Linked Life Data

11973330

Source:http://linkedlifedata.com/resource/pubmed/id/11973330

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
27
pubmed:dateCreated
2002-7-1
pubmed:abstractText
The large size (six membrane-spanning repeats in each of four domains) and asymmetric architecture of the voltage-dependent Na+ channel has hindered determination of its structure. With the goal of determining the minimum structure of the Na+ channel permeation pathway, we created two stable cell lines expressing the voltage-dependent rat skeletal muscle Na+ channel (micro1) with a polyhistidine tag on the C terminus (muHis) and pore-only micro1 (muPore) channels with S1-S4 in all domains removed. Both constructs were recognized by a Na+ channel-specific antibody on a Western blot. muHis channels exhibited the same functional properties as wild-type micro1. In contrast, muPore channels did not conduct Na+ currents nor did they bind [3H]saxitoxin. Veratridine caused 40 and 54% cell death in muHis- and muPore-expressing cells, respectively. However, veratridine-induced cell death could only be blocked by tetrodotoxin in cells expressing muHis, but not muPore. Furthermore, using a fluorescent Na+ indicator, we measured changes in intracellular Na+ induced by veratridine and a brevotoxin analogue, pumiliotoxin. When calibrated to the maximum signal after addition of gramicidin, the maximal percent increases in fluorescence (deltaF) were 35 and 31% in cells expressing muHis and muPore, respectively. Moreover, in the presence of 1 microm tetrodotoxin, deltaF decreased significantly to 10% in muHis- but not in muPore-expressing cells (43%). In conclusion, S5-P-S6 segments of micro1 channels form a toxin-activable ionophore but do not reconstitute the Na+ channel permeation pathway with full fidelity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
277
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
24653-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
A "minimal" sodium channel construct consisting of ligated S5-P-S6 segments forms a toxin-activatable ionophore.
pubmed:affiliation
Institute of Molecular Cardiobiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't