Vascular endothelial cell growth factor promotes tyrosine phosphorylation of mediators of signal transduction that contain SH2 domains. Association with endothelial cell proliferation.
Vascular endothelial cell growth factor (VEGF), an endothelial cell-specific mitogen that plays an important role in angiogenesis, promotes the tyrosine phosphorylation of at least 11 proteins in bovine aortic endothelial cells (BAEC). Proteins immunoprecipitated from lysates of control- and VEGF-stimulated BAEC with antisera to phospholipase C-gamma (PLC-gamma) were fractionated by SDS-polyacrylamide gel electrophoresis and transferred to Immobilon-P. Evaluation of the Western blots with antisera to phosphotyrosine demonstrated that PLC-gamma and two proteins (100 and 85 kDa) that associate with PLC-gamma were phosphorylated in response to VEGF. By using antisera specific to other mediators of signal transduction that contain SH2 domains for immunoprecipitation, it was demonstrated that VEGF promotes phosphorylation of phosphatidylinositol 3-kinase, Ras GTPase activating protein (GAP), and the oncogenic adaptor protein NcK. Proteins of M(r) consistent with the VEGF receptors Flt-1 and Flk-1/KDR were also tyrosine phosphorylated in stimulated cells. Tyrosine-phosphorylated Nck, PLC-gamma, and two GAP-associated proteins, p190 and p62, were in GAP immunoprecipitates of VEGF-stimulated BAEC, and tyrosine-phosphorylated NcK was in phosphatidylinositol 3-kinase immunoprecipitates. These observations suggest that VEGF promotes formation of multimeric aggregates of VEGF receptors with proteins that contain SH2 domains and activate various signaling pathways. VEGF-promoted proliferation of endothelial cells and tyrosine phosphorylation of SH2 domain containing signaling molecules were inhibited by the tyrosine kinase inhibitor genistein.
Guo
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D
Department of Physiology and Biophysics, Indiana University School of Medicine, Indianapolis 46202.
Jia
Q
Q
Song
H Y
HY
Warren
R S
RS
Donner
D B
DB
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D016228:Endothelial Growth Factors / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D008222:Lymphokines / Q000494:pharmacology*; D015513:Oncogene Proteins / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology; D017978:Receptors, Growth Factor / Q000502:physiology; D040262:Receptors, Vascular Endothelial Growth Factor; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D020703:ras GTPase-Activating Proteins
D048868:Adaptor Proteins, Signal Transducing; D016228:Endothelial Growth Factors; D020690:GTPase-Activating Proteins; D008222:Lymphokines; C078332:Nck protein; D015513:Oncogene Proteins; D011506:Proteins; D017978:Receptors, Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D020703:ras GTPase-Activating Proteins; D014443:Tyrosine; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor; D010738:Type C Phospholipases