Receptor for VEGF or VEGFC. Has a tyrosine-protein kinase activity. Combinations of multiple VEGF receptors are required for development of different blood vessel types in the embryo. Involved in angiogenesis, specifically in VEGF-induced sprouting of new blood vessels. Particularly involved in artery formation. Does not appear to be required for hematopoiesis. ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Interacts with isoform VEGF165 of vegfaa and isoform VEGF171 of vegfab. First expressed in embryos between 5- and 7-somites. At 7 somites, expressed in discrete bilateral stripes both anteriorly and posteriorly, and in a transverse ectodermal stripe in the hindbrain. From 7-somites, expression seems to extend caudally from the head, and in both directions in the trunk region, until by 20-somites, expression is detected as a continuous band from the anterior head region to the tailbud. Concurrently, cells expressing kdrl in the mid- and posterior trunk regions converge medially. By 24 hours post-fertilization (hpf), expressed in all the endothelial cells lining the vasculature. Phosphorylated and activated by vegfaa and vegfab. Belongs to the protein kinase superfamily. Tyr protein kinase family. CSF-1/PDGF receptor subfamily. Was originally thought to be an ortholog of KDR, but PubMed:18516225 has shown that it represents a fourth vertebrate vascular endothelial growth factor receptor (VEGFR) that is not present in eutherian mammals (marsupials and placental mammals).