Vascular endothelial growth factor receptor 1; Vascular endothelial growth factor receptor 2 (VEGFR-1; VEGFR-2)

Vascular endothelial growth factor receptor 1 (VEGFR-1, Flt-1) and vascular endothelial growth factor receptor 2 (VEGFR-2, KDR/Flk-1) are closely related receptor tyrosine kinases that serve as the principal receptors for various VEGF family ligands, including VEGF-A, VEGF-B, VEGF-C, and placental growth factor (PlGF)[1][2][3][7]. Both receptors are composed of seven extracellular immunoglobulin-like domains, a single transmembrane segment, and an intracellular tyrosine kinase domain with a kinase insert[2][6][7]. VEGFR-2 mediates most of the angiogenic and permeability effects of VEGF and drives endothelial cell proliferation, migration, and survival, making it the primary signaling receptor for blood vessel formation in both embryonic development and disease states such as cancer and retinopathy[1][3][5][6]. VEGFR-1, with lower kinase activity, primarily modulates VEGFR-2 signaling by acting as a decoy receptor, binding VEGF-A with higher affinity but limiting the degree of VEGFR-2 activation; it is also implicated in monocyte migration and pathological angiogenesis[3][5][7]. Both receptors are validated therapeutic targets, and multiple anti-angiogenic drugs targeting their pathways are widely used in oncology and ophthalmology[5][6].

Other names

Fms-related tyrosine kinase 1 (Flt-1)Kinase insert domain receptor (KDR)fetal liver kinase 1 (Flk-1, in mouse)

Inhibition of ligand binding (e.g., anti-VEGF antibodies); Kinase inhibition (tyrosine kinase inhibitors); Trap/decoy receptor formation (VEGF Trap/aflibercept); Downregulation of VEGFR signaling pathways