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Ligand‐Stimulated VEGFR2 Signaling is Regulated by Co‐Ordinated Trafficking and Proteolysis
Author(s) -
Bruns Alexander F.,
Herbert Shane P.,
Odell Adam F.,
Jopling Helen M.,
Hooper Nigel M.,
Zachary Ian C.,
Walker John H.,
Ponnambalam Sreenivasan
Publication year - 2010
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2009.01001.x
Subject(s) - microbiology and biotechnology , biology , phosphorylation , signal transduction , angiogenesis , receptor tyrosine kinase , kinase insert domain receptor , proteasome , proteolysis , protein kinase b , vascular endothelial growth factor a , vascular endothelial growth factor , biochemistry , cancer research , vegf receptors , enzyme
Vascular endothelial growth factor A (VEGF‐A)‐induced signaling through VEGF receptor 2 (VEGFR2) regulates both physiological and pathological angiogenesis in mammals. However, the temporal and spatial mechanism underlying VEGFR2‐mediated intracellular signaling is not clear. Here, we define a pathway for VEGFR2 trafficking and proteolysis that regulates VEGF‐A‐stimulated signaling and endothelial cell migration. Ligand‐stimulated VEGFR2 activation and ubiquitination preceded proteolysis and cytoplasmic domain removal associated with endosomes. A soluble VEGFR2 cytoplasmic domain fragment displayed tyrosine phosphorylation and activation of downstream intracellular signaling. Perturbation of endocytosis by the depletion of either clathrin heavy chain or an ESCRT‐0 subunit caused differential effects on ligand‐stimulated VEGFR2 proteolysis and signaling. This novel VEGFR2 proteolysis was blocked by the inhibitors of 26S proteasome activity. Inhibition of proteasome activity prolonged VEGF‐A‐induced intracellular signaling to c‐Akt and endothelial nitric oxide synthase (eNOS). VEGF‐A‐stimulated endothelial cell migration was dependent on VEGFR2 and VEGFR tyrosine kinase activity. Inhibition of proteasome activity in this assay stimulated VEGF‐A‐mediated endothelial cell migration. VEGFR2 endocytosis, ubiquitination and proteolysis could also be stimulated by a protein kinase C‐dependent pathway. Thus, removal of the VEGFR2 carboxyl terminus linked to phosphorylation, ubiquitination and trafficking is necessary for VEGF‐stimulated endothelial signaling and cell migration.