VEGFR-1

VEGFR-1, also known as Flt-1, is the highest-affinity receptor for VEGF-A and additionally binds VEGF-B and placental growth factor (PlGF). Despite its ligand affinity, its intrinsic kinase signaling is weak; instead VEGFR-1 largely modulates angiogenesis by sequestering VEGF-A away from VEGFR-2 and by recruiting monocytes and hematopoietic progenitors. A naturally secreted splice variant, sFlt-1, acts as a soluble decoy, and its excess is central to the pathogenesis of preeclampsia. VEGFR-1 also contributes to pathological neovascularization and tumor angiogenesis. Recombinant VEGFR-1 proteins are standard reagents for VEGF-family binding studies and anti-angiogenic antibody characterization.