Deletions in the Third Intracellular Loop of the Thyrotropin Receptor

Wonerow, Peter; Schöneberg, Torsten; Schultz, Günter; Gudermann, Thomas; Paschke, Ralf

doi:10.1074/jbc.273.14.7900

Cited by 76 publications

(66 citation statements)

References 43 publications

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“…Competitive binding studies were performed as previously described (Wonerow et al, 1998). To determine the TSH radioligand binding at a similar level of TSHR cell surface expression, we balanced the effect of SIAT 1 cotransfection on TSH receptor expression compared to empty pcDNA by cotransfecting the human V2 vasopressin receptor together with the TSH receptor and the SIAT 1 (Schoneberg et al, 1996;Neumann et al, 2001).…”

Section: Radioligand Binding Assaymentioning

confidence: 99%

Gene expression analysis reveals evidence for inactivation of the TGF-β signaling cascade in autonomously functioning thyroid nodules

et al. 2004

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Molecular eventsthat lead to the development of autonomously functioning thyroid nodules (AFTNs) are somatic mutations of the thyrotropin receptor (TSHR) in approximately 60% of the nodules and less frequently, somatic mutations in the G s a protein. However, AFTNs without known mutations indicate that other causes remain to be identified. Moreover, the impact of constitutively activating TSHR mutations on the signal transduction network of the thyroid epithelial cell is unknown. We therefore investigated gene expression in 15 AFTNs and their surrounding tissue using Affymetrix GeneChips. Most prominently, data analysis revealed a changed pattern of gene expression in the TGF-b signaling cascade and 25 differentially regulated genes in AFTNs, including thyroid peroxidase, type I iodothyronine deiodinase and sialyltransferase (SIAT) 1. Strikingly coexpression of SIAT 1 and TSHR in COS-7 cells increased TSH binding and cell surface expression of the TSHR. Moreover, differences in gene expression patterns for AFTNs with and without TSHR mutations indicate specific alterations of signal transduction in AFTNs without TSHR mutations. These results suggest that AFTNs with TSHR mutations harbor further mechanisms of forward stimulation. Furthermore, they give important leads to elucidate the molecular etiology of AFTNs without TSHR mutations.

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Section: Radioligand Binding Assaymentioning

confidence: 99%

Gene expression analysis reveals evidence for inactivation of the TGF-β signaling cascade in autonomously functioning thyroid nodules

et al. 2004

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“…The relative importance of distinct amino acids at codons 613 to 621 was clarified by deletion studies of several amino acids. Deletions at codons 619 and 613-617 resulted in ligand-independent receptor activation; however, deletions at codons 615 and 616 did not significantly affect the functional properties of the receptor [34]. These findings imply that the deletion or any change at codon 613, 614, or 617 may lead to constitutive activation of the receptor, despite nonconserved residues in the corresponding region of other G protein-coupled receptors [23,34].…”

Section: Discussionmentioning

confidence: 50%

“…All but one of these mutations [5,30,32,33]. The residues at codons 619 and 623 are highly conserved in the corresponding regions of other G protein-coupled receptors [23,34]. The relative importance of distinct amino acids at codons 613 to 621 was clarified by deletion studies of several amino acids.…”

Section: Discussionmentioning

confidence: 99%

“…Deletions at codons 619 and 613-617 resulted in ligand-independent receptor activation; however, deletions at codons 615 and 616 did not significantly affect the functional properties of the receptor [34]. These findings imply that the deletion or any change at codon 613, 614, or 617 may lead to constitutive activation of the receptor, despite nonconserved residues in the corresponding region of other G protein-coupled receptors [23,34]. In our study, the Asp617Tyr mutation resulted in constitutive activation of the cAMP pathway, which agreed with previous reports that most of mutations activated the cAMP pathway but not the inositol phosphate cascade ( Table 3).…”

Section: Discussionmentioning

confidence: 99%

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A Novel Thyrotropin Receptor Germline Mutation (Asp617Tyr) Causing Hereditary Hyperthyroidism

et al. 2007

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Abstract. Constitutively activating germline mutations of the thyrotropin receptor (TSHR) gene have been identified as a molecular cause of hereditary nonautoimmune hyperthyroidism. We describe here a Japanese kindred with two affected individuals who showed overt hyperthyroidism and mild goiter in the absence of TSHR antibodies. A novel heterozygous germline point mutation, identified in both individuals, resulted in an amino acid substitution of aspartic acid for tyrosine at codon 617 (Asp617Tyr) in the third intracellular loop of the TSHR. Screening of 7 additional family members led to the identification of the same mutation in 4 relatives: 1 had undergone thyroidectomy due to hyperthyroidism but 3 were asymptomatic with subclinical hyperthyroidism. In vitro functional studies of the Asp617Tyr TSHR demonstrated a constitutive activation of the cyclic adenosine monophosphate pathway, but not of the inositol phosphate cascade, with data similar to those of Asp619Gly, the first constitutively activating mutant TSHR identified. Treatment with inorganic iodine for 7 months successfully relieved all symptoms of hyperthyroidism in both patients.

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“…Forty eight hours after transfection, determination of cAMP accumulation was performed as previously described (30).…”

Section: Camp Accumulation Assaymentioning

confidence: 99%

Interactions between the extracellular domain and the extracellular loops as well as the 6th transmembrane domain are necessary for TSH receptor activation

Neumann

Claus²,

Paschke

2005

eur j endocrinol

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Objective: The molecular mechanisms of TSH receptor (TSHR) activation and intramolecular signal transduction are largely unknown. Deletion of the extracellular domain (ECD) of the TSHR results in increased constitutive activity, which suggests a self-inhibitory interaction between the ECD and the extracellular loops (ECLs) or the transmembrane domains (TMDs). To investigate these potential interactions and to pursue the idea that mutations in the ECD affect the constitutive activity of mutants in the ECLs or TMDs we generated double mutants between position 281 in the ECD and mutants in all three ECLs as well as the 6th TMD. Design: We combined mutation S281D, characterized by an impaired TSH-stimulated cAMP response, with the constitutively activating in vivo mutations I486F (1st ECL), I568T (2nd ECL), V656F (3rd ECL) and D633F (6th TMD). Further, we constructed double mutants containing the constitutively activating mutation S281N and one of the inactivating mutations D474E, T477I (1st ECL) and D633K (6th TMD). Results: The cAMP level of the double mutants with S281N and the inactive mutants in the 1st ECL was decreased below the level of the inactive single mutants, demonstrating that a constitutively activating mutation in the ECD cannot bypass disruption of signal transduction in the serpentine domain. In double mutants with S281D, basal and TSH-induced cAMP and inositol phosphate production of constitutively active mutants was reduced to the level of S281D. Conclusion: The dominance of S281D and the dependence of constitutively activating mutations in the ECLs on the functionally intact ECD strongly suggest that interactions between these receptor domains are required for TSHR activation and intramolecular signal transduction.European Journal of Endocrinology 152 625-634

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Deletions in the Third Intracellular Loop of the Thyrotropin Receptor

Cited by 76 publications

References 43 publications

Gene expression analysis reveals evidence for inactivation of the TGF-β signaling cascade in autonomously functioning thyroid nodules

Gene expression analysis reveals evidence for inactivation of the TGF-β signaling cascade in autonomously functioning thyroid nodules

A Novel Thyrotropin Receptor Germline Mutation (Asp617Tyr) Causing Hereditary Hyperthyroidism

Interactions between the extracellular domain and the extracellular loops as well as the 6th transmembrane domain are necessary for TSH receptor activation

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