Linked Life Data

20921230

Source:http://linkedlifedata.com/resource/pubmed/id/20921230

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
48
pubmed:dateCreated
2010-11-24
pubmed:abstractText
Many ion channels are modulated by phosphatidylinositol 4,5-bisphosphate (PIP(2)), but studies examining the PIP(2) dependence of channel activity have been limited to cell expression systems, which present difficulties for controlling membrane composition. We have characterized the PIP(2) dependence of purified human Kir2.1 and Kir2.2 activity using (86)Rb(+) flux and patch clamp assays in liposomes of defined composition. We definitively show that these channels are directly activated by PIP(2) and that PIP(2) is absolutely required in the membrane for channel activity. The results provide the first quantitative description of the dependence of eukaryotic Kir channel function on PIP(2) levels in the membrane; Kir2.1 shows measureable activity in as little as 0.01% PIP(2), and open probability increases to ?0.4 at 1% PIP(2). Activation of Kir2.1 by phosphatidylinositol phosphates is also highly selective for PIP(2); PI, PI(4)P, and PI(5)P do not activate channels, and PI(3,4,5)P(3) causes minimal activity. The PIP(2) dependence of eukaryotic Kir activity is almost exactly opposite that of KirBac1.1, which shows marked inhibition by PIP(2). This raises the interesting hypothesis that PIP(2) activation of eukaryotic channels reflects an evolutionary adaptation of the channel to the appearance of PIP(2) in the eukaryotic cell membrane.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
26
pubmed:volume
285
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
37129-32
pubmed:dateRevised
2011-1-6
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Direct and specific activation of human inward rectifier K+ channels by membrane phosphatidylinositol 4,5-bisphosphate.
pubmed:affiliation
Department of Cell Biology and Physiology and the Center for Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St Louis, Missouri 63110, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural