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Mauro Pessia - One of the best experts on this subject based on the ideXlab platform.
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Role of Receptor Protein tyrosine phosphatase alpha (RPTPalpha) and tyrosine phosphorylation in the serotonergic inhibition of voltage-dependent potassium channels.
Pfl�gers Archiv European Journal of Physiology, 2000Co-Authors: Paola Imbrici, Stephen J. Tucker, Maria Cristina D'adamo, Mauro PessiaAbstract:The activity of voltage-gated potassium (Kv) channels can be dynamically modulated by several events, including neurotransmitter-stimulated biochemical cascades mediated by G-Protein-coupled Receptors. By using a heterologous expression system, we show that activating the 5-HT2C Receptor inhibits both Kv1.1 and Kv1.2 channels through a tyrosine phosphorylation mechanism. The major molecular determinants of channel inhibition were identified as two tyrosine residues located in the N-terminal region of the Kv channel subunit. Furthermore, we demonstrate that Receptor Protein tyrosine phosphatase alpha (RPTPalpha), a Receptor Protein tyrosine phosphatase, co-ordinates the inhibition process mediated via 5-HT2C Receptors. We therefore propose that the serotonergic regulation of human Kv1.1 and Kv1.2 channel activity by the 5-HT2C Receptor involves the dual coordination of both RPTPalpha and specific tyrosine kinases coupled to this Receptor.
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Role of Receptor Protein tyrosine phosphatase α (RPTPα) and tyrosine phosphorylation in the serotonergic inhibition of voltage-dependent potassium channels
Pflügers Archiv: European Journal of Physiology, 2000Co-Authors: Paola Imbrici, Stephen J. Tucker, Maria Cristina D'adamo, Mauro PessiaAbstract:The activity of voltage-gated potassium (Kv) channels can be dynamically modulated by several events, including neurotransmitter-stimulated biochemical cascades mediated by G-Protein-coupled Receptors. By using a heterologous expression system, we show that activating the 5-HT2C Receptor inhibits both Kv1.1 and Kv1.2 channels through a tyrosine phosphorylation mechanism. The major molecular determinants of channel inhibition were identified as two tyrosine residues located in the N-terminal region of the Kv channel subunit. Furthermore, we demonstrate that Receptor Protein tyrosine phosphatase α (RPTPα), a Receptor Protein tyrosine phosphatase, co-ordinates the inhibition process mediated via 5-HT2C Receptors. We therefore propose that the serotonergic regulation of human Kv1.1 and Kv1.2 channel activity by the 5-HT2C Receptor involves the dual co-ordination of both RPTPα and specific tyrosine kinases coupled to this Receptor.
Jeroen Den Hertog - One of the best experts on this subject based on the ideXlab platform.
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Receptor Protein tyrosine phosphatases
Protein Phosphatases, 2003Co-Authors: Jeroen Den HertogAbstract:The Receptor Protein-tyrosine phosphatases (RPTPs) form a subfamily of the classical Protein-tyrosine phosphatases (PTPs). RPTPs are interesting because they have the ability to signal across the cell membrane due to their topology. Evidence is accumulating that RPTPs play important roles during embryonic development and in human disease. In addition, our insight into RPTP signalling is growing by identification of specific substrates and ligands. Finally, dimerization is emerging as an important regulatory mechanism of RPTPs and RPTPs may be regulated by redox signalling in an unexpected way.
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Receptor Protein-tyrosine phosphatase dimerization.
Methods in enzymology, 2003Co-Authors: Jeroen Den Hertog, Leon Gj Tertoolen, Thea Van Der Wijk, Christophe BlanchetotAbstract:Publisher Summary This chapter discusses that the Receptor Protein-tyrosine phosphatases (RPTPs) form a subfamily of the classical Protein-tyrosine phosphatase family. It is established that the enzymatic counterparts of the RPTPs, the Receptor Protein-tyrosine kinases (RPTKs), are regulated by ligand binding to their extracellular domain, for example, epidermal growth factor (EGF) binding activates intrinsic PTK activity of the EGF Receptor (EGFR). Similarly, ligand binding to the ectodomain of RPTPs may be involved in regulation of their activity. Dimerization is a well-known regulatory mechanism for single membrane-spanning Receptors. For instance, ligand-induced RPTK activation involves dimerization. The RPTPs may be regulated by dimerization as well. This chapter describes four different techniques that we have used to analyze RPTP dimerization in living cells, namely, (1) chemical cross-linking, (2) genetic crosslinking by introduction of disulfide bonds, (3) fluorescence resonance energy transfer (FRET), and (4) analysis of interactions of RPTP fragments by coimmunoprecipitation. The use of FRET to analyze RPTP dimerization is appealing because it is a noninvasive technique that can be done on living cells and it may eventually be used to detect changes in dimerization in real time in response to stimuli.
