Abstract
Epidermal growth factor (EGF) induces paxillin tyrosine dephosphorylation and Src activation, but the signaling pathways that mediate these responses were largely undefined. We found that Gab1, a docking protein for the SHP2 protein-tyrosine phosphatase in EGF-stimulated cells, was associated with paxillin. SHP2 dephosphorylated paxillin and caused dissociation of Csk, a negative regulator of Src, from paxillin but had no effect on paxillin-Src association. A lower level of Src Tyr-530 phosphorylation was detected in paxillin-associated Src in EGF-stimulated cells. Expression of an SHP2 binding defective mutant of Gab1 (Gab1FF) or a catalytically inactive mutant of SHP2 (SHP2DN) prevented paxillin tyrosine dephosphorylation and Src activation induced by EGF. Importantly, Gab1FF blocked paxillin-SHP2 complex formation, Src Tyr-530 dephosphorylation, Erk activation, and cell migration induced by EGF. Inhibition of Src tyrosine kinase activity abrogated EGF-stimulated Erk activation and cell migration. Together, these results reveal that Gab1 recruits SHP2 to dephosphorylate paxillin, leading to dissociation of Csk from the paxillin-Src complex and Src activation and that Src is an SHP2 effector involved in EGF-stimulated Erk activation and cell migration.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adaptor Proteins, Signal Transducing
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Binding Sites
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CSK Tyrosine-Protein Kinase
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Cell Movement
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Cytoskeletal Proteins / metabolism*
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Enzyme Activation / drug effects
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Enzyme Inhibitors / pharmacology
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Epidermal Growth Factor / pharmacology*
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Humans
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Intracellular Signaling Peptides and Proteins
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Mitogen-Activated Protein Kinases / metabolism
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Mutation
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Paxillin
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Phosphoproteins / genetics
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Phosphoproteins / metabolism*
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Phosphotyrosine / metabolism*
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Protein Tyrosine Phosphatases / genetics
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Protein Tyrosine Phosphatases / metabolism*
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Protein-Tyrosine Kinases / metabolism
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Recombinant Fusion Proteins
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Transfection
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Tumor Cells, Cultured
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src-Family Kinases / antagonists & inhibitors
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src-Family Kinases / metabolism*
Substances
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Adaptor Proteins, Signal Transducing
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Cytoskeletal Proteins
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Enzyme Inhibitors
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GAB1 protein, human
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Intracellular Signaling Peptides and Proteins
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PXN protein, human
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Paxillin
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Phosphoproteins
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Recombinant Fusion Proteins
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Phosphotyrosine
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Epidermal Growth Factor
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Protein-Tyrosine Kinases
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CSK Tyrosine-Protein Kinase
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src-Family Kinases
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CSK protein, human
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Mitogen-Activated Protein Kinases
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PTPN11 protein, human
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Protein Tyrosine Phosphatases