The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
Wolfgang Meyerhof - One of the best experts on this subject based on the ideXlab platform.
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intracellular degradation of Somatostatin 14 following Somatostatin Receptor 3 mediated endocytosis in rat insulinoma cells
FEBS Journal, 2008Co-Authors: Dirk Roosterman, Nicole E I Brune, Oliver J Kreuzer, Micha Feld, Sylvia Pauser, Kim Zarse, Martin Steinhoff, Wolfgang MeyerhofAbstract:Somatostatin Receptor (SSTR) endocytosis influences cellular responsiveness to agonist stimulation and Somatostatin Receptor scintigraphy, a common diagnostic imaging technique. Recently, we have shown that SSTR1 is differentially regulated in the endocytic and recycling pathway of pancreatic cells after agonist stimulation. Additionally, SSTR1 accumulates and releases internalized Somatostatin-14 (SST-14) as an intact and biologically active ligand. We also demonstrated that SSTR2A was sequestered into early endosomes, whereas internalized SST-14 was degraded by endosomal peptidases and not routed into lysosomal degradation. Here, we examined the fate of peptide agonists in rat insulinoma cells expressing SSTR3 by biochemical methods and confocal laser scanning microscopy. We found that [125I]Tyr11-SST-14 rapidly accumulated in intracellular vesicles, where it was degraded in an ammonium chloride-sensitive manner. In contrast, [125I]Tyr1-octreotide accumulated and was released as an intact peptide. Rhodamine-B-labeled SST-14, however, was rapidly internalized into endosome-like vesicles, and fluorescence signals colocalized with the lysosomal marker protein cathepsin D. Our data show that SST-14 was cointernalized with SSTR3, was uncoupled from the Receptor, and was sorted into an endocytic degradation pathway, whereas octreotide was recycled as an intact peptide. Chronic stimulation of SSTR3 also induced time-dependent downregulation of the Receptor. Thus, the intracellular processing of internalized SST-14 and the regulation of SSTR3 markedly differ from the events mediated by the other SSTR subtypes.
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Intracellular degradation of Somatostatin‐14 following Somatostatin‐Receptor 3‐mediated endocytosis in rat insulinoma cells
The FEBS journal, 2008Co-Authors: Dirk Roosterman, Nicole E I Brune, Oliver J Kreuzer, Micha Feld, Sylvia Pauser, Kim Zarse, Martin Steinhoff, Wolfgang MeyerhofAbstract:Somatostatin Receptor (SSTR) endocytosis influences cellular responsiveness to agonist stimulation and Somatostatin Receptor scintigraphy, a common diagnostic imaging technique. Recently, we have shown that SSTR1 is differentially regulated in the endocytic and recycling pathway of pancreatic cells after agonist stimulation. Additionally, SSTR1 accumulates and releases internalized Somatostatin-14 (SST-14) as an intact and biologically active ligand. We also demonstrated that SSTR2A was sequestered into early endosomes, whereas internalized SST-14 was degraded by endosomal peptidases and not routed into lysosomal degradation. Here, we examined the fate of peptide agonists in rat insulinoma cells expressing SSTR3 by biochemical methods and confocal laser scanning microscopy. We found that [125I]Tyr11-SST-14 rapidly accumulated in intracellular vesicles, where it was degraded in an ammonium chloride-sensitive manner. In contrast, [125I]Tyr1-octreotide accumulated and was released as an intact peptide. Rhodamine-B-labeled SST-14, however, was rapidly internalized into endosome-like vesicles, and fluorescence signals colocalized with the lysosomal marker protein cathepsin D. Our data show that SST-14 was cointernalized with SSTR3, was uncoupled from the Receptor, and was sorted into an endocytic degradation pathway, whereas octreotide was recycled as an intact peptide. Chronic stimulation of SSTR3 also induced time-dependent downregulation of the Receptor. Thus, the intracellular processing of internalized SST-14 and the regulation of SSTR3 markedly differ from the events mediated by the other SSTR subtypes.
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Expression patterns of rat Somatostatin Receptor genes in pre- and postnatal brain and pituitary.
