Linked Life Data

8663021

Source:http://linkedlifedata.com/resource/pubmed/id/8663021

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
25
pubmed:dateCreated
1996-8-13
pubmed:abstractText
The two known receptors mediating the actions of cholecystokinin (CCK) and gastrin, CCK type A (CCKAR) and CCK type B (CCKBR) receptors, are G protein-coupled receptors having approximately 50% amino acid homology. Both the CCKAR and CCKBR have high affinity for sulfated CCK peptides, while only the CCKBR has high affinity for gastrin peptides. To determine the structural basis for the selectivity of the CCKBR for gastrin, we first constructed a series of CCKB/AR chimeras in which restriction endonuclease-defined segments of the CCKBR were replaced with the corresponding segments of the CCKAR. Chimeras transiently expressed in COS-1 cells were screened for the selective loss of gastrin affinity according to the displacement of 125I-labeled Bolton-Hunter-CCK-8 binding by gastrin-17-I and CCK-8. The sequence spanning from transmembrane domain III (TM III) to TM V was the only segment that resulted in the selective loss of gastrin affinity. This segment could account for 100 of the expected 300-fold lower affinity of gastrin-17-I observed for the control CCKAR compared to the control CCKBR. Using site-directed mutagenesis in this segment of the CCKBR, we identified a sequence of 5 amino acids in the second extracellular loop responsible for this 100-fold selective loss in gastrin affinity. 125I-labeled Bolton-Hunter-CCK-8 binding displacement by L365,260 (a CCKBR selective antagonist) was unaffected by the changes in these 5 amino acids. These results present for the first time the identification of the amino acid sequence of the CCKBR conferring the majority of the selectivity for gastrin.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
271
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14698-706
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:8663021-Amino Acid Sequence, pubmed-meshheading:8663021-Animals, pubmed-meshheading:8663021-Benzodiazepinones, pubmed-meshheading:8663021-Binding, Competitive, pubmed-meshheading:8663021-Binding Sites, pubmed-meshheading:8663021-Cell Line, pubmed-meshheading:8663021-Cell Membrane, pubmed-meshheading:8663021-Cercopithecus aethiops, pubmed-meshheading:8663021-Gastrins, pubmed-meshheading:8663021-Humans, pubmed-meshheading:8663021-Indicators and Reagents, pubmed-meshheading:8663021-Kinetics, pubmed-meshheading:8663021-Models, Structural, pubmed-meshheading:8663021-Molecular Sequence Data, pubmed-meshheading:8663021-Mutagenesis, Site-Directed, pubmed-meshheading:8663021-Phenylurea Compounds, pubmed-meshheading:8663021-Point Mutation, pubmed-meshheading:8663021-Protein Structure, Secondary, pubmed-meshheading:8663021-Receptor, Cholecystokinin B, pubmed-meshheading:8663021-Receptors, Cholecystokinin, pubmed-meshheading:8663021-Recombinant Fusion Proteins, pubmed-meshheading:8663021-Sequence Homology, Amino Acid, pubmed-meshheading:8663021-Sincalide, pubmed-meshheading:8663021-Succinimides, pubmed-meshheading:8663021-Transfection
pubmed:year
1996
pubmed:articleTitle
A segment of five amino acids in the second extracellular loop of the cholecystokinin-B receptor is essential for selectivity of the peptide agonist gastrin.
pubmed:affiliation
Digestive Diseases Branch, NIDDK, National Institutes of Health, Bethesda, Maryland 20892-1804, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't