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Walter Rosenthal - One of the best experts on this subject based on the ideXlab platform.
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Rescue of a Nephrogenic Diabetes Insipidus-causing Vasopressin V2 Receptor Mutant by Cell-penetrating Peptides
The Journal of biological chemistry, 2007Co-Authors: Morad Oueslati, Burkhard Wiesner, Walter Rosenthal, Ricardo Hermosilla, Eva Schönenberger, Viola Oorschot, Michael Beyermann, Antje Schmidt, Judith Klumperman, Ralf SchüleinAbstract:Abstract Mutant membrane proteins are frequently retained in the early secretory pathway by a quality control system, thereby causing disease. An example are mutants of the Vasopressin V2 Receptor (V2R) leading to nephrogenic diabetes insipidus. Transport-defective V2Rs fall into two classes: those retained exclusively in the endoplasmic reticulum (ER) and those reaching post-ER compartments such as the ER/Golgi intermediate compartment. Although numerous chemical or pharmacological chaperones that rescue the transport of ER-retained membrane proteins are known, substances acting specifically in post-ER compartments have not been described as yet. Using the L62P (ER-retained) and Y205C (reaching post-ER compartments) mutants of the V2R as a model, we show here that the cell-penetrating peptide penetratin and its synthetic analog KLAL rescue the transport of the Y205C mutant. In contrast, the location of the L62P mutant is not influenced by either peptide because the peptides are unable to enter the ER. We also show data indicating that the peptide-mediated transport rescue is associated with an increase in cytosolic Ca2+ concentrations. Thus, we describe a new class of substances influencing protein transport specifically in post-ER compartments.
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The hydrophobic amino acid residues in the membrane-proximal C tail of the G protein-coupled Vasopressin V2 Receptor are necessary for transport-competent Receptor folding
FEBS letters, 2005Co-Authors: Anja Thielen, Walter Rosenthal, Alexander Oksche, Morad Oueslati, Ricardo Hermosilla, Gerd Krause, Ralf SchüleinAbstract:It is believed that the membrane-proximal C tail of the G protein-coupled Receptors forms an additional alpha helix with amphipathic properties (helix 8). It was previously shown for the Vasopressin V2 Receptor (V2R) that a conserved dileucine motif (L339, L340) in this putative helix 8 is necessary for endoplasmic reticulum (ER) to Golgi transfer of the Receptor. Here, we demonstrate that the other hydrophobic residues forming the non-polar side of this helix (F328, V332 and L336) are also transport-relevant. In contrast, the multiple serine residues contributing to the more hydrophilic side (S330, S331, S333, S334, S338) do not influence Receptor trafficking. In addition, we show unambiguously by the use of pharmacological chaperones that the hydrophobic residues of the putative helix 8 do not form a transport signal necessary for Receptor sorting into ER to Golgi vesicles. Instead, they are necessary to establish a transport-competent folding state in the early secretory pathway.
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Functional rescue of the nephrogenic diabetes insipidus-causing Vasopressin V2 Receptor mutants G185C and R202C by a second site suppressor mutation.
The Journal of biological chemistry, 2000Co-Authors: Ralf Schülein, Gerd Krause, Kerstin Zühlke, Walter RosenthalAbstract:Abstract Mutations in the gene of the G protein-coupled Vasopressin V2 Receptor (V2 Receptor) cause X-linked nephrogenic diabetes insipidus (NDI). Most of the missense mutations on the extracellular face of the Receptor introduce additional cysteine residues. Several groups have proposed that these residues might disrupt the conserved disulfide bond of the V2 Receptor. To test this hypothesis, we first calculated a structure model of the extracellular Receptor domains. The model suggests that the additional cysteine residues may form a second disulfide bond with the free, nonconserved extracellular cysteine residue Cys-195 rather than impairing the conserved bond. To address this question experimentally, we used the NDI-causing mutant Receptors G185C and R202C. Their Cys-195 residues were replaced by alanine to eliminate the hypothetical second disulfide bonds. This second site mutation led to functional rescue of both NDI-causing mutant Receptors, strongly suggesting that the second disulfide bonds are indeed formed. Furthermore we show that residue Cys-195, which is sensitive to “additional cysteine” mutations, is not conserved among the V2 Receptors of other species and that the presence of an uneven number of extracellular cysteine residues, as in the human V2 Receptor, is rare among class I G protein-coupled Receptors.
