with cysteine, paired with cysteine mutants at other positions in the external pore, and coexpressed with rat brain β 1 in Xenopus oocytes. Dithiolthreitol (DTT) markedly increased the current in E403C+E758C double mutant, indicating the spontaneous formation of a disulfide bond and proximity of the α carbons of these residues of no more than 7 Å. The redox catalyst Cu(II) (1,10-phenanthroline) 3 (Cu(phe) 3) reduced the peak current of double mutants (E403C+E758C, E403C+D1241C, E403C+D1532C, and D1241C+D1532C) at a rate proportional to the stimulation frequency. Voltage protocols that favored occupancy of slow inactivation states completely prevented Cu(phe) 3 modification of outer charged ring paired mutants E403C+E758C, E403C+D1241C, and E403C+D1532C. In contrast, voltage protocols that favored slow inactivation did not prevent Cu(phe) 3 modification of other double mutants such as E403C+W756C, E403C+W1239C, and E403C+W1531C. Our data suggest that slow inactivation of the Na channel is associated with a structural rearrangement of the outer ring of charge.en_HK
dc.languageengen_HK
dc.publisherRockefeller University Press. The Journal's web site is located at www.jgp.org/en_HK
dc.relation.ispartofJournal of General Physiologyen_HK
dc.subjectCysteine mutagenesisen_HK
dc.subjectDisulfide bonden_HK
dc.subjectElectrophysiologyen_HK
dc.subjectrNav1.4 channelen_HK
dc.titleMolecular motions of the outer ring of charge of the sodium channel: Do they couple to slow inactivation?en_HK
dc.typeArticleen_HK
dc.identifier.emailLi, RA:ronaldli@hkucc.hku.hken_HK
dc.identifier.authorityLi, RA=rp01352en_HK
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.1085/jgp.200308881en_HK
dc.identifier.pmid12913092-
dc.identifier.pmcidPMC2234489-
dc.identifier.scopuseid_2-s2.0-0141513676en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0141513676&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume122en_HK
dc.identifier.issue3en_HK
dc.identifier.spage323en_HK
dc.identifier.epage332en_HK
dc.identifier.isiWOS:000185299100008-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridXiong, W=8670689200en_HK
dc.identifier.scopusauthoridLi, RA=7404724466en_HK
dc.identifier.scopusauthoridTian, Y=10340915900en_HK
dc.identifier.scopusauthoridTomaselli, GF=7005223451en_HK

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