Linked Life Data

20639197

Source:http://linkedlifedata.com/resource/pubmed/id/20639197

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
41
pubmed:dateCreated
2010-10-4
pubmed:abstractText
?-aminobutyric acid type A (GABA(A)) receptors are heteropentameric glycoproteins. Based on consensus sequences, the GABA(A) receptor ?2 subunit contains three potential N-linked glycosylation sites, Asn-32, Asn-104, and Asn-173. Homology modeling indicates that Asn-32 and Asn-104 are located before the ?1 helix and in loop L3, respectively, near the top of the subunit-subunit interface on the minus side, and that Asn-173 is located in the Cys-loop near the bottom of the subunit N-terminal domain. Using site-directed mutagenesis, we demonstrated that all predicted ?2 subunit glycosylation sites were glycosylated in transfected HEK293T cells. Glycosylation of each site, however, produced specific changes in ?1?2 receptor surface expression and function. Although glycosylation of Asn-173 in the Cys-loop was important for stability of ?2 subunits when expressed alone, results obtained with flow cytometry, brefeldin A treatment, and endo-?-N-acetylglucosaminidase H digestion suggested that glycosylation of Asn-104 was required for efficient ?1?2 receptor assembly and/or stability in the endoplasmic reticulum. Patch clamp recording revealed that mutation of each site to prevent glycosylation decreased peak ?1?2 receptor current amplitudes and altered the gating properties of ?1?2 receptor channels by reducing mean open time due to a reduction in the proportion of long open states. In addition to functional heterogeneity, endo-?-N-acetylglucosaminidase H digestion and glycomic profiling revealed that surface ?2 subunit N-glycans at Asn-173 were high mannose forms that were different from those of Asn-32 and N104. Using a homology model of the pentameric extracellular domain of ?1?2 channel, we propose mechanisms for regulation of GABA(A) receptors by glycosylation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
8
pubmed:volume
285
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
31348-61
pubmed:dateRevised
2011-10-10
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Glycosylation of {beta}2 subunits regulates GABAA receptor biogenesis and channel gating.
pubmed:affiliation
Department of Neurology, Vanderbilt University, Nashville, Tennessee 37232, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural