Linked Life Data

19703932

Source:http://linkedlifedata.com/resource/pubmed/id/19703932

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2009-12-1
pubmed:abstractText
Native GABA(A) channels display a single-channel conductance ranging between approximately 10 and 90 pS. Diazepam increases the conductance of some of these native channels but never those of recombinant receptors, unless they are coexpressed with GABARAP. This trafficking protein clusters recombinant receptors in the membrane, suggesting that high-conductance channels arise from receptors that are at locally high concentrations. The amphipathic (MA) helix that is present in the large cytoplasmic loop of every subunit of all ligand-gated ion channels mediates protein-protein interactions. Here we report that when applied to inside-out patches, a peptide mimicking the MA helix of the gamma2 subunit (gamma(381-403)) of the GABA(A) receptor abrogates the potentiating effect of diazepam on both endogenous receptors and recombinant GABA(A) receptors coexpressed with GABARAP, by substantially reducing their conductance. The protein interaction disrupted by the peptide did not involve GABARAP, because a shorter peptide (gamma(386-403)) known to compete with the gamma2-GABARAP interaction did not affect the conductance of recombinant alphabetagamma receptors coexpressed with GABARAP. The requirement for receptor clustering and the fact that the gamma2 MA helix is able to self-associate support a mechanism whereby adjacent GABA(A) receptors interact via their gamma2-subunit MA helices, altering ion permeation through each channel. Alteration of ion-channel function arising from dynamic interactions between ion channels of the same family has not been reported previously and highlights a novel way in which inhibitory neurotransmission in the brain may be differentially modulated.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1530-6860
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4361-9
pubmed:dateRevised
2011-3-3
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Protein interactions involving the gamma2 large cytoplasmic loop of GABA(A) receptors modulate conductance.
pubmed:affiliation
Structural Biology Programme, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't