Abstract
Tek/Tie-2 is an endothelial cell (EC)-specific receptor tyrosine kinase that plays a critical role in angiogenesis via its regulation by the angiopoietin family of growth factor ligands. Angiopoietin-1 (Ang1) can promote EC migration; however, the signaling mechanisms underlying this process remain elusive. Here we demonstrate that Dok-R/Dok-2 can associate with Tek in ECs following Ang1 stimulation, resulting in tyrosine phosphorylation of Dok-R and the subsequent recruitment of Nck and the p21-activating kinase (Pak/Pak1) to the activated receptor. Ang1-mediated migration is increased upon Dok-R overexpression and this requires a functional Nck binding site on Dok-R. Localization of this Dok-R-Nck-Pak complex to the activated Tek receptor at the cellular membrane is coincident with activation of Pak kinase. The ability of Dok-R to bind Nck is required for maximal activation of Pak and overexpression of Pak results in increased Ang1-mediated cell motility. Our study outlines a novel signaling pathway underlying Ang1-driven cell migration that involves Dok-R and its recruitment of Nck and the subsequent activation of Pak.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Angiopoietin-1
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Binding Sites / physiology
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Carrier Proteins / genetics
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Carrier Proteins / metabolism*
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Cell Line
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Cell Movement / drug effects
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Cell Movement / physiology
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Endothelium, Vascular / cytology
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Endothelium, Vascular / drug effects
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Endothelium, Vascular / metabolism
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Enzyme Activation / drug effects
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Enzyme Activation / physiology
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Epithelial Cells / cytology
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Epithelial Cells / metabolism
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Humans
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Kidney / cytology
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Kidney / drug effects
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Kidney / metabolism
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Macromolecular Substances
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Membrane Glycoproteins / pharmacology*
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Oncogene Proteins / metabolism
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Phosphoproteins / genetics
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Phosphoproteins / metabolism*
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Phosphorylation / drug effects
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Protein Binding / physiology
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Protein Serine-Threonine Kinases / metabolism*
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Receptor Protein-Tyrosine Kinases / metabolism
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Receptor, TIE-2
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Signal Transduction / drug effects
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Signal Transduction / physiology
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p21-Activated Kinases
Substances
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Adaptor Proteins, Signal Transducing
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Angiopoietin-1
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Carrier Proteins
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DOK2 protein, human
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Macromolecular Substances
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Membrane Glycoproteins
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Nck protein
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Oncogene Proteins
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Phosphoproteins
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Receptor Protein-Tyrosine Kinases
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Receptor, TIE-2
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PAK1 protein, human
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Protein Serine-Threonine Kinases
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p21-Activated Kinases