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Dimerization of Receptor Protein-tyrosine phosphatase alpha in living cells.
BMC cell biology, 2001Co-Authors: Leon Gj Tertoolen, Christophe Blanchetot, Guoqiang Jiang, John Overvoorde, T.w.j. Gadella, Tony Hunter, Jeroen Den HertogAbstract:Background Dimerization is an important regulatory mechanism of single membrane-spanning Receptors. For instance, activation of Receptor Protein-tyrosine kinases (RPTKs) involves dimerization. Structural, functional and biochemical studies suggested that the enzymatic counterparts of RPTKs, the Receptor Protein-tyrosine phosphatases (RPTPs), are inhibited by dimerization, but whether RPTPs actually dimerize in living cells remained to be determined.
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Dimerization of Receptor Protein-Tyrosine Phosphatase alpha in living cells
BMC Cell Biology, 2001Co-Authors: Leon Gj Tertoolen, Christophe Blanchetot, Guoqiang Jiang, John Overvoorde, T.w.j. Gadella, Tony Hunter, Jeroen Den HertogAbstract:Background Dimerization is an important regulatory mechanism of single membrane-spanning Receptors. For instance, activation of Receptor Protein-tyrosine kinases (RPTKs) involves dimerization. Structural, functional and biochemical studies suggested that the enzymatic counterparts of RPTKs, the Receptor Protein-tyrosine phosphatases (RPTPs), are inhibited by dimerization, but whether RPTPs actually dimerize in living cells remained to be determined. Results In order to assess RPTP dimerization, we have assayed Fluorescence Resonance Energy Transfer (FRET) between chimeric Proteins of cyan- and yellow-emitting derivatives of green fluorescent Protein, fused to RPTPα, using three different techniques: dual wavelength excitation, spectral imaging and fluorescence lifetime imaging. All three techniques suggested that FRET occurred between RPTPα -CFP and -YFP fusion Proteins, and thus that RPTPα dimerized in living cells. RPTPα dimerization was constitutive, extensive and specific. RPTPα dimerization was consistent with cross-linking experiments, using a non-cell-permeable chemical cross-linker. Using a panel of deletion mutants, we found that the transmembrane domain was required and sufficient for dimerization. Conclusions We demonstrate here that RPTPα dimerized constitutively in living cells, which may be mediated by the transmembrane domain, providing strong support for the model that dimerization is involved in regulation of RPTPs.
Andrew W Stoker - One of the best experts on this subject based on the ideXlab platform.
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Cell surface nucleolin on developing muscle is a potential ligand for the axonal Receptor Protein tyrosine phosphatase-sigma.
FEBS Journal, 2006Co-Authors: Daniel E Alete, Mark E Weeks, Ara G Hovanession, Muhamed Hawadle, Andrew W StokerAbstract:Reversible tyrosine phosphorylation, catalyzed by Receptor tyrosine kinases and Receptor tyrosine phosphatases, plays an essential part in cell signaling during axonal development. Receptor Protein tyrosine phosphatase-sigma has been implicated in the growth, guidance and repair of retinal axons. This phosphatase has also been implicated in motor axon growth and innervation. Insect orthologs of Receptor Protein tyrosine phosphatase-sigma are also implicated in the recognition of muscle target cells. A potential extracellular ligand for vertebrate Receptor Protein tyrosine phosphatase-sigma has been previously localized in developing skeletal muscle. The identity of this muscle ligand is currently unknown, but it appears to be unrelated to the heparan sulfate ligands of Receptor Protein tyrosine phosphatase-sigma. In this study, we have used affinity chromatography and tandem MS to identify nucleolin as a binding partner for Receptor Protein tyrosine phosphatase-sigma in skeletal muscle tissue. Nucleolin, both from tissue lysates and in purified form, binds to Receptor Protein tyrosine phosphatase-sigma ectodomains. Its expression pattern also overlaps with that of the Receptor Protein tyrosine phosphatase-sigma-binding partner previously localized in muscle, and nucleolin can also be found in retinal basement membranes. We demonstrate that a significant amount of muscle-associated nucleolin is present on the cell surface of developing myotubes, and that two nucleolin-binding components, lactoferrin and the HB-19 peptide, can block the interaction of Receptor Protein tyrosine phosphatase-sigma ectodomains with muscle and retinal basement membranes in tissue sections. These data suggest that muscle cell surface-associated nucleolin represents at least part of the muscle binding site for axonal Receptor Protein tyrosine phosphatase-sigma and that nucleolin may also be a necessary component of basement membrane binding sites of Receptor Protein tyrosine phosphatase-sigma.