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The role of conserved extracellular cysteine residues in Vasopressin V2 Receptor function and properties of two naturally occurring mutant Receptors with additional extracellular cysteine residues.
FEBS letters, 2000Co-Authors: Ralf Schülein, Alexander Oksche, Ricardo Hermosilla, Kerstin Zühlke, Jens Furkert, Walter RosenthalAbstract:Abstract The G protein-coupled Vasopressin V2 Receptor (V2 Receptor) contains a pair of conserved cysteine residues (C112 and C192) which are thought to form a disulfide bond between the first and second extracellular loops. The conserved cysteine residues were found to be important for the correct formation of the ligand binding domain of some G protein-coupled Receptors. Here we have assessed the properties of the V2 Receptor after site-directed mutagenesis of its conserved cysteine residues in transiently transfected human embryonic kidney (HEK 293) cells. Mutant Receptors (C112S, C112A and C192S, C192A) were non-functional and located mostly in the cell’s interior. The conserved cysteine residues of the V2 Receptor are thus not only important for the structure of the ligand binding domain but also for efficient intracellular Receptor transport. In addition to the functional significance of the conserved cysteine residues, we have also analyzed the defects of two mutant V2 Receptors which cause X-linked nephrogenic diabetes insipidus (NDI) by the introduction of additional cysteine residues into the second extracellular loop (mutants G185C, R202C). These mutations are assumed to impair normal disulfide bond formation. Mutant Receptor G185C and R202C were efficiently transported to the plasma membrane but were defective in ligand binding. Only in the case of the mutant Receptor R202C, the more sensitive adenylyl cyclase activity assay revealed Vasopressin-stimulated cAMP formation with a 35-fold increased EC50 value and with a reduced ECmax, indicating that ligand binding is not completely abolished. Taking the unaffected intracellular transport of both NDI-causing mutant Receptors into account, our results indicate that the observed impairment of ligand binding by the additional cysteine residues is not due to the prevention of disulfide bond formation between the conserved cysteine residues.
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Polarized expression of the Vasopressin V2 Receptor in Madin-Darby canine kidney cells.
Kidney international, 1999Co-Authors: Bettina Andersen-beckh, Marcel Dehe, Ralf Schülein, Burkhard Wiesner, Claudia Rutz, Ursula Liebenhoff, Walter Rosenthal, Alexander OkscheAbstract:Polarized expression of the Vasopressin V2 Receptor in Madin-Darby canine kidney cells. Background The Vasopressin V2 Receptor is expressed in the polarized principal cell of the renal collecting duct. Inactivating mutations of the Vasopressin V2 Receptor gene cause X-linked nephrogenic diabetes insipidus (NDI). Most of the mutant V2 Receptors show transport defects, as analyzed in non-polarized cells, but data pertaining to polarized cells have not previously been presented. Methods Madin-Darby canine kidney cell (MDCK) II clones stably expressing c-myc–tagged human V2 Receptors were characterized for [ 3 H]-arginine Vasopressin (AVP)-binding and AVP-sensitive adenylyl cyclase activity. The V2 Receptors were immunocytochemically localized using the tyramide signal amplification technique in conjunction with an anti–c-myc antibody. Results The introduction of the c-myc epitope at the N- or C-terminus did not affect the functional properties of the V2 Receptor expressed in MDCK II clones. However, the use of standard immunofluorescence methodology for these MDCK II clones yielded only weak signals. With the tyramide signal amplification technique, strong signals were obtained, showing the V2 Receptor to be mainly localized within the lateral and, to a minor extent, apical membrane. In MDCK II clones stably expressing the c-myc–tagged V2 Receptor NDI mutant L44P, fluorescent signals were found exclusively within the cell. Conclusion The wild-type V2 Receptor is expressed mainly in the lateral membrane, whereas the L44P mutant is completely retained within the cell. In conjunction with tyramide signal amplification, MDCK II cells constitute a suitable model for the analysis of transport-defective mutants of the V2 Receptor.
Ralf Schülein - One of the best experts on this subject based on the ideXlab platform.
