Vascular endothelial-cadherin tyrosine phosphorylation in angiogenic and quiescent adult tissues.
Vascular endothelial-cadherin (VE-cadherin) plays a key role in angiogenesis and in vascular permeability. The regulation of its biological activity may be a central mechanism in normal or pathological angiogenesis. VE-cadherin has been shown to be phosphorylated on tyrosine in vitro under various conditions, including stimulation by VEGF. In the present study, we addressed the question of the existence of a tyrosine phosphorylated form of VE-cadherin in vivo, in correlation with the quiescent versus angiogenic state of adult tissues. Phosphorylated VE-cadherin was detected in mouse lung, uterus, and ovary but not in other tissues unless mice were injected with peroxovanadate to block protein phosphatases. Remarkably, VE-cadherin tyrosine phosphorylation was dramatically increased in uterus and ovary, and not in other organs, during PMSG/hCG-induced angiogenesis. In parallel, we observed an increased association of VE-cadherin with Flk1 (VEGF receptor 2) during hormonal angiogenesis. Additionally, Src kinase was constitutively associated with VE-cadherin in both quiescent and angiogenic tissues and increased phosphorylation of VE-cadherin-associated Src was detected in uterus and ovary after hormonal treatment. Src-VE-cadherin association was detected in cultured endothelial cells, independent of VE-cadherin phosphorylation state and Src activation level. In this model, Src inhibition impaired VEGF-induced VE-cadherin phosphorylation, indicating that VE-cadherin phosphorylation was dependent on Src activation. We conclude that VE-cadherin is a substrate for tyrosine kinases in vivo and that its phosphorylation, together with that of associated Src, is increased by angiogenic stimulation. Physical association between Flk1, Src, and VE-cadherin may thus provide an efficient mechanism for amplification and perpetuation of VEGF-stimulated angiogenic processes.
Lambeng
Nathalie
N
INSERM, CEA, Université J. Fourier EMI 02-19, Laboratoire de Développement et Vieillissement de l'Endothélium, Grenoble, France.
Wallez
Yann
Y
Rampon
Christine
C
Cand
Francine
F
Christé
Georges
G
Gulino-Debrac
Danielle
D
Vilgrain
Isabelle
I
Huber
Philippe
P
D000818:Animals; D015820:Cadherins / Q000737:chemistry* / Q000378:metabolism*; D002457:Cell Extracts / Q000737:chemistry; D002460:Cell Line; D042783:Endothelial Cells / Q000737:chemistry / Q000378:metabolism; D004730:Endothelium, Vascular / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism*; D005260:Female; D006064:Gonadotropins, Equine / Q000494:pharmacology; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000037:antagonists & inhibitors / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology; D014599:Uterus / Q000187:drug effects / Q000378:metabolism; D014638:Vanadates / Q000008:administration & dosage / Q000494:pharmacology; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
D015820:Cadherins; D002457:Cell Extracts; C502403:FAT1 protein, human; D006064:Gonadotropins, Equine; D011506:Proteins; C502406:fat1 protein, mouse; C069276:peroxovanadate; D019000:Phosphotyrosine; D014638:Vanadates; D040301:Vascular Endothelial Growth Factor Receptor-2; D016392:Proto-Oncogene Proteins pp60(c-src)