Tyrosine-protein kinase that acts as a cell-surface receptor for VEGFA, VEGFC and VEGFD. Plays an essential role in the regulation of angiogenesis, vascular development, vascular permeability, and embryonic hematopoiesis. Promotes proliferation, survival, migration and differentiation of endothelial cells.

Promotes reorganization of the actin cytoskeleton. Isoforms lacking a transmembrane domain, such as isoform 2 and isoform 3, may function as decoy receptors for VEGFA, VEGFC and/or VEGFD. Isoform 2 plays an important role as negative regulator of VEGFA- and VEGFC-mediated lymphangiogenesis by limiting the amount of free VEGFA and/or VEGFC and preventing their binding to FLT4.

Modulates FLT1 and FLT4 signaling by forming heterodimers. Binding of vascular growth factors to isoform 1 leads to the activation of several signaling cascades. Activation of PLCG1 leads to the production of the cellular signaling molecules diacylglycerol and inositol 1,4,5-trisphosphate and the activation of protein kinase C.

Mediates activation of MAPK1/ERK2, MAPK3/ERK1 and the MAP kinase signaling pathway, as well as of the AKT1 signaling pathway. Mediates phosphorylation of PIK3R1, the regulatory subunit of phosphatidylinositol 3-kinase, reorganization of the actin cytoskeleton and activation of PTK2/FAK1. Required for VEGFA-mediated induction of NOS2 and NOS3, leading to the production of the signaling molecule nitric oxide (NO) by endothelial cells.

Phosphorylates PLCG1. Promotes phosphorylation of FYN, NCK1, NOS3, PIK3R1, PTK2/FAK1 and SRC

Homodimer in the presence of bound dimeric VEGFA, VEGFC or VEGFD ligands; monomeric in the absence of bound ligands. Can also form heterodimers with FLT1/VEGFR1 and KDR/VEGFR2. Interacts (tyrosine phosphorylated) with LFYN, NCK1, PLCG1.

Interacts (tyrosine-phosphorylated active form preferentially) with DAB2IP (via C2 domain and active form preferentially); the interaction occurs at the late phase of VEGFA response and inhibits KDR/VEGFR2 activity. Interacts with SHBSH2D2A/TSAD, GRB2, MYOF, CBL and PDCD6. Interacts (via C-terminus domain) with ERN1 (via kinase domain); the interaction is facilitated in a XBP1 isoform 1- and vascular endothelial growth factor (VEGF)-dependent manner in endothelial cells (PubMed:23529610).

Interacts (via juxtamembrane region) with chaperone PDCL3 (via thioredoxin fold region); the interaction leads to increased KDR/VEGFR2 abundance through inhibition of its ubiquitination and degradation (PubMed:23792958, PubMed:26059764). Interacts (tyrosine phosphorylated) with CCDC88A/GIV (via SH2-like region); binding requires autophosphorylation of the KDR/VEGFR2 C-terminal region (PubMed:25187647). Interacts with isoform 2 of BSG (PubMed:25825981).

Interacts with SLC31A1; this interaction is induced upon VEGFA stimulation leading to SLC31A1 and KDR subsequent co-internalization to early endosomes, thereby activating KDR downstream signaling in endothelial cells (PubMed:35027734)

(Microbial infection) Interacts with HIV-1 Tat

Detected in cornea (at protein level). Widely expressed

The second and third Ig-like C2-type (immunoglobulin-like) domains are sufficient for VEGFC binding

• Hemangioma, capillary infantile (HCI)

  A condition characterized by dull red, firm, dome-shaped hemangiomas, sharply demarcated from surrounding skin, usually presenting at birth or occurring within the first two or three months of life. They result from highly proliferative, localized growth of capillary endothelium and generally undergo regression and involution without scarring.

• Unknown disease