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Cell surface nucleolin on developing muscle is a potential ligand for the axonal Receptor Protein tyrosine phosphatase-σ
The FEBS journal, 2006Co-Authors: Daniel E Alete, Mark E Weeks, Ara G Hovanession, Muhamed Hawadle, Andrew W StokerAbstract:Reversible tyrosine phosphorylation, catalyzed by Receptor tyrosine kinases and Receptor tyrosine phosphatases, plays an essential part in cell signaling during axonal development. Receptor Protein tyrosine phosphatase-sigma has been implicated in the growth, guidance and repair of retinal axons. This phosphatase has also been implicated in motor axon growth and innervation. Insect orthologs of Receptor Protein tyrosine phosphatase-sigma are also implicated in the recognition of muscle target cells. A potential extracellular ligand for vertebrate Receptor Protein tyrosine phosphatase-sigma has been previously localized in developing skeletal muscle. The identity of this muscle ligand is currently unknown, but it appears to be unrelated to the heparan sulfate ligands of Receptor Protein tyrosine phosphatase-sigma. In this study, we have used affinity chromatography and tandem MS to identify nucleolin as a binding partner for Receptor Protein tyrosine phosphatase-sigma in skeletal muscle tissue. Nucleolin, both from tissue lysates and in purified form, binds to Receptor Protein tyrosine phosphatase-sigma ectodomains. Its expression pattern also overlaps with that of the Receptor Protein tyrosine phosphatase-sigma-binding partner previously localized in muscle, and nucleolin can also be found in retinal basement membranes. We demonstrate that a significant amount of muscle-associated nucleolin is present on the cell surface of developing myotubes, and that two nucleolin-binding components, lactoferrin and the HB-19 peptide, can block the interaction of Receptor Protein tyrosine phosphatase-sigma ectodomains with muscle and retinal basement membranes in tissue sections. These data suggest that muscle cell surface-associated nucleolin represents at least part of the muscle binding site for axonal Receptor Protein tyrosine phosphatase-sigma and that nucleolin may also be a necessary component of basement membrane binding sites of Receptor Protein tyrosine phosphatase-sigma.
Paola Imbrici - One of the best experts on this subject based on the ideXlab platform.
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Role of Receptor Protein tyrosine phosphatase alpha (RPTPalpha) and tyrosine phosphorylation in the serotonergic inhibition of voltage-dependent potassium channels.
Pfl�gers Archiv European Journal of Physiology, 2000Co-Authors: Paola Imbrici, Stephen J. Tucker, Maria Cristina D'adamo, Mauro PessiaAbstract:The activity of voltage-gated potassium (Kv) channels can be dynamically modulated by several events, including neurotransmitter-stimulated biochemical cascades mediated by G-Protein-coupled Receptors. By using a heterologous expression system, we show that activating the 5-HT2C Receptor inhibits both Kv1.1 and Kv1.2 channels through a tyrosine phosphorylation mechanism. The major molecular determinants of channel inhibition were identified as two tyrosine residues located in the N-terminal region of the Kv channel subunit. Furthermore, we demonstrate that Receptor Protein tyrosine phosphatase alpha (RPTPalpha), a Receptor Protein tyrosine phosphatase, co-ordinates the inhibition process mediated via 5-HT2C Receptors. We therefore propose that the serotonergic regulation of human Kv1.1 and Kv1.2 channel activity by the 5-HT2C Receptor involves the dual coordination of both RPTPalpha and specific tyrosine kinases coupled to this Receptor.
