Linked Life Data

9786876

Source:http://linkedlifedata.com/resource/pubmed/id/9786876

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
44
pubmed:dateCreated
1998-12-1
pubmed:abstractText
The enteroendocrine hormone, gastrin, exerts trophic effects on the gastric mucosa through the CCK-B/gastrin receptor (CCK-BR). To varying degrees in different species, excess circulating gastrin leads to proliferation of enterochromaffin-like cells and to the development of gastric carcinoid tumors. The African rodent, Mastomys natalensis, is distinguished from other mammals by its propensity toward CCK-BR-mediated growth even in the absence of hypergastrinemia. Here, we report that the Mastomys CCK-BR, when expressed in COS-7 cells, differs from the respective human, canine, and rat receptor homologs by its ability to trigger ligand-independent (i.e., constitutive) inositol phosphate formation. To define the molecular basis of this observation, a series of Mastomys-human chimeric receptors was investigated. Functional characterization of these constructs revealed that a limited segment of the Mastomys CCK-BR, transmembrane domain VI through the C-terminal end, is sufficient to confer constitutive activity to the human protein. Mutagenesis studies within this CCK-BR region defined a combination of three Mastomys amino acids that, when introduced into the human receptor, together conferred a level of ligand-independent signaling comparable with the Mastomys CCK-BR. Complementing prior observations that single point mutations can lead to ligand-independent signaling, our findings suggest that multiple naturally occurring amino acid polymorphisms and/or mutations may together result in an enhanced basal level of receptor activity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
273
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
28779-84
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Interspecies polymorphisms confer constitutive activity to the Mastomys cholecystokinin-B/gastrin receptor.
pubmed:affiliation
Division of Gastroenterology and GRASP Digestive Disease Center, Tupper Research Institute, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't