The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Gerd Krause - One of the best experts on this subject based on the ideXlab platform.
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Differences in Signal Activation by LH and hCG are Mediated by the LH/CG Receptor’s Extracellular Hinge Region
Frontiers in Endocrinology, 2015Co-Authors: Paul Grzesik, Annika Kreuchwig, Claudia Rutz, Jens Furkert, Burkhard Wiesner, Ralf Schuelein, Gunnar Kleinau, Joerg Gromoll, Gerd KrauseAbstract:The human lutropin/choriogonadotropin receptor (LHCGR) can be activated by binding two slightly different gonadotropic glycoprotein hormones, choriogonadotropin (CG) - secreted by the placenta, and lutropin (LH) - produced by the pituitary. They induce different signaling profiles at the LHCGR. This cannot be explained by binding to the receptor's leucine-rich repeat domain (LRRD), as this binding is similar for the two hormones. We therefore speculate that there are previously unknown differences in the hormone/receptor interaction at the extracellular Hinge Region, which might help to understand functional differences between the two hormones. We have therefore performed a detailed study of the binding and action of LH and CG at the LHCGR Hinge Region. We focused on a primate-specific additional exon in the Hinge Region, which is located between LRRD and the serpentine domain. The segment of the Hinge Region encoded by exon10 was previously reported to be only relevant to hLH signaling, as the exon10-deletion receptor exhibits decreased hLH signaling, but unchanged hCG signaling. We designed an advanced homology model of the hormone/LHCGR complex, followed by experimental characterization of relevant fragments in the Hinge Region. In addition, we examined predictions of a helical exon10-encoded conformation by block-wise polyalanine (helix supporting) mutations. These helix preserving modifications showed no effect on hormone induced signaling. However, introduction of a structure-disturbing double-proline mutant LHCGR-Q303P/E305P within the exon10-helix has, in contrast to exon10 deletion, no impact on hLH, but only on hCG signaling. This opposite effect on signaling by hLH and hCG can be explained by distinct sites of hormone interaction in the Hinge Region s. In conclusion, our analysis provides details of the differences between hLH- and hCG-induced signaling that are mainly determined in the L2-beta loop of the hormones and in the Hinge Region of the receptor
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differences in signal activation by lh and hcg are mediated by the lh cg receptor s extracellular Hinge Region
Frontiers in Endocrinology, 2015Co-Authors: Paul Grzesik, Annika Kreuchwig, Claudia Rutz, Jens Furkert, Burkhard Wiesner, Ralf Schuelein, Gunnar Kleinau, Joerg Gromoll, Gerd KrauseAbstract:The human lutropin/choriogonadotropin receptor (LHCGR) can be activated by binding two slightly different gonadotropic glycoprotein hormones, choriogonadotropin (CG) - secreted by the placenta, and lutropin (LH) - produced by the pituitary. They induce different signaling profiles at the LHCGR. This cannot be explained by binding to the receptor's leucine-rich repeat domain (LRRD), as this binding is similar for the two hormones. We therefore speculate that there are previously unknown differences in the hormone/receptor interaction at the extracellular Hinge Region, which might help to understand functional differences between the two hormones. We have therefore performed a detailed study of the binding and action of LH and CG at the LHCGR Hinge Region. We focused on a primate-specific additional exon in the Hinge Region, which is located between LRRD and the serpentine domain. The segment of the Hinge Region encoded by exon10 was previously reported to be only relevant to hLH signaling, as the exon10-deletion receptor exhibits decreased hLH signaling, but unchanged hCG signaling. We designed an advanced homology model of the hormone/LHCGR complex, followed by experimental characterization of relevant fragments in the Hinge Region. In addition, we examined predictions of a helical exon10-encoded conformation by block-wise polyalanine (helix supporting) mutations. These helix preserving modifications showed no effect on hormone induced signaling. However, introduction of a structure-disturbing double-proline mutant LHCGR-Q303P/E305P within the exon10-helix has, in contrast to exon10 deletion, no impact on hLH, but only on hCG signaling. This opposite effect on signaling by hLH and hCG can be explained by distinct sites of hormone interaction in the Hinge Region s. In conclusion, our analysis provides details of the differences between hLH- and hCG-induced signaling that are mainly determined in the L2-beta loop of the hormones and in the Hinge Region of the receptor
