Linked Life Data

18247581

Source:http://linkedlifedata.com/resource/pubmed/id/18247581

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2008-3-3
pubmed:abstractText
G protein-coupled receptor (GPCR) function can be modulated by different classes of ligands including full and inverse agonists. At present, little is known about the conformational changes that agonist ligands induce in their target GPCRs. In this study, we employed an in situ disulfide cross-linking strategy to monitor ligand-induced structural changes in a series of cysteine (Cys)-substituted mutant M 3 muscarinic acetylcholine receptors. One of our goals was to study whether the cytoplasmic end of transmembrane domain V (TM V), a region known to be critically involved in receptor/G protein coupling, undergoes a major conformational change, similar to the adjacent region of TM VI. Another goal was to determine and compare the disulfide cross-linking patterns observed after treatment of the different mutant receptors with full versus inverse muscarinic agonists. Specifically, we generated 20 double Cys mutant M 3 receptors harboring one Cys substitution within the cytoplasmic end of TM V (L249-I253) and a second one within the cytoplasmic end of TM VI (A489-L492). These receptors were transiently expressed in COS-7 cells and subsequently characterized in pharmacological and disulfide cross-linking studies. Our cross-linking data, in conjunction with a three-dimensional model of the M 3 muscarinic receptor, indicate that M 3 receptor activation does not trigger major structural disturbances within the cytoplasmic segment of TM V, in contrast to the pronounced structural changes predicted to occur at the cytoplasmic end of TM VI. We also demonstrated that full and inverse muscarinic agonists had distinct effects on the efficiency of disulfide bond formation in specific double Cys mutant M 3 receptors. The present study provides novel information about the dynamic changes that accompany M 3 receptor activation and how the receptor conformations induced (or stabilized) by full versus inverse muscarinic agonists differ from each other at the molecular level. Because all class I GPCRs are predicted to share a similar transmembrane topology, the conclusions drawn from the present study should be of broad general relevance.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2776-88
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Ligand-specific changes in M3 muscarinic acetylcholine receptor structure detected by a disulfide scanning strategy.
pubmed:affiliation
Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), 8 Center Drive, Bethesda, Maryland 20892-0810, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Intramural