Figure 4.

Signaling of the VEGF Ligands, Receptors, and the Inhibitors of the VEGFA Pathway. The VEGF family of ligands and their receptor-binding patterns are shown at the top. VEGF ligand family members, VEGFA, -B, -C, -D, and placental growth factor (PIGF), selectively bind to three tyrosine kinase receptors, VEGFR1, VEGFR2, and VEGFR3. As co-receptors of VEGFR2 and VEGFR3, neuropilin 1 and 2 (NRP1 and NRP2) modulate their signaling pathways. The soluble VEGFR1 (sVEGFR1) inhibits the signaling of VEGFR1 and VEGFR2 by sequestering free ligands. The different VEGF pathway inhibitors and their targets are indicated with red. Downstream VEGFR signaling pathways are shown on the bottom. VEGFR activates many proteins through PKC or PI3K. The activation of downstream signal transduction molecules leads to numerous distinct biological processes as indicated in the diagram. ¹³⁹