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the superagonistic activity of bovine thyroid stimulating hormone tsh and the human tr1401 tsh analog is determined by specific amino acids in the Hinge Region of the human tsh receptor
Journal of Biological Chemistry, 2009Co-Authors: Sandra Mueller, Holger Jaeschke, Gunnar Kleinau, Gerd Krause, Mariusz W Szkudlinski, Ralf PaschkeAbstract:Bovine TSH (bTSH) has a higher affinity to the human TSHR (hTSHR) and a higher signaling activity than human TSH (hTSH). The molecular reasons for these phenomena are unknown. Distinct negatively charged residues (Glu297, Glu303, and Asp382) in the Hinge Region of the hTSHR are known to be important for bTSH binding and signaling. To investigate the potential relevance of these positions for differences between bTSH and hTSH in the interaction to the hTSHR, we determined bTSH- and hTSH-mediated cAMP production of several substitutions at these three Hinge residues. To examine specific variations of hTSH, we also investigated the superagonistic hTSH analog TR1401 (TR1401), whose sequence differs from hTSH by four additional positively charged amino acids that are also present in bTSH. To characterize possible interactions between the acidic hTSHR positions Glu297, Glu303, or Asp382 and the additional basic residues of TR1401, we investigated TR1401 binding and signaling properties. Our data reveal increased cAMP signaling of the hTSHR using TR1401 and bTSH compared with hTSH. Whereas Asp382 seems to be important for bTSH- and TR1401-mediated but not for hTSH-mediated signaling, the substitution E297K exhibits a decreased signaling for all three TSH variants. Interestingly, bTSH and TR1401 showed only a slightly different binding pattern. These observations imply that specific residues of the Hinge Region are mediators of the superagonistic activity of bTSH and TR1401 in contrast to hTSH. Moreover, the simultaneous localization of binding components in the glycoprotein hormone molecule and the receptor Hinge Region permits important reevaluation of interacting hormone receptor domains.
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Extended hormone binding site of the human thyroid stimulating hormone receptor: distinctive acidic residues in the Hinge Region are involved in bovine thyroid stimulating hormone binding and receptor activation.
Journal of Biological Chemistry, 2008Co-Authors: Sandra Mueller, Holger Jaeschke, Ralf Paschke, Gunnar Kleinau, Gerd KrauseAbstract:The human thyroid stimulating hormone receptor (hTSHR) belongs to the glycoprotein hormone receptors that bind the hormones at their large extracellular domain. The extracellular Hinge Region of the TSHR connects the N-terminal leucine-rich repeat domain with the membrane-spanning serpentine domain. From previous studies we reasoned that apart from hormone binding at the leucine-rich repeat domain, additional multiple hormone contacts might exist at the Hinge Region of the TSHR by complementary charge-charge recognition. Here we investigated highly conserved charged residues in the Hinge Region of the TSHR by site-directed mutagenesis to identify amino acids interacting with bovine TSH (bTSH). Indeed, the residues Glu-297, Glu-303, and Asp-382 in the TSHR Hinge Region are essential for bTSH binding and partially for signal transduction. Side chain substitutions showed that the negative charge of Glu-297 and Asp-382 is necessary for recognition of bTSH by the hTSHR. Multiple combinations of alanine mutants of the identified positions revealed an increased negative effect on hormone binding. An assembled model suggests that the deciphered acidic residues form negatively charged patches at the Hinge Region resulting in an extended binding mode for bTSH on the hTSHR. Our data indicate that certain positively charged residues of bTSH might be involved in interaction with the identified negatively charged amino acids of the hTSHR Hinge Region. We demonstrate that the Hinge Region represents an extracellular intermediate connector for both hormone binding and signal transduction of the hTSHR.
Basil Rapoport - One of the best experts on this subject based on the ideXlab platform.