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Rescue of a Nephrogenic Diabetes Insipidus-causing Vasopressin V2 Receptor Mutant by Cell-penetrating Peptides
The Journal of biological chemistry, 2007Co-Authors: Morad Oueslati, Burkhard Wiesner, Walter Rosenthal, Ricardo Hermosilla, Eva Schönenberger, Viola Oorschot, Michael Beyermann, Antje Schmidt, Judith Klumperman, Ralf SchüleinAbstract:Abstract Mutant membrane proteins are frequently retained in the early secretory pathway by a quality control system, thereby causing disease. An example are mutants of the Vasopressin V2 Receptor (V2R) leading to nephrogenic diabetes insipidus. Transport-defective V2Rs fall into two classes: those retained exclusively in the endoplasmic reticulum (ER) and those reaching post-ER compartments such as the ER/Golgi intermediate compartment. Although numerous chemical or pharmacological chaperones that rescue the transport of ER-retained membrane proteins are known, substances acting specifically in post-ER compartments have not been described as yet. Using the L62P (ER-retained) and Y205C (reaching post-ER compartments) mutants of the V2R as a model, we show here that the cell-penetrating peptide penetratin and its synthetic analog KLAL rescue the transport of the Y205C mutant. In contrast, the location of the L62P mutant is not influenced by either peptide because the peptides are unable to enter the ER. We also show data indicating that the peptide-mediated transport rescue is associated with an increase in cytosolic Ca2+ concentrations. Thus, we describe a new class of substances influencing protein transport specifically in post-ER compartments.
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The hydrophobic amino acid residues in the membrane-proximal C tail of the G protein-coupled Vasopressin V2 Receptor are necessary for transport-competent Receptor folding
FEBS letters, 2005Co-Authors: Anja Thielen, Walter Rosenthal, Alexander Oksche, Morad Oueslati, Ricardo Hermosilla, Gerd Krause, Ralf SchüleinAbstract:It is believed that the membrane-proximal C tail of the G protein-coupled Receptors forms an additional alpha helix with amphipathic properties (helix 8). It was previously shown for the Vasopressin V2 Receptor (V2R) that a conserved dileucine motif (L339, L340) in this putative helix 8 is necessary for endoplasmic reticulum (ER) to Golgi transfer of the Receptor. Here, we demonstrate that the other hydrophobic residues forming the non-polar side of this helix (F328, V332 and L336) are also transport-relevant. In contrast, the multiple serine residues contributing to the more hydrophilic side (S330, S331, S333, S334, S338) do not influence Receptor trafficking. In addition, we show unambiguously by the use of pharmacological chaperones that the hydrophobic residues of the putative helix 8 do not form a transport signal necessary for Receptor sorting into ER to Golgi vesicles. Instead, they are necessary to establish a transport-competent folding state in the early secretory pathway.
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Sorting Functions of the Individual Cytoplasmic Domains of the G Protein-Coupled Vasopressin V2 Receptor in Madin Darby Canine Kidney Epithelial Cells
Molecular pharmacology, 2001Co-Authors: Ricardo Hermosilla, Ralf SchüleinAbstract:Previous studies have shown that the G protein-coupled human Vasopressin V2 Receptor (V2 Receptor) is expressed predominantly in the basolateral membrane of Madin Darby canine kidney type II (MDCKII) epithelial cells at steady state. Here we have assessed the influence of the individual cytoplasmic domains of the V2 Receptor on polarized sorting in MDCKII cells. The second (ICL2) and third (ICL3) intracellular loops and the C-terminal tail were fused separately to a green fluorescent protein-tagged Receptor fragment comprising the first transmembrane domain and flanking regions. We show that the ICL2 domain of the V2 Receptor alone promotes basolateral cell surface expression and thus seems to contain the basolateral sorting signal of the V2 Receptor. Fusion of the other cytoplasmic domains, however, does not lead to a randomized cell surface expression. The C-terminal tail of the V2 Receptor promotes apical targeting. Fusion of ICL3 leads to a Receptor fragment that is retained in the endoplasmic reticulum (ER). The results are consistent with a model in which the V2 Receptor contains signals for both apical and basolateral cell surface expression, the latter being dominant. Furthermore, ICL3 may contain a retinoid X Receptor ER retention signal, which is not accessible in the correctly folded full-length Receptor but which is unmasked when ICL3 is fused alone.
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Functional rescue of the nephrogenic diabetes insipidus-causing Vasopressin V2 Receptor mutants G185C and R202C by a second site suppressor mutation.
