The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Robert Roskoski - One of the best experts on this subject based on the ideXlab platform.
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Signaling by Kit protein-tyrosine kinase—The stem cell factor receptor
Biochemical and biophysical research communications, 2005Co-Authors: Robert RoskoskiAbstract:Signaling by stem cell factor and Kit, its receptor, plays important roles in gametogenesis, hematopoiesis, mast cell development and function, and melanogenesis. Moreover, human and mouse embryonic stem cells express Kit transcripts. Stem cell factor exists as both a soluble and a membrane-bound glycoprotein while Kit is a receptor protein-tyrosine kinase. The complete absence of stem cell factor or Kit is lethal. Deficiencies of either produce defects in red and white blood cell production, hypopigmentation, and sterility. Gain-of-function mutations of Kit are associated with several human neoplasms including acute myelogenous leukemia, gastrointestinal stromal tumors, and mastocytomas. Kit consists of an extracellular domain, a transmembrane segment, a juxtamembrane segment, and a protein kinase domain that contains an insert of about 80 amino acid residues. Binding of stem cell factor to Kit results in receptor dimerization and activation of protein kinase activity. The activated receptor becomes autophosphorylated at tyrosine residues that serve as docking sites for signal transduction molecules containing SH2 domains. The adaptor protein APS, Src family kinases, and Shp2 tyrosyl phosphatase bind to Phosphotyrosine 568. Shp1 tyrosyl phosphatase and the adaptor protein Shc bind to Phosphotyrosine 570. C-terminal Src kinase homologous kinase and the adaptor Shc bind to both Phosphotyrosines 568 and 570. These residues occur in the juxtamembrane segment of Kit. Three residues in the kinase insert domain are phosphorylated and attract the adaptor protein Grb2 (Tyr703), phosphatidylinositol 3-kinase (Tyr721), and phospholipase Cgamma (Tyr730). Phosphotyrosine 900 in the distal kinase domain binds phosphatidylinositol 3-kinase which in turn binds the adaptor protein Crk. Phosphotyrosine 936, also in the distal kinase domain, binds the adaptor proteins APS, Grb2, and Grb7. Kit has the potential to participate in multiple signal transduction pathways as a result of interaction with several enzymes and adaptor proteins.
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signaling by kit protein tyrosine kinase the stem cell factor receptor
Biochemical and Biophysical Research Communications, 2005Co-Authors: Robert RoskoskiAbstract:Signaling by stem cell factor and Kit, its receptor, plays important roles in gametogenesis, hematopoiesis, mast cell development and function, and melanogenesis. Moreover, human and mouse embryonic stem cells express Kit transcripts. Stem cell factor exists as both a soluble and a membrane-bound glycoprotein while Kit is a receptor protein-tyrosine kinase. The complete absence of stem cell factor or Kit is lethal. Deficiencies of either produce defects in red and white blood cell production, hypopigmentation, and sterility. Gain-of-function mutations of Kit are associated with several human neoplasms including acute myelogenous leukemia, gastrointestinal stromal tumors, and mastocytomas. Kit consists of an extracellular domain, a transmembrane segment, a juxtamembrane segment, and a protein kinase domain that contains an insert of about 80 amino acid residues. Binding of stem cell factor to Kit results in receptor dimerization and activation of protein kinase activity. The activated receptor becomes autophosphorylated at tyrosine residues that serve as docking sites for signal transduction molecules containing SH2 domains. The adaptor protein APS, Src family kinases, and Shp2 tyrosyl phosphatase bind to Phosphotyrosine 568. Shp1 tyrosyl phosphatase and the adaptor protein Shc bind to Phosphotyrosine 570. C-terminal Src kinase homologous kinase and the adaptor Shc bind to both Phosphotyrosines 568 and 570. These residues occur in the juxtamembrane segment of Kit. Three residues in the kinase insert domain are phosphorylated and attract the adaptor protein Grb2 (Tyr703), phosphatidylinositol 3-kinase (Tyr721), and phospholipase Cgamma (Tyr730). Phosphotyrosine 900 in the distal kinase domain binds phosphatidylinositol 3-kinase which in turn binds the adaptor protein Crk. Phosphotyrosine 936, also in the distal kinase domain, binds the adaptor proteins APS, Grb2, and Grb7. Kit has the potential to participate in multiple signal transduction pathways as a result of interaction with several enzymes and adaptor proteins.
