Linked Life Data

9837919

Source:http://linkedlifedata.com/resource/pubmed/id/9837919

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
50
pubmed:dateCreated
1999-1-14
pubmed:abstractText
The amino-terminal ectodomain of thyrotropin (TSH) receptor (TSHR) is heavily glycosylated with asparagine-linked (N-linked) oligosaccharides. The present studies were designed to evaluate how acquisition and processing of N-linked oligosaccharides play a role in the functional maturation of human TSHR. A glycosylation inhibitor tunicamycin, which inhibits the first step of N-linked glycosylation (acquisition of N-linked oligosaccharides), and a series of mutant Chinese hamster ovary (CHO)-Lec cells defective in the different steps of glycosylation processing were used. Inhibition of acquisition of N-linked oligosaccharides by tunicamycin treatment in CHO cells stably expressing TSHR produced nonglycosylated TSHR, which was totally nonfunctional. In contrast, all of the TSHRs synthesized in mutant CHO-Lec1, 2, and 8 cells (mannose-rich, sialic acid-deficient, and galactose-deficient oligosaccharides, respectively) bound TSH and produced cAMP in response to TSH with an affinity and an EC50 similar to those in TSHR expressed in parental CHO cells (CHO-TSHR; sialylated oligosaccharides). However, Lec1-TSHR and Lec2-TSHR were not efficiently expressed on the cell surface, whereas the expression levels of Lec8-TSHR and CHO-TSHR were essentially identical. All of the TSHRs expressed in CHO-Lec cells cleaved into two subunits. Finally, anti-TSHR autoantibodies from Graves' patients interacted with all of the TSHRs harboring different oligosaccharides to a similar extent. These data demonstrate that acquisition and processing of N-linked oligosaccharides of TSHR appear to be essential for correct folding in the endoplasmic reticulum and for cell surface targeting in the Golgi apparatus. We also show that complex type carbohydrates are not crucially involved in the interaction of TSHR with TSH and anti-TSHR autoantibodies.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
273
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
33423-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:9837919-Animals, pubmed-meshheading:9837919-Asparagine, pubmed-meshheading:9837919-Autoantibodies, pubmed-meshheading:9837919-Blotting, Western, pubmed-meshheading:9837919-CHO Cells, pubmed-meshheading:9837919-Carbohydrate Sequence, pubmed-meshheading:9837919-Cell Membrane, pubmed-meshheading:9837919-Clone Cells, pubmed-meshheading:9837919-Cricetinae, pubmed-meshheading:9837919-Cyclic AMP, pubmed-meshheading:9837919-Humans, pubmed-meshheading:9837919-Molecular Sequence Data, pubmed-meshheading:9837919-Oligosaccharides, pubmed-meshheading:9837919-Precipitin Tests, pubmed-meshheading:9837919-Protein Binding, pubmed-meshheading:9837919-Protein Folding, pubmed-meshheading:9837919-Receptors, Thyrotropin, pubmed-meshheading:9837919-Thyrotropin, pubmed-meshheading:9837919-Tunicamycin
pubmed:year
1998
pubmed:articleTitle
Role of asparagine-linked oligosaccharides in protein folding, membrane targeting, and thyrotropin and autoantibody binding of the human thyrotropin receptor.
pubmed:affiliation
Department of Pharmacology 1, Nagasaki University School of Medicine, Nagasaki, 852-8523, Japan. nagayama@net.nagasaki-u.ac.jp
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't