VEGFR-2/KDR-Fc Chimera, Soluble (VEGFR-2/KDR) Human Active Protein

Vascular endothelial growth factor (VEGF) is a major growth factor for endothelial cells. This gene encodes one of the two receptors of the VEGF. This receptor, known as kinase insert domain receptor, is a type III receptor tyrosine kinase. It functions as the main mediator of VEGF-induced endothelial proliferation, survival, migration, tubular morphogenesis and sprouting. The signalling and trafficking of this receptor are regulated by multiple factors, including Rab GTPase, P2Y purine nucleotide receptor, integrin alphaVbeta3, T-cell protein tyrosine phosphatase, etc.. Mutations of this gene are implicated in infantile capillary hemangiomas. [provided by RefSeq, May 2009]

Function: 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. Ref.2 Ref.9 Ref.10 Ref.11 Ref.12 Ref.13 Ref.14 Ref.16 Ref.18 Ref.19 Ref.21 Ref.23 Ref.24 Ref.25 Ref.27 Ref.31 Ref.32 Ref.33 Ref.35 Ref.45 Ref.47 Ref.50 Ref.51

Catalytic activity: ATP + a [protein]-L-tyrosine = ADP + a [protein]-L-tyrosine phosphate. Ref.15 Ref.16

Enzyme regulation: Present in an inactive conformation in the absence of bound ligand. Binding of VEGFA, VEGFC or VEGFD leads to dimerization and activation by autophosphorylation on tyrosine residues. Inhibited by the small molecule PTK inhibitor SU5614 ((3Z)-5-Chloro-3-[(3,5-dimethyl-1H-pyrrol-2-yl)methylene]-1,3-dihydro-2H-indol-2-one). May be regulated by hydrogen sulfide (H2S) levels via a H2S-sensitive intracellular disulfide bond. Ref.15 Ref.16 Ref.23 Ref.46

Subunit structure: 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 FLT4/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 with HIV-1 Tat. Ref.1 Ref.2 Ref.9 Ref.11 Ref.16 Ref.17 Ref.19 Ref.20 Ref.21 Ref.23 Ref.24 Ref.25 Ref.28 Ref.33 Ref.35 Ref.45 Ref.51 Ref.52

Subcellular location: Isoform 1: Cell membrane; Single-pass type I membrane protein. Cytoplasm. Nucleus. Cytoplasmic vesicle. Early endosome. Note: Detected on caveolae-enriched lipid rafts at the cell surface. Is recycled from the plasma membrane to endosomes and back again. Phosphorylation triggered by VEGFA binding promotes internalization and subsequent degradation. VEGFA binding triggers internalization and translocation to the nucleus. Ref.1 Ref.9 Ref.11 Ref.16 Ref.19 Ref.22 Ref.26 Ref.31 Ref.33 Ref.34Cell junction

By similarity. Note: Localized with RAP1A at cell-cell junctions

By similarity. Ref.1 Ref.9 Ref.11 Ref.16 Ref.19 Ref.22 Ref.26 Ref.31 Ref.33 Ref.34Isoform 2: Secreted

Probable Ref.1 Ref.9 Ref.11 Ref.16 Ref.19 Ref.22 Ref.26 Ref.31 Ref.33 Ref.34. Isoform 3: Secreted Ref.1 Ref.9 Ref.11 Ref.16 Ref.19 Ref.22 Ref.26 Ref.31 Ref.33 Ref.34.

Tissue specificity: Detected in cornea (at protein level). Widely expressed. Ref.2

Domain: The second and third Ig-like C2-type (immunoglobulin-like) domains are sufficient for VEGFC binding. Ref.52

Post-translational modification: N-glycosylated. Ref.11 Ref.52 Ref.53Ubiquitinated. Tyrosine phosphorylation of the receptor promotes its poly-ubiquitination, leading to its degradation via the proteasome or lysosomal proteases. Ref.19 Ref.26 Ref.31Autophosphorylated on tyrosine residues upon ligand binding. Autophosphorylation occurs in trans, i.e. one subunit of the dimeric receptor phosphorylates tyrosine residues on the other subunit. Phosphorylation at Tyr-951 is important for interaction with SH2D2A/TSAD and VEGFA-mediated reorganization of the actin cytoskeleton. Phosphorylation at Tyr-1175 is important for interaction with PLCG1 and SHB. Phosphorylation at Tyr-1214 is important for interaction with NCK1 and FYN. Dephosphorylated by PTPRB. Dephosphorylated by PTPRJ at Tyr-951, Tyr-996, Tyr-1054, Tyr-1059, Tyr-1175 and Tyr-1214. Ref.10 Ref.11 Ref.15 Ref.16 Ref.18 Ref.22 Ref.23 Ref.24 Ref.27 Ref.29 Ref.30 Ref.47 Ref.51The inhibitory disulfide bond between Cys-1024 and Cys-1045 may serve as a specific molecular switch for H2S-induced modification that regulates VEGFR2 function.

Involvement in disease: Hemangioma, capillary infantile (HCI) [MIM:602089]: 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.Note: Disease susceptibility is associated with variations affecting the gene represented in this entry. Ref.54 Ref.57Plays a major role in tumor angiogenesis. In case of HIV-1 infection, the interaction with extracellular viral Tat protein seems to enhance angiogenesis in Kaposi's sarcoma lesions.

Sequence similarities: Belongs to the protein kinase superfamily. Tyr protein kinase family. CSF-1/PDGF receptor subfamily.Contains 7 Ig-like C2-type (immunoglobulin-like) domains.Contains 1 protein kinase domain.