The Journal of biological chemistry, 2000Co-Authors: Ralf Schülein, Gerd Krause, Kerstin Zühlke, Walter RosenthalAbstract:Abstract Mutations in the gene of the G protein-coupled Vasopressin V2 Receptor (V2 Receptor) cause X-linked nephrogenic diabetes insipidus (NDI). Most of the missense mutations on the extracellular face of the Receptor introduce additional cysteine residues. Several groups have proposed that these residues might disrupt the conserved disulfide bond of the V2 Receptor. To test this hypothesis, we first calculated a structure model of the extracellular Receptor domains. The model suggests that the additional cysteine residues may form a second disulfide bond with the free, nonconserved extracellular cysteine residue Cys-195 rather than impairing the conserved bond. To address this question experimentally, we used the NDI-causing mutant Receptors G185C and R202C. Their Cys-195 residues were replaced by alanine to eliminate the hypothetical second disulfide bonds. This second site mutation led to functional rescue of both NDI-causing mutant Receptors, strongly suggesting that the second disulfide bonds are indeed formed. Furthermore we show that residue Cys-195, which is sensitive to “additional cysteine” mutations, is not conserved among the V2 Receptors of other species and that the presence of an uneven number of extracellular cysteine residues, as in the human V2 Receptor, is rare among class I G protein-coupled Receptors.
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The role of conserved extracellular cysteine residues in Vasopressin V2 Receptor function and properties of two naturally occurring mutant Receptors with additional extracellular cysteine residues.
FEBS letters, 2000Co-Authors: Ralf Schülein, Alexander Oksche, Ricardo Hermosilla, Kerstin Zühlke, Jens Furkert, Walter RosenthalAbstract:Abstract The G protein-coupled Vasopressin V2 Receptor (V2 Receptor) contains a pair of conserved cysteine residues (C112 and C192) which are thought to form a disulfide bond between the first and second extracellular loops. The conserved cysteine residues were found to be important for the correct formation of the ligand binding domain of some G protein-coupled Receptors. Here we have assessed the properties of the V2 Receptor after site-directed mutagenesis of its conserved cysteine residues in transiently transfected human embryonic kidney (HEK 293) cells. Mutant Receptors (C112S, C112A and C192S, C192A) were non-functional and located mostly in the cell’s interior. The conserved cysteine residues of the V2 Receptor are thus not only important for the structure of the ligand binding domain but also for efficient intracellular Receptor transport. In addition to the functional significance of the conserved cysteine residues, we have also analyzed the defects of two mutant V2 Receptors which cause X-linked nephrogenic diabetes insipidus (NDI) by the introduction of additional cysteine residues into the second extracellular loop (mutants G185C, R202C). These mutations are assumed to impair normal disulfide bond formation. Mutant Receptor G185C and R202C were efficiently transported to the plasma membrane but were defective in ligand binding. Only in the case of the mutant Receptor R202C, the more sensitive adenylyl cyclase activity assay revealed Vasopressin-stimulated cAMP formation with a 35-fold increased EC50 value and with a reduced ECmax, indicating that ligand binding is not completely abolished. Taking the unaffected intracellular transport of both NDI-causing mutant Receptors into account, our results indicate that the observed impairment of ligand binding by the additional cysteine residues is not due to the prevention of disulfide bond formation between the conserved cysteine residues.
Alexander Oksche - One of the best experts on this subject based on the ideXlab platform.
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The hydrophobic amino acid residues in the membrane-proximal C tail of the G protein-coupled Vasopressin V2 Receptor are necessary for transport-competent Receptor folding
FEBS letters, 2005Co-Authors: Anja Thielen, Walter Rosenthal, Alexander Oksche, Morad Oueslati, Ricardo Hermosilla, Gerd Krause, Ralf SchüleinAbstract:It is believed that the membrane-proximal C tail of the G protein-coupled Receptors forms an additional alpha helix with amphipathic properties (helix 8). It was previously shown for the Vasopressin V2 Receptor (V2R) that a conserved dileucine motif (L339, L340) in this putative helix 8 is necessary for endoplasmic reticulum (ER) to Golgi transfer of the Receptor. Here, we demonstrate that the other hydrophobic residues forming the non-polar side of this helix (F328, V332 and L336) are also transport-relevant. In contrast, the multiple serine residues contributing to the more hydrophilic side (S330, S331, S333, S334, S338) do not influence Receptor trafficking. In addition, we show unambiguously by the use of pharmacological chaperones that the hydrophobic residues of the putative helix 8 do not form a transport signal necessary for Receptor sorting into ER to Golgi vesicles. Instead, they are necessary to establish a transport-competent folding state in the early secretory pathway.