Journal of neurochemistry, 1993Co-Authors: Irk Wulfsen, Wolfgang Meyerhof, Susanne Fehr, Dietmar RichterAbstract:The relative abundances of mRNAs encoding four different Somatostatin Receptors were examined using PCR techniques during postnatal development of the rat brain and hypophysis. In most tissues, Somatostatin Receptor 1 and 4 mRNAs are more abundant than those encoding Somatostatin Receptor 2 and 3. Transcript levels of Somatostatin Receptor subtype 4 are relatively high in the cortex, hippocampus, and striatum, those of subtype 1 in the cortex and brainstem, and those of subtype 3 in the cerebellum. In situ hybridization revealed the presence of significant amounts of Somatostatin Receptor 1 mRNA, as early as prenatal day 14, in the trigeminal ganglion and in the neuroepithelial layers surrounding the lateral, third, and fourth ventricles. In the developing cortex a morphological change in the sites of Somatostatin Receptor 1 gene expression occurs; mRNA is present superficially in the cortex at prenatal stages, appears in all layers shortly after birth, and in adult rats is restricted to the deep cortical layers. In the cerebellum, Somatostatin Receptor 1 mRNA levels are highest around birth, declining thereafter. In contrast, cerebellar Somatostatin Receptor 3 transcripts are absent at birth, become detectable around postnatal day 7, and reach a maximal level during maturation.
Maxence V Nachury - One of the best experts on this subject based on the ideXlab platform.
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Ubiquitin chains earmark GPCRs for BBSome-mediated removal from cilia.
The Journal of cell biology, 2020Co-Authors: Swapnil Rohidas Shinde, Andrew R Nager, Maxence V NachuryAbstract:Regulated trafficking of G protein-coupled Receptors (GPCRs) controls cilium-based signaling pathways. β-Arrestin, a molecular sensor of activated GPCRs, and the BBSome, a complex of Bardet-Biedl syndrome (BBS) proteins, are required for the signal-dependent exit of ciliary GPCRs, but the functional interplay between β-arrestin and the BBSome remains elusive. Here we find that, upon activation, ciliary GPCRs become tagged with ubiquitin chains comprising K63 linkages (UbK63) in a β-arrestin-dependent manner before BBSome-mediated exit. Removal of ubiquitin acceptor residues from the Somatostatin Receptor 3 (SSTR3) and from the orphan GPCR GPR161 demonstrates that ubiquitination of ciliary GPCRs is required for their regulated exit from cilia. Furthermore, targeting a UbK63-specific deubiquitinase to cilia blocks the exit of GPR161, SSTR3, and Smoothened (SMO) from cilia. Finally, ubiquitinated proteins accumulate in cilia of mammalian photoReceptors and Chlamydomonas cells when BBSome function is compromised. We conclude that Ub chains mark GPCRs and other unwanted ciliary proteins for recognition by the ciliary exit machinery.
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Lysine63-linked ubiquitin chains earmark GPCRs for BBSome-mediated removal from cilia
2020Co-Authors: Swapnil Rohidas Shinde, Andrew R Nager, Maxence V NachuryAbstract:Author(s): Shinde, Swapnil Rohidas; Nager, Andrew; Nachury, Maxence | Abstract: ABSTRACT Regulated trafficking of G-protein coupled Receptors (GPCRs) controls cilium-based signaling pathways. β-arrestin, a molecular sensor of activated GPCRs, and the BBSome, a complex of Bardet-Biedl Syndrome (BBS) proteins, are required for the signal-dependent exit of ciliary GPCRs but the functional interplay between β-arrestin and the BBSome remains elusive. Here we find that, upon activation, ciliary GPCRs become tagged with K63-linked ubiquitin (K63Ub) chains in a β-arrestin-dependent manner prior to BBSome-mediated exit. Removal of ubiquitin acceptor residues from the Somatostatin Receptor 3 (SSTR3) and from the orphan GPCR GPR161 demonstrates that ubiquitination of ciliary GPCRs is required for their regulated exit from cilia. Furthermore, targeting a K63Ub-specific deubiquitinase to cilia blocks the exit of GPR161, SSTR3 and Smoothened (SMO) from cilia. Finally, ubiquitinated proteins accumulate in cilia of mammalian photoReceptors and Chlamydomonas cells when BBSome function is compromised. We conclude that K63Ub chains mark GPCRs and other unwanted ciliary proteins for recognition by the ciliary exit machinery.
