Linked Life Data

2000135

Source:http://linkedlifedata.com/resource/pubmed/id/2000135

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6310
pubmed:dateCreated
1991-4-9
pubmed:abstractText
The sodium-calcium exchanger is critical in the normal functioning of many cells. In heart muscle, it is the principal way by which the cells keep the concentration of intracellular calcium low, pumping out the Ca2+ that enters the cytosol through L-type Ca2+ channels. The exchanger may also contribute to the triggering of Ca2+ release during voltage-activated excitation-contraction coupling in heart. Time resolved examination of the conformational changes of macromolecules in living cells has so far been largely restricted to ion-channel proteins whose gating is voltage-dependent. We have now directly measured electrical currents arising from the molecular rearrangements of the sarcolemmal Na-Ca exchanger. Changes in the conformation of the exchanger protein were activated by a rapid increase in the intracellular calcium concentration produced by flash photolysis of caged calcium in voltage-clamped heart cells. Two components of membrane current were produced, reflecting a calcium-dependent conformational change of the transporter proteins and net transport of ions by the exchanger. The properties of these components provide evidence that the Na-Ca exchanger protein undergoes two consecutive membrane-crossing molecular transitions that each move charge, and that there are at least 250 exchangers per micron 2 turning over up to 2,500 times per second.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0028-0836
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
349
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
621-4
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Molecular operations of the sodium-calcium exchanger revealed by conformation currents.
pubmed:affiliation
Department of Physiology, University of Maryland School of Medicine, Baltimore 21201.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't