Fig. 3.

Scg3 and VEGF have distinct receptor signaling pathways. Scg3 does not bind to VEGFR1 or VEGFR2. Scg3 cannot activate VEGFR2. VEGF activates Src, MEK, ERK1/2, Akt, and Stat3, whereas Scg3 induces the phosphorylation of Src, MEK, and ERK1/2, but not Akt or Stat3. Despite the unknown receptor of Scg3, these results suggest that Scg3 and VEGF have different receptor signaling pathways. In this regard, their inhibitors could be used for alternative or combination therapy of diabetic retinopathy