Linked Life Data

10821684

Source:http://linkedlifedata.com/resource/pubmed/id/10821684

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
2000-6-21
pubmed:databankReference
pubmed:abstractText
The maxi-K channel from bovine aortic smooth muscle consists of a pore-forming alpha subunit and a regulatory beta1 subunit that modifies the biophysical and pharmacological properties of the alpha subunit. In the present study, we examine ChTX-S10A blocking kinetics of single maxi-K channels in planar lipid bilayers from smooth muscle or from tsA-201 cells transiently transfected with either alpha or alpha+beta 1 subunits. Under low external ionic strength conditions, maxi-K channels from smooth muscle showed ChTX-S10A block times, 48 +/- 12 s, that were similar to those expressing alpha+beta 1 subunits, 51 +/- 16 s. In contrast, with the alpha subunit alone, ChTX-S10A block times were much shorter, 5 +/- 0.6 s, and were qualitatively similar to previously reported values for the skeletal muscle maxi-K channel. Increasing the external ionic strength caused a decrease in ChTX-S10A block times for maxi-K channel complexes of alpha+beta 1 subunits but not of alpha subunits alone. These findings indicate that it may be possible to predict the association of beta 1 subunits with native maxi-K channels by monitoring the kinetics of ChTX blockade of single channels, and they suggest that maxi-K channels in skeletal muscle do not contain a beta 1 subunit like the one present in smooth muscle. To further test this hypothesis, we examined the binding and cross-linking properties of [(125)I]-IbTX-D19Y/Y36F to both bovine smooth muscle and rabbit skeletal muscle membranes. [(125)I]-IbTX-D19Y/Y36F binds to rabbit skeletal muscle membranes with the same affinity as it does to smooth muscle membranes. However, specific cross-linking of [(125)I]-IbTX-D19Y/Y36F was observed into the beta 1 subunit of smooth muscle but not in skeletal muscle. Taken together, these data suggest that studies of ChTX block of single maxi-K channels provide an approach for characterizing structural and functional features of the alpha/beta 1 interaction.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6115-22
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:10821684-Animals, pubmed-meshheading:10821684-Aorta, pubmed-meshheading:10821684-Cattle, pubmed-meshheading:10821684-Charybdotoxin, pubmed-meshheading:10821684-Cross-Linking Reagents, pubmed-meshheading:10821684-Humans, pubmed-meshheading:10821684-Kinetics, pubmed-meshheading:10821684-Large-Conductance Calcium-Activated Potassium Channel..., pubmed-meshheading:10821684-Large-Conductance Calcium-Activated Potassium Channels, pubmed-meshheading:10821684-Lipid Bilayers, pubmed-meshheading:10821684-Molecular Sequence Data, pubmed-meshheading:10821684-Muscle, Skeletal, pubmed-meshheading:10821684-Muscle, Smooth, Vascular, pubmed-meshheading:10821684-Organ Specificity, pubmed-meshheading:10821684-Peptides, pubmed-meshheading:10821684-Potassium Channel Blockers, pubmed-meshheading:10821684-Potassium Channels, pubmed-meshheading:10821684-Potassium Channels, Calcium-Activated, pubmed-meshheading:10821684-Protein Binding, pubmed-meshheading:10821684-Rabbits, pubmed-meshheading:10821684-Static Electricity
pubmed:year
2000
pubmed:articleTitle
Interaction of charybdotoxin S10A with single maxi-K channels: kinetics of blockade depend on the presence of the beta 1 subunit.
pubmed:affiliation
Department of Biochemistry, Temple University School of Medicine, 3420 North Broad Street, Philadelphia, Pennsylvania 19140, USA. giang@unix.temple.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.