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single molecule imaging reveals a major role for diffusion in the exploration of ciliary space by signaling Receptors
eLife, 2013Co-Authors: Fan Ye, David K Breslow, Elena F Koslover, Andrew J Spakowitz, James W Nelson, Maxence V NachuryAbstract:The dynamic organization of signaling cascades inside primary cilia is key to signal propagation. Yet little is known about the dynamics of ciliary membrane proteins besides a possible role for motor-driven Intraflagellar Transport (IFT). To characterize these dynamics, we imaged single molecules of Somatostatin Receptor 3 (SSTR3, a GPCR) and Smoothened (Smo, a Hedgehog signal transducer) in the ciliary membrane. While IFT trains moved processively from one end of the cilium to the other, single SSTR3 and Smo underwent mostly diffusive behavior interspersed with short periods of directional movements. Statistical subtraction of instant velocities revealed that SSTR3 and Smo spent less than a third of their time undergoing active transport. Finally, SSTR3 and IFT movements could be uncoupled by perturbing either membrane protein diffusion or active transport. Thus ciliary membrane proteins move predominantly by diffusion, and attachment to IFT trains is transient and stochastic rather than processive or spatially determined. DOI: http://dx.doi.org/10.7554/eLife.00654.001
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the conserved bardet biedl syndrome proteins assemble a coat that traffics membrane proteins to cilia
Cell, 2010Co-Authors: Hua Jin, Stefan Schulz, Susan Roehl White, Toshinobu Shida, Mike Aguiar, Steven P Gygi, Fernando J Bazan, Maxence V NachuryAbstract:Summary The BBSome is a complex of Bardet-Biedl Syndrome (BBS) proteins that shares common structural elements with COPI, COPII, and clathrin coats. Here, we show that the BBSome constitutes a coat complex that sorts membrane proteins to primary cilia. The BBSome is the major effector of the Arf-like GTPase Arl6/BBS3, and the BBSome and GTP-bound Arl6 colocalize at ciliary punctae in an interdependent manner. Strikingly, Arl6 GTP -mediated recruitment of the BBSome to synthetic liposomes produces distinct patches of polymerized coat apposed onto the lipid bilayer. Finally, the ciliary targeting signal of Somatostatin Receptor 3 needs to be directly recognized by the BBSome in order to mediate targeting of membrane proteins to cilia. Thus, we propose that trafficking of BBSome cargoes to cilia entails the coupling of BBSome coat polymerization to the recognition of sorting signals by the BBSome.
Dirk Roosterman - One of the best experts on this subject based on the ideXlab platform.
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intracellular degradation of Somatostatin 14 following Somatostatin Receptor 3 mediated endocytosis in rat insulinoma cells
FEBS Journal, 2008Co-Authors: Dirk Roosterman, Nicole E I Brune, Oliver J Kreuzer, Micha Feld, Sylvia Pauser, Kim Zarse, Martin Steinhoff, Wolfgang MeyerhofAbstract:Somatostatin Receptor (SSTR) endocytosis influences cellular responsiveness to agonist stimulation and Somatostatin Receptor scintigraphy, a common diagnostic imaging technique. Recently, we have shown that SSTR1 is differentially regulated in the endocytic and recycling pathway of pancreatic cells after agonist stimulation. Additionally, SSTR1 accumulates and releases internalized Somatostatin-14 (SST-14) as an intact and biologically active ligand. We also demonstrated that SSTR2A was sequestered into early endosomes, whereas internalized SST-14 was degraded by endosomal peptidases and not routed into lysosomal degradation. Here, we examined the fate of peptide agonists in rat insulinoma cells expressing SSTR3 by biochemical methods and confocal laser scanning microscopy. We found that [125I]Tyr11-SST-14 rapidly accumulated in intracellular vesicles, where it was degraded in an ammonium chloride-sensitive manner. In contrast, [125I]Tyr1-octreotide accumulated and was released as an intact peptide. Rhodamine-B-labeled SST-14, however, was rapidly internalized into endosome-like vesicles, and fluorescence signals colocalized with the lysosomal marker protein cathepsin D. Our data show that SST-14 was cointernalized with SSTR3, was uncoupled from the Receptor, and was sorted into an endocytic degradation pathway, whereas octreotide was recycled as an intact peptide. Chronic stimulation of SSTR3 also induced time-dependent downregulation of the Receptor. Thus, the intracellular processing of internalized SST-14 and the regulation of SSTR3 markedly differ from the events mediated by the other SSTR subtypes.
