Linked Life Data

12107237

Source:http://linkedlifedata.com/resource/pubmed/id/12107237

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2002-7-10
pubmed:abstractText
Most of the TSH effects on the proliferation and differentiation of thyroid cells are mediated by cAMP via an adenylyl cyclase-activating Gs protein. TSH receptor responsiveness in cell cultures, is regulated by G protein-coupled receptor kinase (GRK) 2 and 5. To determine whether an alteration in activity and expression of GRKs might be associated with variable levels of TSH receptor desensitization in vivo, we studied human thyroid tissues including 21 normal tissues and 18 differentiated carcinomas. GRK activity was assayed by rhodopsin phosphorylation, and GRK protein and mRNA expressions assessed by immunoblotting and real-time quantitative RT-PCR, respectively. GRK2 and GRK5 were found as the predominant isoforms in the human thyroid. GRK5 protein expression was significantly decreased in differentiated thyroid carcinoma (P < 0.02) and paralleled a decrease in GRK mRNA expression (P < 0.02). In contrast, no difference in protein and mRNA levels of GRK2 were observed between normal and cancerous thyroid tissues. Although GRK2 protein levels correlated with GRK activities, we demonstrated a significant increase in GRK activity in differentiated thyroid carcinoma (P < 0.02). Less TSH receptor desensitization occurred in differentiated carcinoma than in normal thyroid tissue, as judged by TSH-stimulated cAMP response in human thyroid cells in primary culture. In conclusion, this study indicates that GRK2 activity and GRK5 expression have opposite regulations in cancer cells. Furthermore, the decrease in GRK5 expression may underlie the reduction in homologous desensitization of the TSH receptor in differentiated thyroid carcinoma, contributing to explain the increased cAMP levels in these tumors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0021-972X
pubmed:author
pubmed:issnType
Print
pubmed:volume
87
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3279-86
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:12107237-Adenocarcinoma, Follicular, pubmed-meshheading:12107237-Adult, pubmed-meshheading:12107237-Aged, pubmed-meshheading:12107237-Carcinoma, pubmed-meshheading:12107237-Carcinoma, Papillary, pubmed-meshheading:12107237-Cyclic AMP-Dependent Protein Kinases, pubmed-meshheading:12107237-Female, pubmed-meshheading:12107237-G-Protein-Coupled Receptor Kinase 2, pubmed-meshheading:12107237-G-Protein-Coupled Receptor Kinase 3, pubmed-meshheading:12107237-Humans, pubmed-meshheading:12107237-Male, pubmed-meshheading:12107237-Middle Aged, pubmed-meshheading:12107237-Protein-Serine-Threonine Kinases, pubmed-meshheading:12107237-RNA, Messenger, pubmed-meshheading:12107237-Receptors, Thyrotropin, pubmed-meshheading:12107237-Reference Values, pubmed-meshheading:12107237-Thyroid Gland, pubmed-meshheading:12107237-Thyroid Neoplasms, pubmed-meshheading:12107237-beta-Adrenergic Receptor Kinases
pubmed:year
2002
pubmed:articleTitle
Expression and activity of g protein-coupled receptor kinases in differentiated thyroid carcinoma.
pubmed:affiliation
Biophysics Laboratory, Department of Pathology, Jean Bernard Hospital, BP 577, 86021 Poitiers Cedex, France. t.metaye@chu-poitiers.fr
pubmed:publicationType
Journal Article