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the thyrotropin receptor Hinge Region as a surrogate ligand identification of loci contributing to the coupling of thyrotropin binding and receptor activation
Endocrinology, 2012Co-Authors: Chun-rong Chen, Sandra M. Mclachlan, Larry M Salazar, Basil RapoportAbstract:The TSH receptor (TSHR) Hinge Region, the least well understood component, bridges the leucine-rich repeat and transmembrane domains. We report data on clusters of Hinge charged residues the mutation of which to Ala is compatible with cell surface expression and normal, or near normal, TSH binding affinity yet with a relative reduction in receptor activation. Mutation to Ala of E409 at the junction with the transmembrane domain was the most potent in uncoupling TSH binding and signal transduction (∼22-fold less sensitive than the wild-type TSHR) and was unique among the residues studied in reducing both the amplitude and the sensitivity of the ligand-induced signal. Unexpectedly, a dual E409A/D410A mutation partially corrected the major suppressive effect of TSHR-E409A. The combined Ala substitution of a cluster of positively charged Hinge residues (K287, K290, K291, R293; termed “K3R1”) synergistically reduced sensitivity to TSH stimulation approximately 21-fold without altering the TSH binding affinity....
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Relationship between Thyrotropin Receptor Hinge Region Proteolytic Posttranslational Modification and Receptor Physiological Function
Molecular Endocrinology, 2011Co-Authors: Sepehr Hamidi, Chun-rong Chen, Yumiko Mizutori-sasai, Sandra M. Mclachlan, Basil RapoportAbstract:The glycoprotein hormone receptor Hinge Region is the least conserved component and the most variable in size; the TSH receptor (TSHR) being the longest (152 amino acids; residues 261–412). The TSHR is also unique among the glycoprotein hormone receptor in undergoing in vivo intramolecular cleavage into disulfide-linked A- and B-subunits with removal of an intervening ‘C-peptide’ Region. Experimentally, Hinge Region amino acids 317–366 (50 residues) can be deleted without alteration in receptor function. However, in vivo, more than 50 amino acids are deleted during TSHR intramolecular cleavage; furthermore, the boundaries of this deleted Region are ragged and poorly defined. Studies to determine the extent to which Hinge Region deletions can be tolerated without affecting receptor function (‘minimal Hinge’) are lacking. Using as a template the functionally normal TSHR with residues 317–366 deleted, progressive downstream extension of deletions revealed residue 371 to be the limit compatible with normal TSH binding and coupling with cAMP signal transduction. Based on the foregoing downstream limit, upstream deletion from residue 307 (307–371 deletion) was also tolerated without functional alteration, as was deletion of residues 303–366. Addressing a related issue regarding the functional role of the TSHR Hinge Region, we observed that downstream Hinge residues 377–384 contribute to coupling ligand binding with cAMP signal transduction. In summary, we report the first evaluation of TSHR function in relation to proteolytic posttranslational Hinge Region modifications. Deletion of TSHR Hinge amino acids 303–366 (64 residues) or 307–371 (65 residues) are the maximum Hinge Region deletions compatible with normal TSHR function.
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a monoclonal antibody with thyrotropin tsh receptor inverse agonist and tsh antagonist activities binds to the receptor Hinge Region as well as to the leucine rich domain
Endocrinology, 2009Co-Authors: Chun-rong Chen, Sandra M. Mclachlan, Basil RapoportAbstract:Monoclonal antibody CS-17 is a TSH receptor (TSHR) inverse agonist (suppresses constitutive activity) and a TSH antagonist. Elucidation of the CS-17 epitope will provide insight into TSHR structure and function. Present information on its epitope conflicts with recent data regarding another TSHR inverse agonist antibody. To characterize further the CS-17 epitope, we exploited the observation that CS-17 does not recognize a chimeric receptor with TSHR Hinge Region residues 261–289 replaced with homologous rat LH receptor residues (13 mismatches). We generated individual and double TSHR mutations corresponding to these mismatches. On flow cytometry, only T273L/R274V reduced CS-17 recognition. No mutation affected TSH-stimulated cAMP generation. Because the immunogen for CS-17 generation was highly glycosylated, we also investigated whether the glycan moiety at N198, topologically adjacent to Y195 (a previously identified epitopic component), could contribute to the CS-17 epitope. Elimination of this N-linked glycan (mutations of N198 and T200) abrogated CS-17 binding without altering TSH responsiveness. However, studies with tunicamycin suggested that these mutations affected CS-17 binding by altering the polypeptide backbone rather than eliminating the glycan moiety. TSHR residues N198 and T200, like Y195, are on the convex facet of the leucine-rich domain. In summary, the present data indicate that the discontinuous epitope of CS-17, a TSHR inverse agonist and TSH antagonist, includes a component in the Hinge Region as well as the convex surface of the TSHR leucine-rich domain. These findings expand our present concept of glycoprotein hormone binding and function.