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Intracellular degradation of Somatostatin‐14 following Somatostatin‐Receptor 3‐mediated endocytosis in rat insulinoma cells
The FEBS journal, 2008Co-Authors: Dirk Roosterman, Nicole E I Brune, Oliver J Kreuzer, Micha Feld, Sylvia Pauser, Kim Zarse, Martin Steinhoff, Wolfgang MeyerhofAbstract:Somatostatin Receptor (SSTR) endocytosis influences cellular responsiveness to agonist stimulation and Somatostatin Receptor scintigraphy, a common diagnostic imaging technique. Recently, we have shown that SSTR1 is differentially regulated in the endocytic and recycling pathway of pancreatic cells after agonist stimulation. Additionally, SSTR1 accumulates and releases internalized Somatostatin-14 (SST-14) as an intact and biologically active ligand. We also demonstrated that SSTR2A was sequestered into early endosomes, whereas internalized SST-14 was degraded by endosomal peptidases and not routed into lysosomal degradation. Here, we examined the fate of peptide agonists in rat insulinoma cells expressing SSTR3 by biochemical methods and confocal laser scanning microscopy. We found that [125I]Tyr11-SST-14 rapidly accumulated in intracellular vesicles, where it was degraded in an ammonium chloride-sensitive manner. In contrast, [125I]Tyr1-octreotide accumulated and was released as an intact peptide. Rhodamine-B-labeled SST-14, however, was rapidly internalized into endosome-like vesicles, and fluorescence signals colocalized with the lysosomal marker protein cathepsin D. Our data show that SST-14 was cointernalized with SSTR3, was uncoupled from the Receptor, and was sorted into an endocytic degradation pathway, whereas octreotide was recycled as an intact peptide. Chronic stimulation of SSTR3 also induced time-dependent downregulation of the Receptor. Thus, the intracellular processing of internalized SST-14 and the regulation of SSTR3 markedly differ from the events mediated by the other SSTR subtypes.
Nicole E I Brune - One of the best experts on this subject based on the ideXlab platform.
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intracellular degradation of Somatostatin 14 following Somatostatin Receptor 3 mediated endocytosis in rat insulinoma cells
FEBS Journal, 2008Co-Authors: Dirk Roosterman, Nicole E I Brune, Oliver J Kreuzer, Micha Feld, Sylvia Pauser, Kim Zarse, Martin Steinhoff, Wolfgang MeyerhofAbstract:Somatostatin Receptor (SSTR) endocytosis influences cellular responsiveness to agonist stimulation and Somatostatin Receptor scintigraphy, a common diagnostic imaging technique. Recently, we have shown that SSTR1 is differentially regulated in the endocytic and recycling pathway of pancreatic cells after agonist stimulation. Additionally, SSTR1 accumulates and releases internalized Somatostatin-14 (SST-14) as an intact and biologically active ligand. We also demonstrated that SSTR2A was sequestered into early endosomes, whereas internalized SST-14 was degraded by endosomal peptidases and not routed into lysosomal degradation. Here, we examined the fate of peptide agonists in rat insulinoma cells expressing SSTR3 by biochemical methods and confocal laser scanning microscopy. We found that [125I]Tyr11-SST-14 rapidly accumulated in intracellular vesicles, where it was degraded in an ammonium chloride-sensitive manner. In contrast, [125I]Tyr1-octreotide accumulated and was released as an intact peptide. Rhodamine-B-labeled SST-14, however, was rapidly internalized into endosome-like vesicles, and fluorescence signals colocalized with the lysosomal marker protein cathepsin D. Our data show that SST-14 was cointernalized with SSTR3, was uncoupled from the Receptor, and was sorted into an endocytic degradation pathway, whereas octreotide was recycled as an intact peptide. Chronic stimulation of SSTR3 also induced time-dependent downregulation of the Receptor. Thus, the intracellular processing of internalized SST-14 and the regulation of SSTR3 markedly differ from the events mediated by the other SSTR subtypes.
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Intracellular degradation of Somatostatin‐14 following Somatostatin‐Receptor 3‐mediated endocytosis in rat insulinoma cells
The FEBS journal, 2008Co-Authors: Dirk Roosterman, Nicole E I Brune, Oliver J Kreuzer, Micha Feld, Sylvia Pauser, Kim Zarse, Martin Steinhoff, Wolfgang MeyerhofAbstract:Somatostatin Receptor (SSTR) endocytosis influences cellular responsiveness to agonist stimulation and Somatostatin Receptor scintigraphy, a common diagnostic imaging technique. Recently, we have shown that SSTR1 is differentially regulated in the endocytic and recycling pathway of pancreatic cells after agonist stimulation. Additionally, SSTR1 accumulates and releases internalized Somatostatin-14 (SST-14) as an intact and biologically active ligand. We also demonstrated that SSTR2A was sequestered into early endosomes, whereas internalized SST-14 was degraded by endosomal peptidases and not routed into lysosomal degradation. Here, we examined the fate of peptide agonists in rat insulinoma cells expressing SSTR3 by biochemical methods and confocal laser scanning microscopy. We found that [125I]Tyr11-SST-14 rapidly accumulated in intracellular vesicles, where it was degraded in an ammonium chloride-sensitive manner. In contrast, [125I]Tyr1-octreotide accumulated and was released as an intact peptide. Rhodamine-B-labeled SST-14, however, was rapidly internalized into endosome-like vesicles, and fluorescence signals colocalized with the lysosomal marker protein cathepsin D. Our data show that SST-14 was cointernalized with SSTR3, was uncoupled from the Receptor, and was sorted into an endocytic degradation pathway, whereas octreotide was recycled as an intact peptide. Chronic stimulation of SSTR3 also induced time-dependent downregulation of the Receptor. Thus, the intracellular processing of internalized SST-14 and the regulation of SSTR3 markedly differ from the events mediated by the other SSTR subtypes.