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src kinase regulation by phosphorylation and dephosphorylation
Biochemical and Biophysical Research Communications, 2005Co-Authors: Robert RoskoskiAbstract:Abstract Src and Src-family protein-tyrosine kinases are regulatory proteins that play key roles in cell differentiation, motility, proliferation, and survival. The initially described phosphorylation sites of Src include an activating Phosphotyrosine 416 that results from autophosphorylation, and an inhibiting Phosphotyrosine 527 that results from phosphorylation by C-terminal Src kinase (Csk) and Csk homologous kinase. Dephosphorylation of Phosphotyrosine 527 increases Src kinase activity. Candidate Phosphotyrosine 527 phosphatases include cytoplasmic PTP1B, Shp1 and Shp2, and transmembrane enzymes include CD45, PTPα, PTPe, and PTPλ. Dephosphorylation of Phosphotyrosine 416 decreases Src kinase activity. Thus far PTP-BL, the mouse homologue of human PTP-BAS, has been shown to dephosphorylate Phosphotyrosine 416 in a regulatory fashion. The platelet-derived growth factor receptor protein-tyrosine kinase mediates the phosphorylation of Src Tyr138; this phosphorylation has no direct effect on Src kinase activity. The platelet-derived growth factor receptor and the ErbB2/HER2 growth factor receptor protein-tyrosine kinases mediate the phosphorylation of Src Tyr213 and activation of Src kinase activity. Src kinase is also a substrate for protein-serine/threonine kinases including protein kinase C (Ser12), protein kinase A (Ser17), and CDK1/cdc2 (Thr34, Thr46, and Ser72). Of the three protein-serine/threonine kinases, only phosphorylation by CDK1/cdc2 has been demonstrated to increase Src kinase activity. Although considerable information on the phosphoprotein phosphatases that catalyze the hydrolysis of Src Phosphotyrosine 527 is at hand, the nature of the phosphatases that mediate the hydrolysis of Phosphotyrosine 138 and 213, and phosphoserine and phosphothreonine residues has not been determined.
Lewis C. Cantley - One of the best experts on this subject based on the ideXlab platform.
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pyruvate kinase m2 is a Phosphotyrosine binding protein
Nature, 2008Co-Authors: Heather R Christofk, Matthew Vander G Heiden, John M Asara, Lewis C. CantleyAbstract:Growth factors stimulate cells to take up excess nutrients and to use them for anabolic processes. The biochemical mechanism by which this is accomplished is not fully understood but it is initiated by phosphorylation of signalling proteins on tyrosine residues. Using a novel proteomic screen for Phosphotyrosine-binding proteins, we have made the observation that an enzyme involved in glycolysis, the human M2 (fetal) isoform of pyruvate kinase (PKM2), binds directly and selectively to tyrosine-phosphorylated peptides. We show that binding of Phosphotyrosine peptides to PKM2 results in release of the allosteric activator fructose-1,6-bisphosphate, leading to inhibition of PKM2 enzymatic activity. We also provide evidence that this regulation of PKM2 by Phosphotyrosine signalling diverts glucose metabolites from energy production to anabolic processes when cells are stimulated by certain growth factors. Collectively, our results indicate that expression of this Phosphotyrosine-binding form of pyruvate kinase is critical for rapid growth in cancer cells.
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The C2 domain of PKCdelta is a Phosphotyrosine binding domain.
Cell, 2005Co-Authors: Cyril H. Benes, Lewis C. Cantley, Andrew E. H. Elia, Tejal Dharia, Stephen P. SoltoffAbstract:In eukaryotic cells, the SH2 and PTB domains mediate protein-protein interactions by recognizing Phosphotyrosine residues on target proteins. Here we make the unexpected finding that the C2 domain of PKCdelta directly binds to Phosphotyrosine peptides in a sequence-specific manner. We provide evidence that this domain mediates PKCdelta interaction with a Src binding glycoprotein, CDCP1. The crystal structure of the PKCdelta C2 domain in complex with an optimal phosphopeptide reveals a new mode of Phosphotyrosine binding in which the Phosphotyrosine moiety forms a ring-stacking interaction with a histidine residue of the C2 domain. This is also the first example of a protein Ser/Thr kinase containing a domain that binds Phosphotyrosine.
