p-Flk-1 (Tyr 951) Antibody: sc-16628

Flk-1 Background Information
Three cell membrane receptor tyrosine kinases, Flt (also designated VEGF-R1) (1–3), Flk-1 (also designated VEGF-R2) (4–6) and Flt-4 (7), putatively involved in the growth of endothelial cells, are characterized by the presence of seven immunoglobulin-like sequences in their extracellular domain. These receptors exhibit high degrees of sequence homology to each other as well as lesser degrees of homology to the class III receptors, including CSF-1/Fms, PDGR, SLFR/Kit and Flt-3/Flk-2. Two members of this receptor class, Flt-1 and Flk-1, have been shown to represent high affinity receptors for vascular endothelial growth factors (VEGFs) (3,5). In response to VEGF binding, Flk-1 undergoes autophosphorylation in the kinase insert domain on Tyr 951 and Tyr 996 and in the tyrosine kinase catalytic domain on Tyr 1054 and Tyr 1059 (7,8). Upon activation, Flk-1 recruits several adapter proteins, including Shc, Grb2, Nck and protein tyrosine phosphatases SHP-1 and SHP-2 (9). The mediation of VEGF signaling by Flk-1 promotes proliferation, chemotaxis, prouting and angiogenesis (10).