Oliver J Kreuzer - One of the best experts on this subject based on the ideXlab platform.
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intracellular degradation of Somatostatin 14 following Somatostatin Receptor 3 mediated endocytosis in rat insulinoma cells
FEBS Journal, 2008Co-Authors: Dirk Roosterman, Nicole E I Brune, Oliver J Kreuzer, Micha Feld, Sylvia Pauser, Kim Zarse, Martin Steinhoff, Wolfgang MeyerhofAbstract:Somatostatin Receptor (SSTR) endocytosis influences cellular responsiveness to agonist stimulation and Somatostatin Receptor scintigraphy, a common diagnostic imaging technique. Recently, we have shown that SSTR1 is differentially regulated in the endocytic and recycling pathway of pancreatic cells after agonist stimulation. Additionally, SSTR1 accumulates and releases internalized Somatostatin-14 (SST-14) as an intact and biologically active ligand. We also demonstrated that SSTR2A was sequestered into early endosomes, whereas internalized SST-14 was degraded by endosomal peptidases and not routed into lysosomal degradation. Here, we examined the fate of peptide agonists in rat insulinoma cells expressing SSTR3 by biochemical methods and confocal laser scanning microscopy. We found that [125I]Tyr11-SST-14 rapidly accumulated in intracellular vesicles, where it was degraded in an ammonium chloride-sensitive manner. In contrast, [125I]Tyr1-octreotide accumulated and was released as an intact peptide. Rhodamine-B-labeled SST-14, however, was rapidly internalized into endosome-like vesicles, and fluorescence signals colocalized with the lysosomal marker protein cathepsin D. Our data show that SST-14 was cointernalized with SSTR3, was uncoupled from the Receptor, and was sorted into an endocytic degradation pathway, whereas octreotide was recycled as an intact peptide. Chronic stimulation of SSTR3 also induced time-dependent downregulation of the Receptor. Thus, the intracellular processing of internalized SST-14 and the regulation of SSTR3 markedly differ from the events mediated by the other SSTR subtypes.
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Intracellular degradation of Somatostatin‐14 following Somatostatin‐Receptor 3‐mediated endocytosis in rat insulinoma cells
The FEBS journal, 2008Co-Authors: Dirk Roosterman, Nicole E I Brune, Oliver J Kreuzer, Micha Feld, Sylvia Pauser, Kim Zarse, Martin Steinhoff, Wolfgang MeyerhofAbstract:Somatostatin Receptor (SSTR) endocytosis influences cellular responsiveness to agonist stimulation and Somatostatin Receptor scintigraphy, a common diagnostic imaging technique. Recently, we have shown that SSTR1 is differentially regulated in the endocytic and recycling pathway of pancreatic cells after agonist stimulation. Additionally, SSTR1 accumulates and releases internalized Somatostatin-14 (SST-14) as an intact and biologically active ligand. We also demonstrated that SSTR2A was sequestered into early endosomes, whereas internalized SST-14 was degraded by endosomal peptidases and not routed into lysosomal degradation. Here, we examined the fate of peptide agonists in rat insulinoma cells expressing SSTR3 by biochemical methods and confocal laser scanning microscopy. We found that [125I]Tyr11-SST-14 rapidly accumulated in intracellular vesicles, where it was degraded in an ammonium chloride-sensitive manner. In contrast, [125I]Tyr1-octreotide accumulated and was released as an intact peptide. Rhodamine-B-labeled SST-14, however, was rapidly internalized into endosome-like vesicles, and fluorescence signals colocalized with the lysosomal marker protein cathepsin D. Our data show that SST-14 was cointernalized with SSTR3, was uncoupled from the Receptor, and was sorted into an endocytic degradation pathway, whereas octreotide was recycled as an intact peptide. Chronic stimulation of SSTR3 also induced time-dependent downregulation of the Receptor. Thus, the intracellular processing of internalized SST-14 and the regulation of SSTR3 markedly differ from the events mediated by the other SSTR subtypes.