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the thyrotropin receptor Hinge Region is not simply a scaffold for the leucine rich domain but contributes to ligand binding and signal transduction
Molecular Endocrinology, 2008Co-Authors: Yumiko Mizutori, Chun-rong Chen, Sandra M. Mclachlan, Basil RapoportAbstract:The glycoprotein hormone receptor Hinge Region connects the leucine-rich and transmembrane domains. The prevalent concept is that the Hinge does not play a significant role in ligand binding and signal transduction. Portions of the Hinge are redundant and can be deleted by mutagenesis or are absent in certain species. A minimal Hinge will be more amenable to future investigation of its structure and function. We, therefore, combined and progressively extended previous deletions (Delta) in the TSH receptor (TSHR) Hinge Region (residues 277-418). TSHRDelta287-366, Delta287-371, Delta287-376, and Delta287-384 progressively lost their response to TSH stimulation of cAMP generation in intact cells, consistent with a progressive loss of TSH binding. The longest deletion (TSHRDelta287-384), reducing the Hinge Region from 141 to 43 amino acids, totally lost both functions. Surprisingly, however, with deletions extending from residues 371-384, constitutive (ligand-independent) activity increased severalfold, reversing the suppressive (inverse agonist) effect of the TSHR extracellular domain. TSHR-activating point mutations I486F and I568T in the first and second extracellular loops (especially the former) had reduced activity on a background of TSHRDelta287-371. In summary, our data support the concept that the TSHR Hinge contributes significantly to ligand binding affinity and signal transduction. Residues within the Hinge, particularly between positions 371-384, appear involved in ectodomain inverse agonist activity. In addition, the Hinge is necessary for functionality of activating mutations in the first and second extracellular loops. Rather than being an inert linker between the leucine-rich and transmembrane domains, the TSHR Hinge is a signaling-specificity domain.
Ralf Paschke - One of the best experts on this subject based on the ideXlab platform.
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The Hinge Region: an important receptor component for GPHR function
Trends in Endocrinology & Metabolism, 2010Co-Authors: Sandra Mueller, Holger Jaeschke, Robert Günther, Ralf PaschkeAbstract:Glycoprotein hormone receptors (GPHRs) are members of the seven-transmembrane-spanning receptor family characterized by a large ectodomain. The Hinge Region belongs to a part of the GPHR ectodomain for which the three-dimensional structure has not yet been deciphered, leaving important questions unanswered concerning ligand binding and GPHR activation. Recent publications indicate that specific residues of the Hinge Region mediate hormone binding, receptor activation and/or intramolecular signaling for the three GPHRs, emphasizing the importance of this Region. Based on these findings, the Hinge Region is involved at least in part in hormone binding and receptor activation. This review summarizes functional data regarding the Hinge Region, demonstrating that this receptor portion represents a link between ligand binding and subsequent GPHR activation.
