Flt4

Developmental stage

Expressed in the skin and mesentery lymphatic vessels at 15.5 and 18.5 dpc (at protein level).

Domain

The first and second Ig-like C2-type (immunoglobulin-like) domains are sufficient for VEGFC binding. The fourth and fifth Ig-like C2-type (immunoglobulin-like) domains are sufficient for homodimerization. The fifth and seventh Ig-like C2-type (immunoglobulin-like) domains are required for autophosphorylation and further activation.

Function

Tyrosine-protein kinase that acts as a cell-surface receptor for VEGFC and VEGFD, and plays an essential role in adult lymphangiogenesis and in the development of the vascular network and the cardiovascular system during embryonic development. Promotes proliferation, survival and migration of endothelial cells, and regulates angiogenic sprouting. Signaling by activated FLT4 leads to enhanced production of VEGFC, and to a lesser degree VEGFA, thereby creating a positive feedback loop that enhances FLT4 signaling. Modulates KDR signaling by forming heterodimers. Mediates activation of the MAPK1/ERK2, MAPK3/ERK1 signaling pathway, of MAPK8 and the JUN signaling pathway, and of the AKT1 signaling pathway. Phosphorylates SHC1. Mediates phosphorylation of PIK3R1, the regulatory subunit of phosphatidylinositol 3-kinase. Promotes phosphorylation of MAPK8 at 'Thr-183' and 'Tyr-185', and of AKT1 at 'Ser-473'.

Post-translational modifications

Autophosphorylated 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 in response to H(2)O(2) is mediated by a process that requires SRC and PRKCD activity. Phosphorylation at Tyr-1068 is required for autophosphorylation at additional tyrosine residues. Phosphorylation at Tyr-1063 and Tyr-1337 is important for interaction with CRK and subsequent activation of MAPK8. Phosphorylation at Tyr-1230, Tyr-1231 and Tyr-1337 is important for interaction with GRB2 and subsequent activation of the AKT1 and MAPK1/ERK2 and/or MAPK3/ERK1 signaling pathways. In response to endothelial cell adhesion onto collagen, can also be phosphorylated in the absence of FLT4 kinase activity by SRC (By similarity).

Sequence Similarities

Belongs to the protein kinase superfamily. Tyr protein kinase family. CSF-1/PDGF receptor subfamily.

Tissue Specificity

Expressed in adult lung and liver, and in fetal liver, brain, intestine and placenta.

Cellular localization

• Cell membrane
• Single-pass type I membrane protein
• Cytoplasm
• Nucleus
• Ligand-mediated autophosphorylation leads to rapid internalization.

Alternative names

Flt-4, Vegfr3, Flt4, Vascular endothelial growth factor receptor 3, VEGFR-3, Fms-like tyrosine kinase 4, Tyrosine-protein kinase receptor FLT4, FLT-4

Database links

swissprot:P35917 entrezGene:14257

Other research areas

• Immuno-oncology