Src-mediated phosphorylation of Hsp90 in response to vascular endothelial growth factor (VEGF) is required for VEGF receptor-2 signaling to endothelial NO synthase.
Nitric oxide (NO) release from endothelial cells, via endothelial NO synthase (eNOS) activation, is central to the proangiogenic actions of vascular endothelial growth factor (VEGF). VEGF signaling to eNOS is principally mediated by an Akt-dependent phosphorylation of eNOS and by increased association of eNOS to the molecular chaperone, heat-shock protein 90 kDa (Hsp90). Herein, we report that VEGFR-2 activation induces tyrosine phosphorylation of VEGF receptor 2 (VEGFR-2)-associated Hsp90beta. Tyrosine phosphorylation of Hsp90beta in response to VEGF is dependent on internalization of the VEGFR-2 and on Src kinase activation. Furthermore, we demonstrate that c-Src directly phosphorylates Hsp90 on tyrosine 300 residue and that this event is essential for VEGF-stimulated eNOS association to Hsp90 and thus NO release from endothelial cells. Our work identifies Y300 phosphorylation of Hsp90 as a novel regulated posttranslational modification of the chaperone and demonstrates its importance in the proangiogenic actions of VEGF, namely by regulating NO release from endothelial cells.
Duval
Martine
M
Laboratory of Endothelial Cell Biology, Institut de recherches cliniques de Montréal (IRCM), Montréal, QC, H2W 1R7, Canada.
Le Boeuf
Fabrice
F
Huot
Jacques
J
Gratton
Jean-Philippe
JP
D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D008239:Lysine / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D015688:Oncogene Protein pp60(v-src) / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*
D018841:HSP90 Heat-Shock Proteins; D042461:Vascular Endothelial Growth Factor A; D019000:Phosphotyrosine; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D040301:Vascular Endothelial Growth Factor Receptor-2; D015688:Oncogene Protein pp60(v-src); D051057:Proto-Oncogene Proteins c-akt; D008239:Lysine