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the superagonistic activity of bovine thyroid stimulating hormone tsh and the human tr1401 tsh analog is determined by specific amino acids in the Hinge Region of the human tsh receptor
Journal of Biological Chemistry, 2009Co-Authors: Sandra Mueller, Holger Jaeschke, Gunnar Kleinau, Gerd Krause, Mariusz W Szkudlinski, Ralf PaschkeAbstract:Bovine TSH (bTSH) has a higher affinity to the human TSHR (hTSHR) and a higher signaling activity than human TSH (hTSH). The molecular reasons for these phenomena are unknown. Distinct negatively charged residues (Glu297, Glu303, and Asp382) in the Hinge Region of the hTSHR are known to be important for bTSH binding and signaling. To investigate the potential relevance of these positions for differences between bTSH and hTSH in the interaction to the hTSHR, we determined bTSH- and hTSH-mediated cAMP production of several substitutions at these three Hinge residues. To examine specific variations of hTSH, we also investigated the superagonistic hTSH analog TR1401 (TR1401), whose sequence differs from hTSH by four additional positively charged amino acids that are also present in bTSH. To characterize possible interactions between the acidic hTSHR positions Glu297, Glu303, or Asp382 and the additional basic residues of TR1401, we investigated TR1401 binding and signaling properties. Our data reveal increased cAMP signaling of the hTSHR using TR1401 and bTSH compared with hTSH. Whereas Asp382 seems to be important for bTSH- and TR1401-mediated but not for hTSH-mediated signaling, the substitution E297K exhibits a decreased signaling for all three TSH variants. Interestingly, bTSH and TR1401 showed only a slightly different binding pattern. These observations imply that specific residues of the Hinge Region are mediators of the superagonistic activity of bTSH and TR1401 in contrast to hTSH. Moreover, the simultaneous localization of binding components in the glycoprotein hormone molecule and the receptor Hinge Region permits important reevaluation of interacting hormone receptor domains.
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Extended hormone binding site of the human thyroid stimulating hormone receptor: distinctive acidic residues in the Hinge Region are involved in bovine thyroid stimulating hormone binding and receptor activation.
Journal of Biological Chemistry, 2008Co-Authors: Sandra Mueller, Holger Jaeschke, Ralf Paschke, Gunnar Kleinau, Gerd KrauseAbstract:The human thyroid stimulating hormone receptor (hTSHR) belongs to the glycoprotein hormone receptors that bind the hormones at their large extracellular domain. The extracellular Hinge Region of the TSHR connects the N-terminal leucine-rich repeat domain with the membrane-spanning serpentine domain. From previous studies we reasoned that apart from hormone binding at the leucine-rich repeat domain, additional multiple hormone contacts might exist at the Hinge Region of the TSHR by complementary charge-charge recognition. Here we investigated highly conserved charged residues in the Hinge Region of the TSHR by site-directed mutagenesis to identify amino acids interacting with bovine TSH (bTSH). Indeed, the residues Glu-297, Glu-303, and Asp-382 in the TSHR Hinge Region are essential for bTSH binding and partially for signal transduction. Side chain substitutions showed that the negative charge of Glu-297 and Asp-382 is necessary for recognition of bTSH by the hTSHR. Multiple combinations of alanine mutants of the identified positions revealed an increased negative effect on hormone binding. An assembled model suggests that the deciphered acidic residues form negatively charged patches at the Hinge Region resulting in an extended binding mode for bTSH on the hTSHR. Our data indicate that certain positively charged residues of bTSH might be involved in interaction with the identified negatively charged amino acids of the hTSHR Hinge Region. We demonstrate that the Hinge Region represents an extracellular intermediate connector for both hormone binding and signal transduction of the hTSHR.
Gunnar Kleinau - One of the best experts on this subject based on the ideXlab platform.