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The Phosphotyrosine Interaction Domain of SHC Recognizes Tyrosine-phosphorylated NPXY Motif
The Journal of biological chemistry, 1995Co-Authors: Zhou Songyang, B. Margolis, Manas Chaudhuri, Steve E. Shoelson, Lewis C. CantleyAbstract:Abstract Reversible assembly of intracellular signaling complexes is, in some cases, mediated by direct binding of a Src homology 2 (SH2) domain of one protein to a Phosphotyrosine moiety of another protein (Cantley, L. C., Auger, K. R., Carpenter, C. L., Duckworth, B., Graziani, A., Kapeller, R., and Soltoff, S.(1991) Cell 64, 281-302). Using a degenerate Phosphotyrosine-containing peptide library, we showed that individual SH2 domains recognize Phosphotyrosine in a specific sequence context to provide fidelity in signaling (Songyang, Z., Shoelson, S. E., Chaudhuri, M., Gish, G., Pawson, T., Haser, W. G., King, F., Roberts, T., Ratnofsky, S., Lechleider, R. J., Neel, B. G., Birge, R. B., Fajardo, J. E., Chou, M. M., Hanafusa, H., Schaffhausen, B., and Cantley, L. C.(1993) Cell 72, 767-778). Recently a second type of Phosphotyrosine interaction domain (PID) or Phosphotyrosine-binding domain (PTB) was discovered in the amino terminus of the SHC proto-oncoprotein (Kavanaugh, W. M., and Williams, L.(1994) Science 266, 1862-1865; Blaikie, P., Immanuel, D., Wu, J., Li, N., Yajnik, V., and Margolis, B.(1994) J. Biol. Chem. 269, 32031-32034). Here we demonstrate, using a Phosphotyrosine peptide library, that the SHC PID domain preferentially binds to the sequence Asn-Pro-Xaa-Phosphotyrosine. This motif is in agreement with sequences at sites implicated in in vivo SHC binding. These results indicate that while SH2 domains predominantly interact with specific residues carboxyl-terminal of Phosphotyrosine, the PID domain has high specificity for residues amino-terminal of Phosphotyrosine.
Lei Wang - One of the best experts on this subject based on the ideXlab platform.
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Site-specific incorporation of Phosphotyrosine using an expanded genetic code
Nature Chemical Biology, 2017Co-Authors: Christian Hoppmann, Allison Wong, Bing Yang, Tony Hunter, Kevan M Shokat, Lei WangAbstract:Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key to understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active Phosphotyrosine-containing proteins by genetically encoding a stable Phosphotyrosine analog that is convertible to native Phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, Phosphotyrosine sites and functions, and reveal a possible role of tyrosine phosphorylation in negative regulation of ubiquitination. A genetically encoded unnatural amino acid analog and its acidic deprotection enable the site-specific incorporation of Phosphotyrosine (pTyr) into proteins such as ubiquitin, where it can be used to study the function of this phosphorylated residue.
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site specific incorporation of Phosphotyrosine using an expanded genetic code
Nature Chemical Biology, 2017Co-Authors: Christian Hoppmann, Bing Yang, Tony Hunter, Kevan M Shokat, Allison W Wong, Lei WangAbstract:Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key to understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active Phosphotyrosine-containing proteins by genetically encoding a stable Phosphotyrosine analog that is convertible to native Phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, Phosphotyrosine sites and functions, and reveal a possible role of tyrosine phosphorylation in negative regulation of ubiquitination.
B. Margolis - One of the best experts on this subject based on the ideXlab platform.
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The Phosphotyrosine interaction domain of Shc binds an LXNPXY motif on the epidermal growth factor receptor.