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The role of conserved extracellular cysteine residues in Vasopressin V2 Receptor function and properties of two naturally occurring mutant Receptors with additional extracellular cysteine residues.
FEBS letters, 2000Co-Authors: Ralf Schülein, Alexander Oksche, Ricardo Hermosilla, Kerstin Zühlke, Jens Furkert, Walter RosenthalAbstract:Abstract The G protein-coupled Vasopressin V2 Receptor (V2 Receptor) contains a pair of conserved cysteine residues (C112 and C192) which are thought to form a disulfide bond between the first and second extracellular loops. The conserved cysteine residues were found to be important for the correct formation of the ligand binding domain of some G protein-coupled Receptors. Here we have assessed the properties of the V2 Receptor after site-directed mutagenesis of its conserved cysteine residues in transiently transfected human embryonic kidney (HEK 293) cells. Mutant Receptors (C112S, C112A and C192S, C192A) were non-functional and located mostly in the cell’s interior. The conserved cysteine residues of the V2 Receptor are thus not only important for the structure of the ligand binding domain but also for efficient intracellular Receptor transport. In addition to the functional significance of the conserved cysteine residues, we have also analyzed the defects of two mutant V2 Receptors which cause X-linked nephrogenic diabetes insipidus (NDI) by the introduction of additional cysteine residues into the second extracellular loop (mutants G185C, R202C). These mutations are assumed to impair normal disulfide bond formation. Mutant Receptor G185C and R202C were efficiently transported to the plasma membrane but were defective in ligand binding. Only in the case of the mutant Receptor R202C, the more sensitive adenylyl cyclase activity assay revealed Vasopressin-stimulated cAMP formation with a 35-fold increased EC50 value and with a reduced ECmax, indicating that ligand binding is not completely abolished. Taking the unaffected intracellular transport of both NDI-causing mutant Receptors into account, our results indicate that the observed impairment of ligand binding by the additional cysteine residues is not due to the prevention of disulfide bond formation between the conserved cysteine residues.
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Polarized expression of the Vasopressin V2 Receptor in Madin-Darby canine kidney cells.
Kidney international, 1999Co-Authors: Bettina Andersen-beckh, Marcel Dehe, Ralf Schülein, Burkhard Wiesner, Claudia Rutz, Ursula Liebenhoff, Walter Rosenthal, Alexander OkscheAbstract:Polarized expression of the Vasopressin V2 Receptor in Madin-Darby canine kidney cells. Background The Vasopressin V2 Receptor is expressed in the polarized principal cell of the renal collecting duct. Inactivating mutations of the Vasopressin V2 Receptor gene cause X-linked nephrogenic diabetes insipidus (NDI). Most of the mutant V2 Receptors show transport defects, as analyzed in non-polarized cells, but data pertaining to polarized cells have not previously been presented. Methods Madin-Darby canine kidney cell (MDCK) II clones stably expressing c-myc–tagged human V2 Receptors were characterized for [ 3 H]-arginine Vasopressin (AVP)-binding and AVP-sensitive adenylyl cyclase activity. The V2 Receptors were immunocytochemically localized using the tyramide signal amplification technique in conjunction with an anti–c-myc antibody. Results The introduction of the c-myc epitope at the N- or C-terminus did not affect the functional properties of the V2 Receptor expressed in MDCK II clones. However, the use of standard immunofluorescence methodology for these MDCK II clones yielded only weak signals. With the tyramide signal amplification technique, strong signals were obtained, showing the V2 Receptor to be mainly localized within the lateral and, to a minor extent, apical membrane. In MDCK II clones stably expressing the c-myc–tagged V2 Receptor NDI mutant L44P, fluorescent signals were found exclusively within the cell. Conclusion The wild-type V2 Receptor is expressed mainly in the lateral membrane, whereas the L44P mutant is completely retained within the cell. In conjunction with tyramide signal amplification, MDCK II cells constitute a suitable model for the analysis of transport-defective mutants of the V2 Receptor.