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Differences in Signal Activation by LH and hCG are Mediated by the LH/CG Receptor’s Extracellular Hinge Region
Frontiers in Endocrinology, 2015Co-Authors: Paul Grzesik, Annika Kreuchwig, Claudia Rutz, Jens Furkert, Burkhard Wiesner, Ralf Schuelein, Gunnar Kleinau, Joerg Gromoll, Gerd KrauseAbstract:The human lutropin/choriogonadotropin receptor (LHCGR) can be activated by binding two slightly different gonadotropic glycoprotein hormones, choriogonadotropin (CG) - secreted by the placenta, and lutropin (LH) - produced by the pituitary. They induce different signaling profiles at the LHCGR. This cannot be explained by binding to the receptor's leucine-rich repeat domain (LRRD), as this binding is similar for the two hormones. We therefore speculate that there are previously unknown differences in the hormone/receptor interaction at the extracellular Hinge Region, which might help to understand functional differences between the two hormones. We have therefore performed a detailed study of the binding and action of LH and CG at the LHCGR Hinge Region. We focused on a primate-specific additional exon in the Hinge Region, which is located between LRRD and the serpentine domain. The segment of the Hinge Region encoded by exon10 was previously reported to be only relevant to hLH signaling, as the exon10-deletion receptor exhibits decreased hLH signaling, but unchanged hCG signaling. We designed an advanced homology model of the hormone/LHCGR complex, followed by experimental characterization of relevant fragments in the Hinge Region. In addition, we examined predictions of a helical exon10-encoded conformation by block-wise polyalanine (helix supporting) mutations. These helix preserving modifications showed no effect on hormone induced signaling. However, introduction of a structure-disturbing double-proline mutant LHCGR-Q303P/E305P within the exon10-helix has, in contrast to exon10 deletion, no impact on hLH, but only on hCG signaling. This opposite effect on signaling by hLH and hCG can be explained by distinct sites of hormone interaction in the Hinge Region s. In conclusion, our analysis provides details of the differences between hLH- and hCG-induced signaling that are mainly determined in the L2-beta loop of the hormones and in the Hinge Region of the receptor
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differences in signal activation by lh and hcg are mediated by the lh cg receptor s extracellular Hinge Region
Frontiers in Endocrinology, 2015Co-Authors: Paul Grzesik, Annika Kreuchwig, Claudia Rutz, Jens Furkert, Burkhard Wiesner, Ralf Schuelein, Gunnar Kleinau, Joerg Gromoll, Gerd KrauseAbstract:The human lutropin/choriogonadotropin receptor (LHCGR) can be activated by binding two slightly different gonadotropic glycoprotein hormones, choriogonadotropin (CG) - secreted by the placenta, and lutropin (LH) - produced by the pituitary. They induce different signaling profiles at the LHCGR. This cannot be explained by binding to the receptor's leucine-rich repeat domain (LRRD), as this binding is similar for the two hormones. We therefore speculate that there are previously unknown differences in the hormone/receptor interaction at the extracellular Hinge Region, which might help to understand functional differences between the two hormones. We have therefore performed a detailed study of the binding and action of LH and CG at the LHCGR Hinge Region. We focused on a primate-specific additional exon in the Hinge Region, which is located between LRRD and the serpentine domain. The segment of the Hinge Region encoded by exon10 was previously reported to be only relevant to hLH signaling, as the exon10-deletion receptor exhibits decreased hLH signaling, but unchanged hCG signaling. We designed an advanced homology model of the hormone/LHCGR complex, followed by experimental characterization of relevant fragments in the Hinge Region. In addition, we examined predictions of a helical exon10-encoded conformation by block-wise polyalanine (helix supporting) mutations. These helix preserving modifications showed no effect on hormone induced signaling. However, introduction of a structure-disturbing double-proline mutant LHCGR-Q303P/E305P within the exon10-helix has, in contrast to exon10 deletion, no impact on hLH, but only on hCG signaling. This opposite effect on signaling by hLH and hCG can be explained by distinct sites of hormone interaction in the Hinge Region s. In conclusion, our analysis provides details of the differences between hLH- and hCG-induced signaling that are mainly determined in the L2-beta loop of the hormones and in the Hinge Region of the receptor
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the superagonistic activity of bovine thyroid stimulating hormone tsh and the human tr1401 tsh analog is determined by specific amino acids in the Hinge Region of the human tsh receptor
