Linked Life Data

16885209

Source:http://linkedlifedata.com/resource/pubmed/id/16885209

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2006-10-23
pubmed:abstractText
Mibefradil is a tetralol derivative once marketed to treat hyper-tension. Its primary target is the T-type Ca(2+) channel (IC(50), approximately 0.1-0.2 microM), but it also blocks Na(+),K(+),Cl(-), and other Ca(2+) channels at higher concentrations. We have recently reported state-dependent mibefradil block of Na(+) channels in which apparent affinity was enhanced when channels were recruited to slow-inactivated conformations. The structural determinants controlling mibefradil block have not been identified, although evidence suggests involvement of regions near or within the inner pore. We tested whether mibefradil interacts with the local anesthetic (LA) binding site, which includes residues in the S6 segments of domains (D) I, III, and IV. Mutagenesis of DIII S6 and DIVS6 did not reveal critical binding determinants. Substitution of Asn406 in DI S6 of cardiac Na(v)1.5, however, altered affinity in a manner dependent on the identity of the substituting residue. Replacing Asn406 with a phenylalanine or a cysteine increased affinity by 4- and 7-fold, respectively, thus conferring T-type Ca(2+) channel-like mibefradil sensitivity to the Na(+) channel. A series of other substitutions that varied in size, charge, and hydrophobicity had minimal effects on mibefradil block, but all mutations dramatically altered the magnitude and voltage-dependence of slow inactivation, consistent with data in other isoforms. Channels did not slow-inactivate, however, at the voltages used to assay mibefradil block, supporting the idea that Asn406 lies within or near the mibefradil binding site.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0026-895X
pubmed:author
pubmed:issnType
Print
pubmed:volume
70
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1514-23
pubmed:dateRevised
2011-7-22
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
An inner pore residue (Asn406) in the Nav1.5 channel controls slow inactivation and enhances mibefradil block to T-type Ca2+ channel levels.
pubmed:affiliation
Department of Medicine, University of Chicago, 5841 S. Maryland Ave, MC6094, IL 60637, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural