title: Activation of SRC tyrosine kinases in response to ICAM-1 ligation in pulmonary microvascular endothelial cells.
abstract: Previous studies demonstrated that ICAM-1 ligation on human pulmonary microvascular endothelial cells (ECs) sequentially induces activation of xanthine oxidase and p38 MAPK. Inhibition of these signaling events reduces neutrophil migration to the EC borders. This study examined the role of SRC tyrosine kinases in ICAM-1-initiated signaling within these ECs. Cross-linking ICAM-1 on tumor necrosis factor-alpha-pretreated ECs induced an increase in the activity of SRC tyrosine kinases. This increase was inhibited by allopurinol (a xanthine oxidase inhibitor), Me2SO (a hydroxyl radical scavenger), or deferoxamine (an iron chelator). Phenylarsine oxide, a tyrosine phosphatase inhibitor, reduced the base-line activity of SRC as well as the increase in SRC activity induced by ICAM-1 cross-linking. Specific inhibition of the protein expression of the SRC homology 2-containing protein-tyrosine phosphatase-2 (SHP-2) by an antisense oligonucleotide prevented the induced SRC activation but had no effect on the basal SRC activity. Activation of SRC tyrosine kinases was accompanied by tyrosine phosphorylation of ezrin at Tyr-146, which was inhibited by PP2, an SRC tyrosine kinase inhibitor. Moreover, PP2 completely inhibited p38 activation, suggesting a role for SRC tyrosine kinases in p38 activation. These data demonstrate that ICAM-1 ligation activates SRC tyrosine kinases and that this activation requires SHP-2 as well as production of reactive oxygen species generated from xanthine oxidase. Activation of SRC tyrosine kinases in turn leads to tyrosine phosphorylation of ezrin, as well as activation of p38, a kinase previously identified to be required for cytoskeletal changes induced by ICAM-1 ligation and for neutrophil migration along the EC surface.
mesh_terms: D000493:Allopurinol / Q000494:pharmacology; D000818:Animals; D001152:Arsenicals / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D003598:Cytoskeletal Proteins; D003676:Deferoxamine / Q000494:pharmacology; D003902:Detergents / Q000494:pharmacology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000378:metabolism*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008168:Lung / Q000098:blood supply*; D051379:Mice; D008833:Microcirculation / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011233:Precipitin Tests; D054648:Protein Phosphatase 2; D017434:Protein Structure, Tertiary; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013912:Threonine / Q000737:chemistry; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014443:Tyrosine / Q000737:chemistry; D014969:Xanthine Oxidase / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases; D019061:src-Family Kinases / Q000737:chemistry / Q000378:metabolism*; D000099149:Ezrin
chemical_list: D000493:Allopurinol; D001152:Arsenicals; D002614:Chelating Agents; D003432:Cross-Linking Reagents; D003598:Cytoskeletal Proteins; D003676:Deferoxamine; D003902:Detergents; D004121:Dimethyl Sulfoxide; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D018799:Intercellular Adhesion Molecule-1; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D016376:Oligonucleotides, Antisense; D010750:Phosphoproteins; D054648:Protein Phosphatase 2; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D013912:Threonine; D014409:Tumor Necrosis Factor-alpha; D014443:Tyrosine; D014969:Xanthine Oxidase; D048051:p38 Mitogen-Activated Protein Kinases; D019061:src-Family Kinases; D000099149:Ezrin; C029341:oxophenylarsine; C516724:PTPN11 protein, human; C516725:Ptpn11 protein, mouse