Vascular endothelial growth factor (VEGF)-driven actin-based motility is mediated by VEGFR2 and requires concerted activation of stress-activated protein kinase 2 (SAPK2/p38) and geldanamycin-sensitive phosphorylation of focal adhesion kinase.
In endothelial cells, vascular endothelial growth factor (VEGF) induces an accumulation of stress fibers associated with new actin polymerization and rapid formation of focal adhesions at the ventral surface of the cells. This cytoskeletal reorganization results in an intense motogenic activity. Using porcine endothelial cells expressing one or the other type of the VEGF receptors, VEGFR1 or VEGFR2, or human umbilical vein endothelial cells pretreated with a VEGFR2 neutralizing antibody, we show that VEGFR2 is responsible for VEGF-induced activation of the stress-activated protein kinase-2/p38 (SAPK2/p38), phosphorylation of focal adhesion kinase (FAK), and enhanced migratory activity. Activation of SAPK2/p38 triggered actin polymerization whereas FAK, which was phosphorylated independently of SAPK2/p38, initiated assembly of focal adhesions. Both processes contributed to the formation of stress fibers. Geldanamycin, an inhibitor of HSP90 blocked tyrosine phosphorylation of FAK, assembly of focal adhesions, actin reorganization, and cell migration, all of which were reversed by overexpressing HSP90. We conclude that VEGFR2 mediates the physiological effect of VEGF on cell migration and that two independent pathways downstream of VEGFR2 regulate actin-based motility. One pathway involves SAPK2/p38 and leads to enhanced actin polymerization activity. The other involves HSP90 as a permissive signal transduction factor implicated in FAK phosphorylation and assembly of focal adhesions.
Rousseau
S
S
Centre de Recherche en Cancérologie de l'Université Laval, L'Hôtel-Dieu de Québec, 11 Côte du Palais, Québec, G1R 2J6, Canada.
Houle
F
F
Kotanides
H
H
Witte
L
L
Waltenberger
J
J
Landry
J
J
Huot
J
J
D000199:Actins / Q000502:physiology*; D000906:Antibodies / Q000494:pharmacology; D016227:Benzoquinones; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002448:Cell Adhesion; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000502:physiology; D016228:Endothelial Growth Factors / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004789:Enzyme Activation; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology; D006801:Humans; D047029:Lactams, Macrocyclic; D008222:Lymphokines / Q000494:pharmacology*; D020928:Mitogen-Activated Protein Kinases; D051419:Paxillin; D010750:Phosphoproteins / Q000502:physiology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000502:physiology; D011809:Quinones / Q000494:pharmacology; D020794:Receptor Protein-Tyrosine Kinases / Q000276:immunology / Q000502:physiology*; D017978:Receptors, Growth Factor / Q000276:immunology / Q000502:physiology*; D040262:Receptors, Vascular Endothelial Growth Factor; D014471:Umbilical Veins; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors; D016596:Vinculin / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases
D000199:Actins; D000906:Antibodies; D016227:Benzoquinones; D003598:Cytoskeletal Proteins; D016228:Endothelial Growth Factors; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D008222:Lymphokines; C496061:PXN protein, human; D051419:Paxillin; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D011809:Quinones; D017978:Receptors, Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D016596:Vinculin; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor; D040281:Vascular Endothelial Growth Factor Receptor-1; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C001277:geldanamycin