Figure 2

Signaling pathways activated by VEGF. VEGF regulates several
endothelial cell functions, including proliferation, diff erentiation, permeability,
vascular tone, and the production of vasoactive molecules. Upon ligand binding,
the receptor tyrosines are phosphorylated, allowing the receptor to associate with
a range of signaling molecules, including phosphatidylinositol 3-kinase (PI3K), Shc,
Grb2, and the phosphatases SHP-1 and SHP-2. VEGF receptor activation can induce
activation of the MAPK cascade via Raf stimulation leading to gene expression and
cell proliferation, activation of PI3K leading to PKB activation and cell survival, activation
of PLC-γ leading to cell proliferation, vasopermeability, and angiogenesis.