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Polarized cell surface expression of the green fluorescent protein-tagged Vasopressin V2 Receptor in Madin Darby canine kidney cells
FEBS letters, 1998Co-Authors: Ralf Schülein, Burkhard Wiesner, Alexander Oksche, Ricardo Hermosilla, Dorothea Lorenz, Jutta Ebert, Walter RosenthalAbstract:We have analyzed the polarized cell surface expression of the G protein-coupled Vasopressin V2 Receptor (V2 Receptor) in Madin-Darby canine kidney (MDCK) epithelial cells by both conventional cell surface biotinylation assays and laser scanning microscopy of green fluorescent protein (GFP)-tagged Receptors. Cell surface biotinylation assays with stably transfected filter-grown cells expressing alkaline phosphatase (PhoA)-tagged Receptors demonstrated that the V2 Receptor is located predominantly basolaterally at steady state, while minor amounts are expressed apically. Laser scanning microscopy of filter- and glass-grown MDCK cells stably transfected with a GFP-tagged V2 Receptor confirmed that the Receptor is expressed mainly basolaterally; within the basolateral compartment, however, the Receptor was confined to the lateral subdomain. The results obtained with the GFP-tagged Receptor are thus consistent with and refine those from the biotinylation assay, which does not discriminate lateral from basal membrane regions. Our data indicate that the GFP methodology may effectively supplement cell surface biotinylation assays in future studies of polarized Receptor transport. We finally show that microinjection of a plasmid encoding the GFP-tagged V2 Receptor into the nucleus of MDCK cells led to the same results as experiments with stably transfected cells. However, since there was no need for selecting stably transfected cell lines, the experiments were complete within hours. The microinjection technique thus constitutes a powerful single cell technique to study the intracellular transport of G protein-coupled Receptors. The methodology may be applicable to any cell type, even to tissue-derived, primary cultured cells; coinjection of transport-regulating compounds should also be possible.
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Folding and cell surface expression of the Vasopressin V2 Receptor: requirement of the intracellular C‐terminus
FEBS Letters, 1998Co-Authors: Alexander Oksche, Marcel Dehe, Ralf Schülein, Burkhard Wiesner, Walter RosenthalAbstract:We characterized truncations of the human Vasopressin V2 Receptor to determine the role of the intracellular C-terminus (comprising about 44 amino acids) in Receptor function and cell surface expression. In contrast to the wild-type Receptor, the naturally occurring mutant R337X failed to confer specific [3H]AVP binding to transfected cells. In addition, no Vasopressin-sensitive adenylyl cyclase was detectable in membrane preparations of these cells. Laser scanning microscopy revealed that c-myc epitope- or green fluorescent protein-tagged R337X mutant Receptors were retained within the endoplasmic reticulum. Increasing the number of C-terminal residues (truncations after codons 348, 354 and 356) restored G protein coupling, but revealed a length-dependent reduction of cell surface expression. Replacement of positively charged residues within the C-terminus by glutamine residues also decreased cell surface expression. A chimeric V2 Receptor with the C-terminus replaced by that of the β2-adrenergic Receptor did not bind [3H]AVP and was retained within the cell. These data suggest that residues in the N-terminal part of the C-terminus are necessary for correct folding and that C-terminal residues are important for efficient cell surface expression.
Joseph G. Verbalis - One of the best experts on this subject based on the ideXlab platform.
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Sex differences in Vasopressin V2 Receptor expression and Vasopressin-induced antidiuresis
American journal of physiology. Renal physiology, 2010Co-Authors: Jun Liu, Kathryn Sandberg, Nikhil Sharma, Wei Zheng, Helen Tam, Michaele B. Manigrasso, Joseph G. VerbalisAbstract:The renal Vasopressin V2 Receptor (V2R) plays a critical role in physiological and pathophysiological processes associated with arginine Vasopressin (AVP)-induced antidiuresis. Because clinical data suggests that females may be more prone to hyponatremia from AVP-mediated antidiuresis, we investigated whether there are sex differences in the expression and function of the renal V2R. In normal Sprague-Dawley rat kidneys, V2R mRNA and protein expression was 2.6- and 1.7-fold higher, respectively, in females compared with males. To investigate the potential physiological implications of this sex difference, we studied changes in urine osmolality induced by the AVP V2R agonist desmopressin. In response to different doses of desmopressin, there was a graded increase in urine osmolality and decrease in urine volume during a 24-h infusion. Females showed greater mean increases in urine osmolality and greater mean decreases in urine volume at 0.5 and 5.0 ng/h infusion rates. We also studied renal escape from antidiuresis produced by water loading in rats infused with desmopressin (5.0 ng/h). After 5 days of water loading, urine osmolality of both female and male rats escaped to the same degree physiologically, but V2R mRNA and protein in female kidneys was reduced to a greater degree (−63% and −73%, respectively) than in males (−32% and −48%, respectively). By the end of the 5-day escape period, renal V2R mRNA and protein expression were reduced to the same relative levels in males and females, thereby abolishing the sex differences in V2R expression seen in the basal state. Our results demonstrate that female rats express significantly more V2R mRNA and protein in kidneys than males, and that this results physiologically in a greater sensitivity to V2R agonist administration. The potential pathophysiological implications of these results are that females may be more susceptible to the development of dilutional hyponatremia because of a greater sensitivity to endogenously secreted AVP.