Journal of Biological Chemistry, 2009Co-Authors: Sandra Mueller, Holger Jaeschke, Gunnar Kleinau, Gerd Krause, Mariusz W Szkudlinski, Ralf PaschkeAbstract:Bovine TSH (bTSH) has a higher affinity to the human TSHR (hTSHR) and a higher signaling activity than human TSH (hTSH). The molecular reasons for these phenomena are unknown. Distinct negatively charged residues (Glu297, Glu303, and Asp382) in the Hinge Region of the hTSHR are known to be important for bTSH binding and signaling. To investigate the potential relevance of these positions for differences between bTSH and hTSH in the interaction to the hTSHR, we determined bTSH- and hTSH-mediated cAMP production of several substitutions at these three Hinge residues. To examine specific variations of hTSH, we also investigated the superagonistic hTSH analog TR1401 (TR1401), whose sequence differs from hTSH by four additional positively charged amino acids that are also present in bTSH. To characterize possible interactions between the acidic hTSHR positions Glu297, Glu303, or Asp382 and the additional basic residues of TR1401, we investigated TR1401 binding and signaling properties. Our data reveal increased cAMP signaling of the hTSHR using TR1401 and bTSH compared with hTSH. Whereas Asp382 seems to be important for bTSH- and TR1401-mediated but not for hTSH-mediated signaling, the substitution E297K exhibits a decreased signaling for all three TSH variants. Interestingly, bTSH and TR1401 showed only a slightly different binding pattern. These observations imply that specific residues of the Hinge Region are mediators of the superagonistic activity of bTSH and TR1401 in contrast to hTSH. Moreover, the simultaneous localization of binding components in the glycoprotein hormone molecule and the receptor Hinge Region permits important reevaluation of interacting hormone receptor domains.
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Extended hormone binding site of the human thyroid stimulating hormone receptor: distinctive acidic residues in the Hinge Region are involved in bovine thyroid stimulating hormone binding and receptor activation.
Journal of Biological Chemistry, 2008Co-Authors: Sandra Mueller, Holger Jaeschke, Ralf Paschke, Gunnar Kleinau, Gerd KrauseAbstract:The human thyroid stimulating hormone receptor (hTSHR) belongs to the glycoprotein hormone receptors that bind the hormones at their large extracellular domain. The extracellular Hinge Region of the TSHR connects the N-terminal leucine-rich repeat domain with the membrane-spanning serpentine domain. From previous studies we reasoned that apart from hormone binding at the leucine-rich repeat domain, additional multiple hormone contacts might exist at the Hinge Region of the TSHR by complementary charge-charge recognition. Here we investigated highly conserved charged residues in the Hinge Region of the TSHR by site-directed mutagenesis to identify amino acids interacting with bovine TSH (bTSH). Indeed, the residues Glu-297, Glu-303, and Asp-382 in the TSHR Hinge Region are essential for bTSH binding and partially for signal transduction. Side chain substitutions showed that the negative charge of Glu-297 and Asp-382 is necessary for recognition of bTSH by the hTSHR. Multiple combinations of alanine mutants of the identified positions revealed an increased negative effect on hormone binding. An assembled model suggests that the deciphered acidic residues form negatively charged patches at the Hinge Region resulting in an extended binding mode for bTSH on the hTSHR. Our data indicate that certain positively charged residues of bTSH might be involved in interaction with the identified negatively charged amino acids of the hTSHR Hinge Region. We demonstrate that the Hinge Region represents an extracellular intermediate connector for both hormone binding and signal transduction of the hTSHR.
Sandra Mueller - One of the best experts on this subject based on the ideXlab platform.
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The Hinge Region: an important receptor component for GPHR function
Trends in Endocrinology & Metabolism, 2010Co-Authors: Sandra Mueller, Holger Jaeschke, Robert Günther, Ralf PaschkeAbstract:Glycoprotein hormone receptors (GPHRs) are members of the seven-transmembrane-spanning receptor family characterized by a large ectodomain. The Hinge Region belongs to a part of the GPHR ectodomain for which the three-dimensional structure has not yet been deciphered, leaving important questions unanswered concerning ligand binding and GPHR activation. Recent publications indicate that specific residues of the Hinge Region mediate hormone binding, receptor activation and/or intramolecular signaling for the three GPHRs, emphasizing the importance of this Region. Based on these findings, the Hinge Region is involved at least in part in hormone binding and receptor activation. This review summarizes functional data regarding the Hinge Region, demonstrating that this receptor portion represents a link between ligand binding and subsequent GPHR activation.
