VEGFR2 induces c-Src signaling and vascular permeability in vivo via the adaptor protein TSAd.
Regulation of vascular endothelial (VE) growth factor (VEGF)-induced permeability is critical in physiological and pathological processes. We show that tyrosine phosphorylation of VEGF receptor 2 (VEGFR2) at Y951 facilitates binding of VEGFR2 to the Rous sarcoma (Src) homology 2-domain of T cell-specific adaptor (TSAd), which in turn regulates VEGF-induced activation ... of the c-Src tyrosine kinase and vascular permeability. c-Src was activated in vivo and in vitro in a VEGF/TSAd-dependent manner, and was regulated via increased phosphorylation at pY418 and reduced phosphorylation at pY527. Tsad silencing blocked VEGF-induced c-Src activation, but did not affect pathways involving phospholipase Cγ, extracellular regulated kinase, and endothelial nitric oxide. VEGF-induced rearrangement of VE-cadherin-positive junctions in endothelial cells isolated from mouse lungs, or in mouse cremaster vessels, was dependent on TSAd expression, and TSAd formed a complex with VE-cadherin, VEGFR2, and c-Src at endothelial junctions. Vessels in tsad(-/-) mice showed undisturbed flow and pressure, but impaired VEGF-induced permeability, as measured by extravasation of Evans blue, dextran, and microspheres in the skin and the trachea. Histamine-induced extravasation was not affected by TSAd deficiency. We conclude that TSAd is required for VEGF-induced, c-Src-mediated regulation of endothelial cell junctions and for vascular permeability.
Mesh Terms:
Adaptor Proteins, Signal Transducing, Animals, Antigens, CD, Blotting, Western, Cadherins, Capillary Permeability, Cells, Cultured, Endothelial Cells, Extravasation of Diagnostic and Therapeutic Materials, Female, Fluorescein-5-isothiocyanate, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Microscopy, Confocal, Microspheres, Phosphorylation, Protein Binding, RNA Interference, Signal Transduction, Vascular Endothelial Growth Factor A, Vascular Endothelial Growth Factor Receptor-2, src-Family Kinases
Adaptor Proteins, Signal Transducing, Animals, Antigens, CD, Blotting, Western, Cadherins, Capillary Permeability, Cells, Cultured, Endothelial Cells, Extravasation of Diagnostic and Therapeutic Materials, Female, Fluorescein-5-isothiocyanate, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Microscopy, Confocal, Microspheres, Phosphorylation, Protein Binding, RNA Interference, Signal Transduction, Vascular Endothelial Growth Factor A, Vascular Endothelial Growth Factor Receptor-2, src-Family Kinases
J. Exp. Med.
Date: Jul. 02, 2012
PubMed ID: 22689825
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