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Vasopressin V2 Receptor antagonists.
Journal of molecular endocrinology, 2002Co-Authors: Joseph G. VerbalisAbstract:Hyponatremia, whether due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH) or disorders of water retention such as congestive heart failure and cirrhosis, is a very common problem encountered in the care of medical patients. To date, available treatment modalities for disorders of excess arginine Vasopressin (AVP) secretion or action have been limited and suboptimal. The recent discovery and development of nonpeptide AVP V(2) Receptor antagonists represents a promising new treatment option to directly antagonize the effects of elevated plasma AVP concentrations at the level of the renal collecting ducts. By decreasing the water permeability of renal collecting tubules, excretion of retained water is promoted, thereby normalizing or improving hypo-osmolar hyponatremia. In this review, SIADH and other water retaining disorders are briefly discussed, after which the published preclinical and clinical studies of several nonpeptide AVP V(2) Receptor antagonists are summarized. The likely therapeutic indications and potential complications of these compounds are also described.
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Vasopressin V2 Receptor antagonists.
Cardiovascular research, 2001Co-Authors: Lisa L. Wong, Joseph G. VerbalisAbstract:Hyponatremia due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and disorders of water retention such as congestive heart failure and cirrhosis is a common problem encountered in the care of the medical patient. Thus far, available treatment modalities for disorders of excess arginine Vasopressin (AVP) secretion or action have been suboptimal. The development of nonpeptide AVP V2 Receptor antagonists represents a promising treatment option to directly antgonize the effects of elevated plasma AVP concentrations by increasing the water permeability of renal collecting tubules, thereby promoting excretion of retained water and normalizing hypoosmolar hyponatremia. In this review, SIADH and other water retaining disorders are briefly discussed, after which the published preclinical and clinical studies in the development of several nonpeptide AVP V2 Receptor antagonists are summarized. The likely therapeutic indications and potential complications of these compounds, as well as their vascular effects, are also described.
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Vasopressin V2 Receptor Binding Is Down-Regulated during Renal Escape from Vasopressin-Induced Antidiuresis1
Endocrinology, 2000Co-Authors: Ying Tian, Kathryn Sandberg, Takashi Murase, Erin A. Baker, Robert C. Speth, Joseph G. VerbalisAbstract:This study evaluated whether renal escape from Vasopressin-induced antidiuresis is associated with alterations of Vasopressin V2 Receptor binding in the kidney inner medulla. A radioligand binding assay was developed using a novel iodinated Vasopressin V2 Receptor antagonist to analyze Vasopressin V2 Receptor binding in kidney inner medullary tissue from three groups of rats: normal rats maintained on ad libitum water intake, rats treated with 1-deamino-[8-d-arginine]Vasopressin (DDAVP), and rats treated with DDAVP that were also water loaded to induce renal escape from antidiuresis. Analysis of the binding data showed that DDAVP treatment reduced Vasopressin V2 Receptor binding to 72% of normal levels. Water loading induced a marked further down-regulation of Vasopressin V2 Receptor binding. This Receptor down-regulation began by day 2 of water loading, which correlated with the initiation of renal Vasopressin escape; by day 3 of water loading, Vasopressin V2 Receptor expression fell to 43% of DDAVP-trea...
Vicente E Torres - One of the best experts on this subject based on the ideXlab platform.