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the superagonistic activity of bovine thyroid stimulating hormone tsh and the human tr1401 tsh analog is determined by specific amino acids in the Hinge Region of the human tsh receptor
Journal of Biological Chemistry, 2009Co-Authors: Sandra Mueller, Holger Jaeschke, Gunnar Kleinau, Gerd Krause, Mariusz W Szkudlinski, Ralf PaschkeAbstract:Bovine TSH (bTSH) has a higher affinity to the human TSHR (hTSHR) and a higher signaling activity than human TSH (hTSH). The molecular reasons for these phenomena are unknown. Distinct negatively charged residues (Glu297, Glu303, and Asp382) in the Hinge Region of the hTSHR are known to be important for bTSH binding and signaling. To investigate the potential relevance of these positions for differences between bTSH and hTSH in the interaction to the hTSHR, we determined bTSH- and hTSH-mediated cAMP production of several substitutions at these three Hinge residues. To examine specific variations of hTSH, we also investigated the superagonistic hTSH analog TR1401 (TR1401), whose sequence differs from hTSH by four additional positively charged amino acids that are also present in bTSH. To characterize possible interactions between the acidic hTSHR positions Glu297, Glu303, or Asp382 and the additional basic residues of TR1401, we investigated TR1401 binding and signaling properties. Our data reveal increased cAMP signaling of the hTSHR using TR1401 and bTSH compared with hTSH. Whereas Asp382 seems to be important for bTSH- and TR1401-mediated but not for hTSH-mediated signaling, the substitution E297K exhibits a decreased signaling for all three TSH variants. Interestingly, bTSH and TR1401 showed only a slightly different binding pattern. These observations imply that specific residues of the Hinge Region are mediators of the superagonistic activity of bTSH and TR1401 in contrast to hTSH. Moreover, the simultaneous localization of binding components in the glycoprotein hormone molecule and the receptor Hinge Region permits important reevaluation of interacting hormone receptor domains.
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Extended hormone binding site of the human thyroid stimulating hormone receptor: distinctive acidic residues in the Hinge Region are involved in bovine thyroid stimulating hormone binding and receptor activation.
Journal of Biological Chemistry, 2008Co-Authors: Sandra Mueller, Holger Jaeschke, Ralf Paschke, Gunnar Kleinau, Gerd KrauseAbstract:The human thyroid stimulating hormone receptor (hTSHR) belongs to the glycoprotein hormone receptors that bind the hormones at their large extracellular domain. The extracellular Hinge Region of the TSHR connects the N-terminal leucine-rich repeat domain with the membrane-spanning serpentine domain. From previous studies we reasoned that apart from hormone binding at the leucine-rich repeat domain, additional multiple hormone contacts might exist at the Hinge Region of the TSHR by complementary charge-charge recognition. Here we investigated highly conserved charged residues in the Hinge Region of the TSHR by site-directed mutagenesis to identify amino acids interacting with bovine TSH (bTSH). Indeed, the residues Glu-297, Glu-303, and Asp-382 in the TSHR Hinge Region are essential for bTSH binding and partially for signal transduction. Side chain substitutions showed that the negative charge of Glu-297 and Asp-382 is necessary for recognition of bTSH by the hTSHR. Multiple combinations of alanine mutants of the identified positions revealed an increased negative effect on hormone binding. An assembled model suggests that the deciphered acidic residues form negatively charged patches at the Hinge Region resulting in an extended binding mode for bTSH on the hTSHR. Our data indicate that certain positively charged residues of bTSH might be involved in interaction with the identified negatively charged amino acids of the hTSHR Hinge Region. We demonstrate that the Hinge Region represents an extracellular intermediate connector for both hormone binding and signal transduction of the hTSHR.