Abstract
SHPS-1 is a receptor-like protein that undergoes tyrosine phosphorylation and binds SHP-2, an SH2 domain-containing protein tyrosine phosphatase, in response to insulin and other mitogens. The overexpression of wild-type SHPS-1, but not of a mutant SHPS-1 in which all four tyrosine residues in its cytoplasmic region were mutated to phenylalanine, markedly enhanced insulin-induced activation of mitogen-activated protein kinase in Chinese hamster ovary cells that overexpress the human insulin receptor. Mutation of each tyrosine residue individually revealed that the major sites of tyrosine phosphorylation of SHPS-1 in response to insulin are Tyr449 and Tyr473. In addition, mutation of either Tyr449 or Tyr473 abolished the insulin-induced tyrosine phosphorylation of SHPS-1 and its association with SHP-2. Surface plasmon resonance analysis showed that glutathione S-transferase fusion proteins containing the NH2-terminal or COOH-terminal SH2 domains of SHP-2 bound preferentially to phosphotyrosyl peptides corresponding to the sequences surrounding Tyr449 or Tyr473, respectively, of SHPS-1. Furthermore, phosphotyrosyl peptides containing Tyr449 or Tyr473 were effective substrates for the phosphatase activity of recombinant SHP-2 in vitro. Together, these results suggest that insulin may induce phosphorylation of SHPS-1 at Tyr449 and Tyr473, to which SHP-2 then binds through its NH2-terminal and COOH-terminal SH2 domains, respectively. SHPS-1 may play a crucial role both in the recruitment of SHP-2 from the cytosol to a site near the plasma membrane and in increasing its catalytic activity, thereby positively regulating the RAS-mitogen-activated protein kinase signaling cascade in response to insulin.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Antigens, Differentiation*
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Binding Sites
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CHO Cells
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Calcium-Calmodulin-Dependent Protein Kinases / metabolism*
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Cricetinae
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DNA Primers
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Enzyme Activation
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Humans
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Insulin / pharmacology*
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Intracellular Signaling Peptides and Proteins
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Kinetics
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Membrane Glycoproteins / biosynthesis
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Membrane Glycoproteins / isolation & purification
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Membrane Glycoproteins / metabolism*
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Mutagenesis, Site-Directed
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Neural Cell Adhesion Molecule L1*
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Neural Cell Adhesion Molecules / biosynthesis
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Neural Cell Adhesion Molecules / isolation & purification
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Neural Cell Adhesion Molecules / metabolism*
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Peptide Fragments / chemistry
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Polymerase Chain Reaction
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Protein Tyrosine Phosphatases / biosynthesis
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Protein Tyrosine Phosphatases / isolation & purification
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Protein Tyrosine Phosphatases / metabolism*
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Receptor, Insulin / biosynthesis
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Receptor, Insulin / physiology*
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Receptors, Immunologic*
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Recombinant Proteins / biosynthesis
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Recombinant Proteins / isolation & purification
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Recombinant Proteins / metabolism
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SH2 Domain-Containing Protein Tyrosine Phosphatases
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Transfection
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src Homology Domains
Substances
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Antigens, Differentiation
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DNA Primers
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Insulin
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Intracellular Signaling Peptides and Proteins
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Membrane Glycoproteins
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Neural Cell Adhesion Molecule L1
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Neural Cell Adhesion Molecules
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Peptide Fragments
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Receptors, Immunologic
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Recombinant Proteins
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SIRPA protein, human
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Receptor, Insulin
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Calcium-Calmodulin-Dependent Protein Kinases
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PTPN11 protein, human
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PTPN6 protein, human
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Protein Tyrosine Phosphatases
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SH2 Domain-Containing Protein Tyrosine Phosphatases