Molecular and cellular biology, 1995Co-Authors: A. Batzer, P Blaikie, K Nelson, Joseph Schlessinger, B. MargolisAbstract:Shc is an SH2 domain protein that is tyrosine phosphorylated in cells stimulated with a variety of growth factors and cytokines. Once phosphorylated, Shc binds the Grb2-Sos complex, leading to Ras activation. Shc can interact with tyrosine-phosphorylated proteins by binding to Phosphotyrosine in the context of an NPXpY motif, where pY is a Phosphotyrosine. This is an unusual binding site for an SH2 domain protein whose binding specificity is usually controlled by residues carboxy terminal, not amino terminal, to the Phosphotyrosine. Recently we identified a second region in Shc, named the Phosphotyrosine interaction (PI) domain, and we have found it to be present in a variety of other cellular proteins. In this study we used a dephosphorylation protection assay, competition analysis with Phosphotyrosine-containing synthetic peptides, and epidermal growth factor receptor (EGFR) mutants to determine the binding sites of the PI domain of Shc on the EGFR. We demonstrate that the PI domain of Shc binds the LXNPXpY motif that encompasses Y-1148 of the activated EGFR. We conclude that the PI domain imparts to Shc its ability to bind the NPXpY motif.
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The Phosphotyrosine Interaction Domain of SHC Recognizes Tyrosine-phosphorylated NPXY Motif
The Journal of biological chemistry, 1995Co-Authors: Zhou Songyang, B. Margolis, Manas Chaudhuri, Steve E. Shoelson, Lewis C. CantleyAbstract:Abstract Reversible assembly of intracellular signaling complexes is, in some cases, mediated by direct binding of a Src homology 2 (SH2) domain of one protein to a Phosphotyrosine moiety of another protein (Cantley, L. C., Auger, K. R., Carpenter, C. L., Duckworth, B., Graziani, A., Kapeller, R., and Soltoff, S.(1991) Cell 64, 281-302). Using a degenerate Phosphotyrosine-containing peptide library, we showed that individual SH2 domains recognize Phosphotyrosine in a specific sequence context to provide fidelity in signaling (Songyang, Z., Shoelson, S. E., Chaudhuri, M., Gish, G., Pawson, T., Haser, W. G., King, F., Roberts, T., Ratnofsky, S., Lechleider, R. J., Neel, B. G., Birge, R. B., Fajardo, J. E., Chou, M. M., Hanafusa, H., Schaffhausen, B., and Cantley, L. C.(1993) Cell 72, 767-778). Recently a second type of Phosphotyrosine interaction domain (PID) or Phosphotyrosine-binding domain (PTB) was discovered in the amino terminus of the SHC proto-oncoprotein (Kavanaugh, W. M., and Williams, L.(1994) Science 266, 1862-1865; Blaikie, P., Immanuel, D., Wu, J., Li, N., Yajnik, V., and Margolis, B.(1994) J. Biol. Chem. 269, 32031-32034). Here we demonstrate, using a Phosphotyrosine peptide library, that the SHC PID domain preferentially binds to the sequence Asn-Pro-Xaa-Phosphotyrosine. This motif is in agreement with sequences at sites implicated in in vivo SHC binding. These results indicate that while SH2 domains predominantly interact with specific residues carboxyl-terminal of Phosphotyrosine, the PID domain has high specificity for residues amino-terminal of Phosphotyrosine.
Christian Hoppmann - One of the best experts on this subject based on the ideXlab platform.
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Site-specific incorporation of Phosphotyrosine using an expanded genetic code
Nature Chemical Biology, 2017Co-Authors: Christian Hoppmann, Allison Wong, Bing Yang, Tony Hunter, Kevan M Shokat, Lei WangAbstract:Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key to understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active Phosphotyrosine-containing proteins by genetically encoding a stable Phosphotyrosine analog that is convertible to native Phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, Phosphotyrosine sites and functions, and reveal a possible role of tyrosine phosphorylation in negative regulation of ubiquitination. A genetically encoded unnatural amino acid analog and its acidic deprotection enable the site-specific incorporation of Phosphotyrosine (pTyr) into proteins such as ubiquitin, where it can be used to study the function of this phosphorylated residue.
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site specific incorporation of Phosphotyrosine using an expanded genetic code
Nature Chemical Biology, 2017Co-Authors: Christian Hoppmann, Bing Yang, Tony Hunter, Kevan M Shokat, Allison W Wong, Lei WangAbstract:Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key to understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active Phosphotyrosine-containing proteins by genetically encoding a stable Phosphotyrosine analog that is convertible to native Phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, Phosphotyrosine sites and functions, and reveal a possible role of tyrosine phosphorylation in negative regulation of ubiquitination.