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Role of Receptor Protein tyrosine phosphatase α (RPTPα) and tyrosine phosphorylation in the serotonergic inhibition of voltage-dependent potassium channels
Pflügers Archiv: European Journal of Physiology, 2000Co-Authors: Paola Imbrici, Stephen J. Tucker, Maria Cristina D'adamo, Mauro PessiaAbstract:The activity of voltage-gated potassium (Kv) channels can be dynamically modulated by several events, including neurotransmitter-stimulated biochemical cascades mediated by G-Protein-coupled Receptors. By using a heterologous expression system, we show that activating the 5-HT2C Receptor inhibits both Kv1.1 and Kv1.2 channels through a tyrosine phosphorylation mechanism. The major molecular determinants of channel inhibition were identified as two tyrosine residues located in the N-terminal region of the Kv channel subunit. Furthermore, we demonstrate that Receptor Protein tyrosine phosphatase α (RPTPα), a Receptor Protein tyrosine phosphatase, co-ordinates the inhibition process mediated via 5-HT2C Receptors. We therefore propose that the serotonergic regulation of human Kv1.1 and Kv1.2 channel activity by the 5-HT2C Receptor involves the dual co-ordination of both RPTPα and specific tyrosine kinases coupled to this Receptor.
Vishva M. Dixit - One of the best experts on this subject based on the ideXlab platform.
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the ret Receptor Protein tyrosine kinase associates with the sh2 containing adapter Protein grb10
Journal of Biological Chemistry, 1995Co-Authors: Akhilesh Pandey, Hangjun Duan, Pier Paolo Di Fiore, Vishva M. DixitAbstract:Abstract Ret is a Receptor Protein tyrosine kinase that has been implicated in the development of the enteric nervous, endocrine, and renal systems. Mutations associated with multiple endocrine neoplasia types 2A and 2B (MEN 2A and 2B) have been shown to activate the intrinsic kinase and transforming ability of ret (Santoro, M., Carlomagno, F., Romano, A., Bottaro, D. P., Dathan, N. A., Grieco, M., Fusco, A., Vecchio, G., Matoskova, B., Kraus, M. H., and Paolo DiFiore, P.(1995) Science 267, 381-383). Using the cytoplasmic domain of Ret as bait in a yeast two-hybrid screen of a mouse embryonic library, it was discovered that the src homology 2 (SH2) domain containing Protein Grb10 bound Ret. Grb10 belongs to an emerging family of SH2 containing adapter Proteins, the prototypical member being Grb7. Using glutathione S-transferase fusion Proteins, it was demonstrated that the SH2 domain of Grb10 specifically interacted with Ret. Additionally, using an EGFR/Ret chimera, it was shown that Grb10 bound Ret in an activation dependent manner in vivo. This is the first description of a Receptor Protein tyrosine kinase that utilizes Grb10 as a signaling intermediate.
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Characterization of B61, the Ligand for the Eck Receptor Protein-Tyrosine Kinase
Journal of Biological Chemistry, 1995Co-Authors: Haining Shao, Akhilesh Pandey, K. S. O'shea, M. Seldin, Vishva M. DixitAbstract:Abstract B61 was originally described as a novel secreted tumor necrosis factor-α-inducible gene product in endothelial cells (Holzman, L. B., Marks, R. M., and Dixit, V. M.(1990) Mol. Cell. Biol. 10, 5830-5838). It was recently discovered that soluble recombinant B61 could serve as a ligand for the Eck Receptor Protein-tyrosine kinase, a member of the Eph/Eck subfamily of Receptor Protein-tyrosine kinases (Bartley, T. D., Hunt, R. W., Welcher, A. A., Boyle, W. J., Parker, V. P., Lindberg, R. A., Lu, H. S., Colombero, A. M., Elliott, R. L., Guthrie, R. A., Holst, P. L., Skrine, J. D., Toso, R. J., Zhang, M., Fernandez, E., Trail, G., Yarnum, B., Yarden, Y., Hunter, T., and Fox, G. M.(1994) Nature 368, 558-560). We now show that B61 can also exist as a cell surface glycosylphosphatidylinositol-linked Protein that is capable of activating the Eck Receptor Protein-tyrosine kinase, the first such report of a Receptor Protein-tyrosine kinase ligand that is glycosylphosphatidylinositol-linked. In addition, the expression patterns of B61 and Eck during mouse ontogeny were determined by in situ hybridization. Both were found to be highly expressed in the developing lung and gut, while Eck was preferentially expressed in the thymus. Finally, the gene for B61 was localized to a specific position on mouse chromosome 3 by interspecific backcross analysis.