Abstract
SHPS-1 is an approximately 120 kDa glycosylated receptor like protein that contains three immunoglobulin-like domains in its extracellular region as well as four potential tyrosine phosphorylation and SRC homology 2 (SH2) domain binding sites in its cytoplasmic region. Lysophosphatidic acid (LPA) stimulated the rapid tyrosine phosphorylation of SHPS-1 and its subsequent association with SHP-2, a protein tyrosine phosphatase containing SH2 domains in Rat-1 fibroblasts. LAP-induced tyrosine phosphorylation of SHPS-1 was inhibited by Clostridium botulinum C3 exoenzyme (which inactivates RHO) but not by pertussis toxin. The protein kinase C activator phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA) also stimulated tyrosine phosphorylation of SHPS-1; however, down-regulation of protein kinase C by prolonged exposure of cells to TPA did not affect LAP-induced tyrosine phosphorylation of SHPS-1. LPA-induced tyrosine phosphorylation of SHPS-1 was markedly reduced in either focal adhesion kinase (FAK)-deficient mouse cells or CHO cells overexpressing the tyrosine kinase CSK. Overexpression of a catalytically inactivate SHP-2 markedly inhibited MAP kinase activation in response to low concentrations of LPA in CHO cells, whereas overexpression of a wild-type SHPS-1 did enhance this effect of LPA. Furthermore, MAP kinase activation in response to a low concentration of LPA was inhibited by botulinum C3 exoenzyme. These results indicate that LPA-induced tyrosine phosphorylation of SHPS-1 and its association with SHP-2 may be mediated by a RHO-dependent pathway that includes FAK and a SRC family kinase. Thus, in addition to its role in receptor tyrosine kinase-mediated MAP kinase activation, the formation of a complex between SHPS-1 and SHP-2 may, in part, play an important role in the activation of MAP kinase in response to low concentrations of LPA.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ADP Ribose Transferases / pharmacology
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Animals
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Antigens, Differentiation*
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Botulinum Toxins*
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CHO Cells
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Calcium-Calmodulin-Dependent Protein Kinases / metabolism
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Catalysis
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Cell Adhesion Molecules / genetics
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Cell Adhesion Molecules / physiology*
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Cell Line
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Cricetinae
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Enzyme Activation
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Focal Adhesion Kinase 1
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Focal Adhesion Protein-Tyrosine Kinases
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GTP-Binding Proteins / physiology*
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Humans
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Intracellular Signaling Peptides and Proteins
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Lysophospholipids / metabolism*
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Lysophospholipids / pharmacology
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Membrane Glycoproteins / metabolism*
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Mice
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Mice, Inbred BALB C
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Neural Cell Adhesion Molecule L1*
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Neural Cell Adhesion Molecules / metabolism*
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Pertussis Toxin
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Phosphorylation
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Protein Kinase C / physiology
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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 / metabolism*
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / physiology*
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Rats
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Receptors, Immunologic*
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SH2 Domain-Containing Protein Tyrosine Phosphatases
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Tyrosine / metabolism
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Virulence Factors, Bordetella / pharmacology
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rho GTP-Binding Proteins
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src-Family Kinases / physiology*
Substances
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Antigens, Differentiation
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Cell Adhesion Molecules
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Intracellular Signaling Peptides and Proteins
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Lysophospholipids
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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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Sirpa protein, mouse
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Receptors, Immunologic
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SIRPA protein, human
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Sirpa protein, rat
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Virulence Factors, Bordetella
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Tyrosine
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ADP Ribose Transferases
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exoenzyme C3, Clostridium botulinum
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Pertussis Toxin
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Protein-Tyrosine Kinases
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Focal Adhesion Kinase 1
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Focal Adhesion Protein-Tyrosine Kinases
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PTK2 protein, human
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Ptk2 protein, mouse
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Ptk2 protein, rat
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src-Family Kinases
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Protein Kinase C
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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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Ptpn11 protein, mouse
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Ptpn11 protein, rat
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Ptpn6 protein, mouse
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Ptpn6 protein, rat
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SH2 Domain-Containing Protein Tyrosine Phosphatases
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Botulinum Toxins
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GTP-Binding Proteins
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rho GTP-Binding Proteins