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effect of a Vasopressin V2 Receptor antagonist on polycystic kidney disease development in a rat model
American Journal of Nephrology, 2019Co-Authors: Xiaofang Wang, Vicente E Torres, Megan M Constans, Fouad T Chebib, Lorenzo PellegriniAbstract:Background: Vasopressin V2 Receptor inhibition is a clinically validated mechanism of action in the treatment of autosomal dominant polycystic kidney disease (ADPKD). In this study, the effect of lixivaptan, a potent, selective Vasopressin V2 antagonist, was evaluated in PCK rats, a validated animal model of PKD. Methods: Four-week old PCK rats were fed rodent chow with 0.5% lixivaptan (low dose) or 1% lixivaptan (high dose), or chow only (control) for 8 weeks. Urine output was measured at weeks 7 and 10 of age. Animals were killed at 12 weeks of age; kidneys and livers were collected, weighted, and analyzed for cyclic adenosine 3′,5′-monophosphate (cAMP) levels and cystic burden and fibrosis; serum creatinine and sodium were measured. Results: Consistent with the development of a polycystic kidney phenotype, control PCK rats showed enlarged kidneys, extensive cyst formation, and early signs of serum creatinine elevation at 12 weeks of age. Compared to controls, PCK rats treated with low-dose lixivaptan showed a 26% reduction in % kidney weight/body weight (p < 0.01); a 54% reduction in kidney cystic score (p < 0.001), a histomorphometric measure of cystic burden; a 23% reduction in kidney cAMP levels (p < 0.05), a biochemical marker of disease; and a 13% reduction in plasma creatinine (p < 0.001), indicating preserved renal function. These reductions were associated with 3-fold increases in 24-h urine output, demonstrating the potent aquaretic effect of lixivaptan. The fact that the high dose was less efficacious than the low dose is discussed. Conclusions: These results provide the first evidence of the potential utility of lixivaptan for the treatment of ADPKD.
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polyuria due to Vasopressin V2 Receptor antagonism is not associated with increased ureter diameter in adpkd patients
Clinical and Experimental Nephrology, 2017Co-Authors: Niek F Casteleijn, Lianne A Messchendorp, Peter Kappert, Esther Meijer, Eiji Higashihara, Vicente E Torres, Anna M LeliveldAbstract:Background Tolvaptan, a Vasopressin V2 Receptor antagonist, has been shown to reduce the rates of growth in total kidney volume (TKV) and renal function loss in ADPKD patients, but also leads to polyuria because of its aquaretic effect. Prolonged polyuria can result in ureter dilatation with consequently renal function loss. Therefore, we aimed to investigate the effect of tolvaptan-induced polyuria on ureter diameter in ADPKD patients.
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rationale and design of a clinical trial investigating tolvaptan safety and efficacy in autosomal dominant polycystic kidney disease
American Journal of Nephrology, 2017Co-Authors: Vicente E Torres, Ron T. Gansevoort, John Ouyang, Frank S. Czerwiec, Olivier Devuyst, Arlene B Chapman, Ronald D Perrone, Jaime D Blais, Olga SergeyevaAbstract:Background: In TEMPO 3:4, the Vasopressin V2-Receptor antagonist tolvaptan slowed kidney growth and function decline in autosomal dominant polycystic kidney disea
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effectiveness of Vasopressin V2 Receptor antagonists opc 31260 and opc 41061 on polycystic kidney disease development in the pck rat
Journal of The American Society of Nephrology, 2005Co-Authors: Xiaofang Wang, Vincent H Gattone, Peter C. Harris, Vicente E TorresAbstract:cAMP plays a major role in cystogenesis. Recent in vitro studies suggested that cAMP stimulates B-Raf/ERK activation and proliferation of cyst-derived cells in a Ca 2+ inhibitable, Ras-dependent manner. OPC-31260, a Vasopressin V2 Receptor (VPV2) antagonist, was shown to lower renal cAMP and inhibit renal disease development and progression in models orthologous to human cystic diseases. Here it is shown that OPC-41061, an antagonist chosen for its potency and selectivity for human VPV2, is effective in PCK rats. PCK kidneys have increased Ras-GTP and phosphorylated ERK levels and 95-kD/68-kD B-Raf ratios, changes that are corrected by the administration of OPC-31260 or OPC-41061. These results support the importance of cAMP in the pathogenesis of polycystic kidney disease, confirm the effectiveness of a VPV2 antagonist to be used in clinical trials for this disease, and suggest that OPC-31260 and OPC-41061 inhibit Ras/mitogen-activated protein kinase signaling in polycystic kidneys.
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inhibition of renal cystic disease development and progression by a Vasopressin V2 Receptor antagonist
Nature Medicine, 2003Co-Authors: Vincent H Gattone, Peter C. Harris, Xiaofang Wang, Vicente E TorresAbstract:Inhibition of renal cystic disease development and progression by a Vasopressin V2 Receptor antagonist